Best for Gut Health

Probiotics demonstrate consistent, clinically meaningful improvements in gut health across multiple human RCTs and meta-analyses, with proven efficacy for specific conditions like food allergy prevention, IBS symptom reduction, and microbiota modulation. Effects are generally strain-specific and dose-dependent, with strongest evidence for multi-strain formulations over 8+ weeks.

Psyllium husk demonstrates strong evidence of efficacy for gut health, particularly for constipation and IBS symptoms in humans. Multiple well-designed RCTs show clinically meaningful improvements in bowel function and microbiota composition, with consistent results across diverse populations.

Boswellia serrata demonstrates strong evidence for improving gut health, particularly in IBS, acute diarrhea, and inflammatory bowel conditions. Multiple human RCTs and observational studies show consistent benefits with anti-inflammatory and antimicrobial mechanisms.

Linaclotide is a guanylate cyclase-C agonist with strong evidence of efficacy for constipation-predominant gut disorders. Multiple high-quality RCTs and meta-analyses demonstrate consistent improvements in bowel movements, abdominal pain, and bloating in both adults and children with IBS-C and functional constipation.

Ashwagandha shows probable efficacy for gut health based on 2-3 human RCTs demonstrating improvements in constipation and bowel function, though evidence is limited by small sample sizes, short durations, and use of proprietary blends that conflate results with other botanicals.

Ipamorelin shows probable efficacy for postoperative ileus in humans based on one RCT demonstrating a modest 7.3-hour reduction in time to first tolerated meal, but evidence is limited to a single human trial with modest effect size and lacks independent replication.

GLP-1 agonists and analogues demonstrate consistent effects on gut microbiota composition and promote beneficial bacterial genera and metabolite production in both animal and human studies, but direct evidence of clinically meaningful improvements in gut health endpoints remains limited and mixed.

Omega-3 fatty acids show probable benefit for gut health through microbiota modulation and anti-inflammatory effects in humans, supported by multiple RCTs demonstrating reductions in gastrointestinal infections and alterations in microbial composition. However, evidence remains inconsistent across conditions, with limited long-term data and some concerning findings in inflammatory bowel disease.

Vitamin D3 shows probable benefit for gut health through microbiota modulation and barrier function improvement in humans, with consistent effects on microbial composition and zonulin reduction in IBS patients, though evidence remains limited by small sample sizes and inconsistent outcomes across different gut conditions.

Zinc supplementation shows probable efficacy for specific gut health conditions in humans, particularly infectious diarrhea and intestinal permeability in Crohn's disease, with some evidence in pediatric GI diseases. However, results are inconsistent across conditions and study quality is mixed.

Berberine demonstrates probable efficacy for gut health through microbiota modulation and barrier integrity improvements, supported by multiple human RCTs and consistent animal studies. However, evidence is limited by small sample sizes, short trial durations, and modest effect sizes in most human studies.

Curcumin supplementation shows probable benefits for gut health through microbiota modulation and reduced gastrointestinal symptoms in humans, supported by multiple RCTs and mechanistic studies, but evidence is limited by small sample sizes and inconsistent outcome measures across trials.

Resveratrol shows promise for modulating gut microbiota composition and reducing markers of intestinal inflammation in multiple human and animal studies, but human efficacy evidence remains limited to small RCTs with inconsistent effect sizes and short intervention periods. Beneficial effects on microbiota diversity and microbial metabolite production are more consistently demonstrated in animal models than in humans.

Collagen peptides show probable benefit for gut health through multiple mechanisms including barrier function support and microbiota modulation, but evidence relies heavily on mechanistic studies and a small number of human trials with modest sample sizes and inconsistent outcomes.

Melatonin shows probable benefits for gut health through microbiota modulation and intestinal barrier enhancement, supported by consistent animal studies and emerging human evidence. However, human efficacy is not yet conclusively proven due to limited RCT data and small sample sizes.

Vitamin K2 shows probable efficacy for gut health through improvements in glycemic control and inflammatory markers, demonstrated in 2-3 human RCTs with mechanistic evidence of microbiota modulation. However, evidence is limited by small sample sizes, short durations, and lack of independent replication specifically focused on gut health as a primary outcome.

Elderberry shows probable efficacy for gut health through microbiota modulation and prebiotic effects in 2-3 human studies, but evidence remains limited by small sample sizes, short intervention periods, and lack of independent replication across trials.

Aged garlic extract shows probable benefits for gut health through microbiota modulation and intestinal barrier support, with evidence from multiple human RCTs demonstrating improved microbial diversity and reduced inflammation. However, efficacy remains modest and inconsistently reported across studies, with most human data limited to small samples and short durations.

Green Tea Extract (EGCG) shows probable benefits for gut health through microbiota modulation and intestinal barrier function in humans, supported by mechanistic studies and preliminary clinical evidence, but efficacy is not yet conclusively proven due to limited high-quality RCT data and modest sample sizes.

Spirulina shows probable benefits for gut health through improved intestinal permeability, antioxidant status, and microbiota composition in humans with IBS, supported by at least 2 well-designed RCTs. However, evidence remains limited to small sample sizes and short intervention periods, with human efficacy not yet conclusively established across broader populations.

Vitamin C supplementation shows plausible benefits for gut microbiota composition and diversity in humans, with consistent evidence that it increases beneficial bacterial abundance and short-chain fatty acid production. However, clinical efficacy for broader gut health outcomes remains incompletely proven, and most human studies are small pilots with limited follow-up.

Vitamin B12 supplementation shows probable efficacy for treating gut health issues related to B12 deficiency, particularly chronic diarrhea and malabsorption-related gastrointestinal symptoms in humans. However, evidence is limited to small observational studies and case reports; only 4 human RCTs exist in this dataset, most focusing on non-gut outcomes.

Vitamin E shows probable benefit for gut health through improved intestinal barrier function and reduced inflammation in inflammatory bowel disease, supported by multiple human observational studies and mechanistic animal research. However, evidence remains incomplete due to limited human RCTs and inconsistent findings across disease types.

Selenium shows probable efficacy for gut health, particularly for inflammatory bowel disease (ulcerative colitis) and gut microbiota modulation, supported by 3 human RCTs and multiple well-designed animal studies. However, evidence is limited by small human sample sizes, short intervention periods, and lack of independent replication.

Spermidine shows probable efficacy for gut health in humans, with evidence of improved barrier function, endothelial function, and microbiota modulation in 2 RCTs and several observational studies. However, the human evidence base is small (n<100 total across RCTs), and most mechanistic data comes from animal models.

Urolithin A shows emerging promise for gut health through mechanisms of microbiota modulation and intestinal barrier enhancement, but human evidence remains limited to small trials with mixed results on clinically meaningful endpoints.

Sulforaphane shows probable efficacy for gut health through multiple mechanisms including barrier integrity, microbiota modulation, and anti-inflammatory effects, but human evidence remains limited to 2 RCTs with modest sample sizes and mixed primary outcomes.

Pomegranate extract demonstrates probable efficacy for gut health through multiple human RCTs showing consistent improvements in beneficial bacteria abundance, short-chain fatty acid production, and markers of gut barrier integrity. However, evidence remains limited by small sample sizes, short intervention periods, and lack of large-scale independent replication.

Grape seed extract (GSE) shows probable efficacy for improving gut health through barrier function enhancement and microbiota modification in both animal and limited human studies, but robust, large-scale human RCTs are lacking to confirm clinical significance.

Olive leaf extract shows probable efficacy for gut health through mechanisms involving barrier integrity, microbiota modulation, and anti-inflammatory effects, supported by consistent findings across multiple human observational studies and animal models. However, evidence remains limited to 2 human RCTs (both small, focused on bioavailability rather than clinical outcomes) and lacks large-scale, independently replicated human efficacy trials.

Schisandra chinensis modulates gut microbiota composition and shows promise for improving metabolic markers and intestinal health in humans, but evidence remains limited to small RCTs and observational studies with modest effect sizes. Efficacy is probable but not conclusively proven.

Rapamycin/sirolimus shows probable efficacy for specific gut health conditions (ulcerative colitis, gastrointestinal bleeding, intestinal barrier dysfunction) based on multiple human observational studies and mechanistic evidence, but the evidence base consists primarily of small observational studies and case series rather than large-scale RCTs, limiting definitive conclusions about general gut health applications.

Butyrate, a short-chain fatty acid produced by gut bacteria, shows probable efficacy for gut health based on multiple human studies demonstrating increased butyrate-producing bacteria and improved microbial function with dietary interventions. However, most evidence is observational or mechanistic; only a few RCTs directly tested butyrate supplementation or fiber interventions that increase butyrate production.

Peppermint oil shows probable efficacy for IBS symptom relief in multiple human RCTs and meta-analyses, but recent high-quality trials report null results and substantial placebo response, making clinical benefit inconclusive.

CDP-choline shows probable efficacy for gut health and IBD based on 2-3 human observational studies and mechanistic animal research, but evidence is limited by lack of large-scale human RCTs specifically designed for gut health outcomes.

L-Glutamine shows probable efficacy for specific gut health conditions, particularly postinfectious IBS-D with strong RCT evidence, but broader claims about intestinal permeability lack consistent support. Human trial evidence is limited to small samples and specific disease contexts.

5-HTP shows probable benefit for gut health through multiple mechanistic pathways, particularly in constipation relief and microbiota modulation, supported by 2-3 human RCTs and consistent animal evidence. However, efficacy remains unproven in large, well-controlled human trials, and most studies are small with mixed effect sizes.

Larazotide acetate shows probable efficacy for celiac disease symptom relief in humans, particularly during gluten challenge, with consistent positive results across multiple RCTs. However, evidence remains limited by modest sample sizes and inconsistent effects on some endpoints like intestinal permeability biomarkers.

Octreotide shows probable efficacy for specific gut health issues like gastrointestinal bleeding, pancreatitis, and intestinal barrier function, supported by multiple human studies and mechanistic research. However, evidence remains inconsistent across conditions, limited by small sample sizes, and lacking large-scale RCTs.

Vitamin B2 (riboflavin) shows moderate evidence for supporting gut health, primarily through promoting butyrate production and reducing inflammatory markers in clinical populations. However, effects on overall microbiota composition are minimal, and human evidence is limited to small, short-term trials.

Vitamin B3 shows probable efficacy for gut health through multiple human studies demonstrating improved microbiota composition and barrier function, but evidence is limited by small sample sizes, observational designs, and lack of large-scale RCTs specifically targeting gut health outcomes.

BPC-157 shows promising effects for gastrointestinal protection and healing in extensive animal studies, but human evidence remains extremely limited with no controlled trials specifically for gut health.

Creatine monohydrate has been studied in the context of gut health, with one case report suggesting potential benefits for Crohn's disease and animal studies showing improvements in ileal microbiota composition. However, evidence for gut health efficacy in humans is minimal and limited to a single case observation.

TB-500 shows promise for gut health in animal models and observational human studies, but lacks robust human clinical trials. Evidence suggests both protective and harmful effects on intestinal barrier function.

Selank shows plausible benefits for gut health in animal models, with evidence that it reduces stress-induced intestinal pathology and restores microbiota balance in rats. However, no human clinical trials exist for this goal, limiting proof of efficacy in humans.

Epithalon shows consistent effects on gastrointestinal enzyme activity in aged rats, but no human studies exist. Efficacy for gut health in humans remains unproven.

KPV demonstrates consistent anti-inflammatory effects in animal models of colitis and gut inflammation, with multiple studies showing meaningful improvements in disease markers. However, no human clinical trials exist, making efficacy in humans unproven.

Thymosin alpha-1 shows plausible mechanisms for supporting gut health through immune modulation and barrier integrity restoration, but evidence remains largely preclinical or observational. No robust human RCTs specifically targeting gut health outcomes have demonstrated clear clinical efficacy.

MOTS-c shows promising anti-inflammatory and gut-protective effects in animal models of colitis, but efficacy in humans is unproven. Only one human observational study exists (measuring serum levels in disease context), with no human intervention trials demonstrating clinical benefit for gut health.

SS-31 is a mitochondria-targeted peptide discussed as a potential therapeutic agent for gut health through reduction of mitochondrial oxidative stress, but evidence remains limited to mechanistic reviews and a single proof-of-concept study in an engineered delivery system. No human efficacy trials for gut health have been published.

LL-37 shows plausible mechanisms for supporting gut health through antimicrobial and barrier-protective effects, but evidence in humans remains limited to small observational studies and one infant RCT. No large-scale human trials demonstrate clinical efficacy for general gut health.

Kisspeptin's role in gut health is not directly demonstrated in any of these abstracts. Instead, the evidence shows kisspeptin acts as a biomarker for reproductive and metabolic health, with emerging data suggesting gut microbiota influences kisspeptin signaling in the hypothalamic-pituitary-gonadal axis, but no direct evidence that kisspeptin supplementation improves gut health outcomes.

GHRP-6 shows consistent prokinetic effects in animal models of gastrointestinal dysfunction, but evidence is almost entirely limited to rodent and pig studies. No rigorous human RCTs demonstrate efficacy for gut health in the abstracts provided.

Melanotan 2 consistently reduces food intake in animal models through melanocortin receptor signaling, but no human studies exist to demonstrate efficacy for gut health or any clinical outcomes.

GDF-11 shows promise for gut health through anti-inflammatory mechanisms demonstrated in cell culture and one murine model, but no human efficacy trials exist. Current evidence is limited to mechanistic studies and a single animal model of chemotherapy-induced mucositis.

VIP shows promise for gut health through animal studies demonstrating anti-inflammatory effects and modulation of intestinal motility and barrier function, but no rigorous human RCTs exist to prove efficacy in any gut health condition.

Vilon (Lys-Glu) shows consistent positive effects on digestive enzyme activity in aged rats, but efficacy in humans remains completely unproven. All evidence comes from animal models with no human trials conducted.

Magnesium supplementation shows promise for gut health through microbiota modulation in animal models and limited human evidence, but human efficacy for gut health specifically is not yet proven. Most human studies examine magnesium for unrelated conditions (muscle cramps, cardiac arrhythmias, chemotherapy side effects) rather than primary gut health outcomes.

NAC shows plausible mechanisms for supporting gut health through antioxidant and microbiota-modulating effects, but human evidence is limited to small studies with mixed results. Most robust data comes from animal models and mechanistic studies rather than definitive human trials.

Quercetin shows consistent benefits for gut microbiota composition and intestinal barrier function in animal models, but human evidence is extremely limited with only 2 RCTs identified, neither of which were in human subjects (one was in laying hens, one in calves). Efficacy in humans remains unproven.

NMN shows plausible mechanisms for supporting gut health through microbiota modulation and SCFA production in human-relevant studies, but current evidence is limited to 3 human RCTs with small-to-moderate sample sizes and mechanistic exploration rather than clinically validated gut health outcomes.

CoQ10 shows plausible mechanisms for gut health support through antioxidant and anti-inflammatory pathways in animal and observational human studies, but no randomized controlled trials directly demonstrate efficacy for gut health outcomes in humans.

Tongkat Ali shows anti-parasitic and anti-protozoal activity in laboratory studies against gastrointestinal pathogens, but no human clinical trials demonstrate efficacy for gut health. Evidence is limited to in-vitro and animal models.

Boron shows promise for gut health in animal models, with optimal doses (40-80 mg/L) improving intestinal structure, immune function, and tight junction integrity in rats. However, efficacy in humans remains unproven—only one human study exists, which examined gene expression changes rather than clinical gut health outcomes.

Milk thistle shows plausible mechanisms for supporting gut health through microbiota modulation and anti-inflammatory effects, demonstrated primarily in animal models and mechanistic studies. However, human evidence for gut health specifically is limited to one small RCT with a multi-ingredient formulation and observational reports, making efficacy in humans unproven.

Rhodiola rosea and its active constituent salidroside show consistent microbiota-modulating and gut barrier-protective effects in animal models, but evidence remains limited to preclinical studies with only one small human RCT identified. Efficacy in human gut health is plausible but unproven.

Maca root shows emerging evidence for gut health through animal and in-vitro studies demonstrating prebiotic effects and microbiota modulation, but lacks human clinical trials specifically testing gut health outcomes. Current evidence is insufficient to prove efficacy in humans.

Black seed oil shows plausible benefit for gut health through antimicrobial and anti-inflammatory mechanisms, but evidence is limited to 1 small human study (n=14) and multiple animal/mechanistic studies. Efficacy in humans remains unproven.

Fenugreek shows plausible mechanisms for gut health through microbiota modulation and anti-inflammatory effects, but evidence in humans is limited to observational studies and traditional use reports. No rigorous human RCTs specifically testing gut health outcomes were identified.

Glucosamine + Chondroitin modulates gut microbiota composition in humans and animals, but there is no evidence it improves gut health outcomes or clinical symptoms related to gastrointestinal function.

B vitamins show plausible mechanisms for supporting gut health through microbiota modulation and short-chain fatty acid production, but direct efficacy evidence in humans is limited. Most evidence is mechanistic or observational rather than from rigorous clinical trials.

Iron supplementation effectively increases hemoglobin and ferritin levels in deficient populations, but evidence for gut health specifically is limited to mechanistic animal studies and observational data showing iron can harm the microbiome and worsen inflammation.

Iodine shows plausible benefits for gut health in animal models through improved intestinal morphology and microbial composition, but evidence is primarily limited to animal studies with no human RCTs demonstrating efficacy for gut health as a primary outcome.

Copper supplementation shows mechanistic effects on gut microbiota composition and resistance gene expression in animal models, but lacks rigorous human RCT evidence demonstrating direct benefits for gut health. Most human data concerns copper deficiency treatment rather than supplementation for healthy individuals.

Chromium picolinate shows plausible gut health effects in animal models and some mechanistic promise in human studies, but direct evidence of efficacy for gut health in humans is absent. Most human studies focus on metabolic outcomes (diabetes, NAFLD) rather than gut-specific measures.

Biotin shows plausible mechanisms for supporting gut health through microbiota composition and anti-inflammatory pathways, but human evidence is limited to one small RCT and observational case reports. Animal studies demonstrate consistent effects on colitis and dysbiosis, but efficacy in human gut health remains unproven.

Fisetin shows consistent beneficial effects on gut microbiota composition and intestinal barrier function in animal models of colitis and infection, with emerging evidence for microbiota-mediated anti-inflammatory effects. However, no human RCTs exist demonstrating efficacy for general gut health, limiting proof of clinical benefit.

Astaxanthin shows consistent effects on gut health markers in animal models (poultry, fish, ducks) including improved intestinal barrier function, reduced inflammation, and favorable microbiota shifts. However, no human studies directly assess gut health outcomes; the single human RCT measured athletic performance, not gastrointestinal endpoints.

Glutathione supplementation shows plausible mechanisms for gut health benefits (microbiome composition, oxidative stress reduction, intestinal barrier function) supported by one human RCT and multiple animal models, but human efficacy evidence remains limited and largely indirect.

Pycnogenol has not been adequately studied for gut health specifically. While preliminary evidence suggests it may benefit irritable bowel syndrome symptoms and influence gut microbiota composition in ADHD patients, there are no dedicated human RCTs demonstrating efficacy for general gut health or digestive function.

TUDCA shows consistent mechanistic promise for gut health through microbiota modulation and bile acid metabolism, but human efficacy evidence remains limited to small observational studies and one 16-week RCT with null primary outcomes. Safety is established, but clinical benefit in gut health specifically is not yet proven.

Nattokinase shows plausible benefits for gut health through microbiota modulation and anti-inflammatory effects in multiple animal models, but evidence is limited to a single human case series and predominantly animal/in-vitro studies. Efficacy in humans remains unproven.

Bovine colostrum shows plausible mechanisms for supporting gut health through immunoglobulins, lactoferrin, and oligosaccharides, but human efficacy remains unproven. A 2025 systematic review found inconclusive clinical benefits in pediatric gut health, and the single human RCT in children with autism showed tolerability but only suggestive improvements in GI symptoms without definitive evidence of efficacy.

Beta-glucans show plausible mechanisms for supporting gut health through microbiota modulation and immune regulation, but human efficacy evidence remains limited. No RCTs directly measuring clinical gut health outcomes are present in this literature set.

Cordyceps shows consistent beneficial effects on gut health markers in animal models, with mechanisms involving microbiota modulation, barrier function improvement, and anti-inflammatory effects. However, only 3 human observational studies exist with no human RCTs, leaving efficacy in humans unproven.

Reishi (Ganoderma lucidum) shows plausible mechanisms for supporting gut health through microbiota modulation and SCFA production in animal and mechanistic studies, but human efficacy evidence is minimal and limited to observational designs without rigorous controls.

Chaga (Inonotus obliquus) shows consistent gut microbiota modulation and intestinal barrier improvements in animal models, but no human clinical trials exist. Efficacy is plausible but unproven in humans.

Epicatechin shows plausible mechanisms for supporting gut health through microbiota modulation and barrier function in mechanistic studies, but human efficacy evidence is absent. No randomized controlled trials in humans exist; evidence relies on bioavailability studies, in vitro models, animal research, and mechanistic reviews.

Apigenin shows promise for gut health in animal models, reducing intestinal damage, inflammation, and restoring barrier integrity. However, no human trials have been conducted; all evidence comes from animal studies (Drosophila, broilers, mice), making efficacy in humans unproven.

Pterostilbene shows consistent mechanistic effects on gut microbiota composition and intestinal barrier function in animal models, but human efficacy for gut health remains unproven—only 2 human RCTs exist, and neither directly measured clinical gut health outcomes.

Bromelain shows plausible mechanisms for supporting gut health through anti-inflammatory and barrier-protective effects demonstrated in animal models and in vitro studies, but human efficacy for gut health specifically remains unproven. No human RCTs directly testing bromelain for gut health outcomes were identified.

Lactoferrin has been extensively studied in preterm and formula-fed infants for gut health, but the evidence does not demonstrate proven efficacy. Most large RCTs show null or inconclusive results for primary endpoints like sepsis prevention and microbiota changes, despite plausible mechanisms and some positive findings in specific populations.

Stinging nettle (Urtica dioica) shows plausible mechanisms for gut health support through antioxidant and anti-inflammatory effects, but evidence of direct efficacy for gut health in humans is limited to one small RCT and observational reports. Most evidence is mechanistic, botanical survey data, or animal studies.

Cistanche shows consistent gut microbiota-modulating effects and intestinal barrier protection in multiple animal studies, but zero human RCTs exist. Efficacy is plausible based on mechanistic animal data but unproven in humans.

Tribulus terrestris shows plausible mechanisms for supporting gut health through microbiota modulation and barrier function in animal models, but human efficacy evidence is absent. Current data is limited to animal studies and ethnobotanical documentation without clinical proof of gut health benefits in humans.

Echinacea shows plausible mechanisms for supporting gut health through microbiota modulation and intestinal barrier integrity, but evidence remains primarily in animal and in-vitro models with minimal human data. No rigorous human RCTs demonstrate clinically meaningful efficacy for gut health specifically.

Lemon balm shows plausible mechanisms for gut health support through anti-inflammatory and spasmolytic properties demonstrated in animal and in-vitro studies, but human efficacy for gut health specifically remains largely unproven. The limited human evidence focuses on anxiety and IBS symptoms rather than direct gut health outcomes.

CLA shows mechanistic promise for gut health through anti-inflammatory effects and microbiota modulation in animal models and preliminary human studies, but evidence of clinical efficacy in humans remains limited. Only one small pilot human RCT (n=15) exists, insufficient to establish proven efficacy.

SAMe's role in gut health is suggested by mechanistic studies showing it acts as a bacterial metabolite that influences intestinal function and microbial metabolism, but there is no direct human evidence demonstrating that SAMe supplementation improves gut health outcomes.

Whey protein's effects on gut health are mixed and primarily demonstrated in animal models. Human studies show modest changes in microbiota composition and some improvements in intestinal permeability, but evidence of clinically meaningful gut health benefits remains limited and inconsistent.

Astragalus shows plausible mechanisms for gut health through microbiota modulation and intestinal barrier support, but evidence is primarily from animal studies and mechanistic research. Only 3 human RCTs exist in this dataset, and none specifically measure gut health endpoints with validated metrics.

Hyaluronic acid shows plausible mechanisms for gut health support based on animal studies demonstrating intestinal uptake and mucoadhesion, but there is no human evidence directly proving efficacy for gut health outcomes. The single human RCT studied joint health, not gut health.

Forskolin shows promise for gut health through animal studies demonstrating enhanced barrier function, host defense gene expression, and disease resistance in poultry models. However, no human clinical trials exist, and efficacy in humans remains unproven.

Betaine HCl demonstrates plausible mechanisms for supporting gut health through microbiota modulation and intestinal barrier function in animal models, but human evidence for gut health specifically is limited to observational data and mechanistic studies without robust RCT confirmation of efficacy.

Lion's Mane polysaccharides show promising mechanisms for gut health through microbiota modulation and intestinal barrier support, but efficacy in humans has not been demonstrated. All evidence is from animal models, in-vitro studies, or mechanistic reviews; no human RCTs or observational studies with clinical outcomes exist.

Alpha-GPC has not been proven to improve gut health in humans. Animal studies show mixed results: some suggest protective effects against intestinal inflammation, while others indicate potential harm to gut microbiota composition and cardiovascular risk through microbiota-dependent mechanisms.

Bacopa monnieri has not been directly studied for gut health outcomes in humans. Evidence is limited to mechanistic reviews suggesting potential gut-brain axis benefits and one animal study showing metabolic changes in fecal markers, but no human clinical trials demonstrate efficacy for gut health as a primary outcome.

Ginkgo biloba shows plausible mechanisms for supporting gut health through microbiota modulation and anti-inflammatory effects, but evidence comes almost entirely from animal studies and mechanistic reviews. No human RCTs directly testing gut health outcomes were identified in this literature set.

Panax ginseng shows plausible mechanisms for supporting gut health through microbiota modulation and intestinal barrier function in animal and mechanistic studies, but human clinical evidence remains absent. No human RCTs demonstrate efficacy for gut health as a primary outcome.

PQQ shows consistent beneficial effects on gut health markers in animal studies (pigs, mice, Drosophila), including improved intestinal morphology, antioxidant enzyme activity, and microbiota composition. However, only 1 small human observational study exists, making human efficacy unproven.

Vinpocetine shows promise for gut health primarily through animal studies demonstrating protective effects against gastric damage and modulation of gut microbiota, but human efficacy remains unproven. Two human RCTs exist but focus on pharmacokinetics and brain distribution rather than gut health outcomes.

Centrophenoxine shows gastroprotective effects in rat models of chemically- and stress-induced gastric ulcers, but no human studies exist to demonstrate efficacy for gut health in people. Animal evidence is limited to a single study.

L-theanine shows plausible mechanisms for supporting gut health through microbiota modulation and intestinal barrier protection, demonstrated consistently in animal models and one human RCT, but robust human clinical evidence remains limited. Efficacy in humans for gut health is not yet proven.

L-tyrosine shows promise for gut health through microbiota remodeling in animal models, particularly for autism-like behaviors, but no human clinical trials exist. Efficacy is plausible based on consistent animal findings but remains unproven in humans.

Acetyl-L-carnitine appears in multiple gut health studies as a microbial metabolite associated with improved intestinal function and immune homeostasis, but direct human evidence of efficacy is limited to observational studies and mechanistic research. One animal study demonstrates therapeutic potential for colitis, but no RCTs in humans have specifically tested ALC for gut health outcomes.

Glycine shows plausible benefits for gut health through animal studies and mechanistic research, but human evidence for direct gut health benefits is sparse and limited to small or observational studies. Most human data focuses on indirect markers (amino acid metabolism, microbiota composition) rather than clinical gut outcomes.

GABA produced by gut bacteria is associated with various health outcomes in observational studies and shows mechanistic promise, but direct evidence that GABA supplementation improves gut health in humans is lacking. Most evidence is mechanistic or involves indirect pathways through the gut-brain axis rather than direct gut health benefits.

Beta-alanine and carnosine show plausible mechanisms for improving gut health through barrier function and microbiota modulation, but human evidence is absent. Animal studies and mechanistic reviews suggest benefits, but efficacy in humans remains unproven.

L-Citrulline shows plausible mechanisms for gut health through arginine biosynthesis and microbiota modulation in observational and animal studies, but lacks direct human RCT evidence demonstrating efficacy for gut health endpoints.

HMB shows promise for gut health markers in limited human studies, primarily through improvements in intestinal barrier function when combined with prebiotics. However, evidence remains preliminary with small sample sizes and inconsistent findings across outcomes.

Taurine shows plausible benefits for gut health through modulation of microbiota composition and barrier function, but evidence is almost entirely from animal models and observational human studies. Only 1 human RCT exists in this dataset, and it focused on fasting effects rather than taurine supplementation per se.

BCAAs show plausible mechanisms for supporting gut health through microbiota modulation and intestinal barrier function, but direct evidence of efficacy for gut health in humans is weak and inconsistent. Most evidence comes from animal studies or mechanistic research; human trials either lack specificity to gut outcomes or show null/mixed results.

L-arginine shows plausible gut health benefits in animal models and small human studies, primarily through nitric oxide metabolism and microbiota modulation, but human efficacy remains unproven with only 5 small RCTs and limited clinical outcome data.

Leucine supplementation shows plausible mechanisms for supporting gut health through microbiota modulation and intestinal barrier function, but human evidence is limited to one small RCT with mixed results. Most evidence comes from animal and in vitro studies.

Tryptophan supplementation modulates gut-brain axis pathways, particularly tryptophan-serotonin metabolism and aryl hydrocarbon receptor activation, but human efficacy data for gut health specifically remain limited to mechanistic studies and small pilot investigations.

L-Serine has been studied primarily in animal models and a single small human phase I trial for neurological conditions, with indirect evidence suggesting potential gut-brain axis benefits through amino acid metabolism. However, no rigorous human trials specifically demonstrating efficacy for gut health have been conducted.

L-lysine supplementation shows plausible mechanisms for gut health based on one recent animal study demonstrating barrier restoration and microbiome modulation, but efficacy in humans remains unproven. Safety data from clinical studies is reassuring but does not establish therapeutic benefit for gut disorders.

Cortistatin shows promise for gut health based on consistent animal studies demonstrating anti-inflammatory effects in colitis models, but no human efficacy trials exist. Evidence is emerging but unproven in humans.

Ghrelin is a gut hormone that increases during weight loss and fasting, but evidence does not demonstrate that ghrelin supplementation or modulation improves gut health. Most research examines ghrelin's role in appetite and metabolism rather than direct gut health outcomes.

Nesfatin-1 shows plausible involvement in gut health through animal studies demonstrating anti-inflammatory, antioxidant, and microbiota-modulating effects, but lacks rigorous human evidence demonstrating clinically meaningful improvements in gut function or disease outcomes.

Neuropeptide Y shows plausible mechanisms for supporting gut health through animal studies and observational human data, but no randomized controlled trials in humans demonstrate efficacy for this specific goal.

Orexin-A shows promise for gut health through mechanisms involving intestinal motility, glucose absorption, and anti-inflammatory effects, but evidence is limited to animal studies and mechanistic reviews with only 2 small human studies that did not directly measure gut health outcomes.

PACAP shows potential mechanisms for supporting gut health through neuropeptide signaling and cytoprotection in animal and in-vitro studies, but no human clinical trials demonstrate efficacy for gut health outcomes.

PYY plays a documented role in appetite regulation and satiety signaling, but direct evidence that PYY supplementation improves gut health outcomes in humans is absent. Most evidence is mechanistic or derived from animal studies; human data is limited to appetite/weight contexts.

Thymopentin shows promising effects on gut inflammation in animal models, particularly in colitis, but lacks human RCT evidence for gut health. Efficacy is plausible based on consistent animal studies but unproven in humans.

NAD+ metabolism is mechanistically linked to gut health and microbiome function, but there is no direct evidence that NAD+ supplementation improves gut health outcomes in humans. Evidence is mostly mechanistic and animal-based.

Calcium supplementation shows mixed evidence for gut health. While some studies demonstrate mechanisms involving gut microbiota modulation and metabolite changes, human evidence is limited to observational studies with small samples, and several large meta-analyses show calcium supplementation causes gastrointestinal adverse events rather than improving gut health.

Folate shows potential for supporting gut health, particularly in reducing intestinal inflammation and maintaining barrier integrity in ulcerative colitis models. However, evidence is limited to one key human observational study and animal models; robust human RCT data for gut health specifically is absent.

Luteolin shows promising anti-inflammatory and antioxidant effects on gut health in multiple animal studies and one human observational study, but efficacy in humans remains unproven. No randomized controlled trials in humans exist.

Ginger shows promising effects on gut health markers in animal models and one small human trial, but efficacy in humans remains largely unproven. Most evidence comes from animal studies demonstrating anti-inflammatory effects and microbiota modulation.

Cinnamon shows plausible mechanisms for gut health benefits through microbiota modulation and barrier function improvements, but evidence comes primarily from animal studies and reviews. Limited human data exists, and the one human RCT on gastric function found no effect.

Lycopene shows promise for gut health through antioxidant and barrier-protective mechanisms in animal and limited human studies, but efficacy in humans remains unproven. Evidence is primarily from animal models with only indirect human safety data.

Sea moss extract shows prebiotic potential in animal and in vitro studies, with evidence that it can modulate gut microbiota composition and increase beneficial bacteria. However, human efficacy for gut health remains unproven—only one human RCT exists, and it was conducted in laying hens, not humans.

Yellow Dock (Rumex species) shows promise for gut health in animal models, with antidiarrheal and anti-inflammatory effects demonstrated across multiple rodent studies. However, no human clinical trials exist, leaving efficacy in humans unproven.

Chlorophyll shows plausible gut health benefits in animal models through microbiota modulation and obesity prevention, but human evidence is limited to a single mechanistic study focused on carcinogen absorption rather than gut health endpoints.

Vitamin A shows plausible mechanisms for supporting gut health through effects on intestinal barrier function and microbiota composition, but human evidence is limited to observational studies without clear proof of efficacy for the primary goal of improving gut health.

Moringa shows plausible benefits for gut health through microbiota modulation and intestinal development in animal models, but human evidence is limited to one small pilot study on breastmilk composition and one acceptability study. Efficacy in humans is not yet proven.

Slippery elm shows potential to modulate gut microbiota composition in one small human RCT, but evidence of actual clinical benefit for gut health is lacking. A second human RCT found no improvement in gastrointestinal symptoms with a multi-ingredient supplement containing slippery elm.

Caffeine shows mixed effects on gut health. While one RCT found it enriched beneficial gut bacteria in athletes, another RCT demonstrated it exacerbates exercise-induced intestinal cell damage, particularly in genetically sensitive individuals. Evidence is limited and contradictory.

GHRP-2 has not been studied for gut health outcomes in humans. The available evidence consists of mechanistic animal studies and one case report, with no demonstration of efficacy for improving gut health, microbiome function, or gastrointestinal disease.

Melanotan 1 is mentioned only as a potential photoprotective agent for polymorphic light eruption, not as a gut health intervention. No evidence exists linking this compound to gut health outcomes.

Humanin is mentioned only as a mitochondrial micropeptide in two review articles discussing broader topics (colorectal cancer biomarkers and lifespan regulation), with no direct evidence of efficacy for gut health demonstrated in any study.

Follistatin 344 has not been directly studied for gut health in any of the available PubMed literature. The two identified studies measure follistatin as a biomarker of myostatin regulation in response to cocoa supplementation and exercise, but make no assessment of gastrointestinal or gut microbiome outcomes.

Only in-vitro testing exists for Thymalin and gut health. The single study used thymalin as a loading test reagent to measure immune responses in children with GI conditions, but did not evaluate thymalin as a therapeutic intervention or demonstrate efficacy for improving gut health.

Bronchogen has only one animal study (rat model of COPD) showing potential effects on bronchial epithelium remodeling and lung inflammation markers. No human efficacy data exists for gut health specifically, and the single study does not directly address the stated goal.

5-Amino-1MQ has been studied only in a single animal model (obese mice) for gut health effects, showing microbiome alterations when combined with diet restriction. No human trials exist, and efficacy for gut health in humans is not demonstrated.

Cerebrolysin's effect on gut health is not assessed in available literature. The single relevant abstract mentions Cerebrolysin only in passing within a systematic review on nutrition and cervical myelopathy, with no data on gut health outcomes.

Only one in-vitro study exists examining ibutamoren (MK0677) in relation to gut health, showing effects on adipocyte lipolysis but with no direct relevance to gastrointestinal health outcomes.

No evidence demonstrates that oxytocin improves gut health in humans. The available literature consists of one mechanistic review touching on ASD comorbidities (not specifically oxytocin) and one in-vitro study on oxytocin peptide absorption in pigs—neither establishes efficacy for the stated goal.

Alpha-lipoic acid has not been demonstrated to improve gut health in humans. The available evidence consists of mechanistic studies in animal models and cell culture showing theoretical benefits for enteric neurons, but no human clinical trials specifically testing gut health outcomes.

Saw palmetto has no demonstrated efficacy for gut health. All identified studies investigate benign prostatic hyperplasia (BPH) and lower urinary tract symptoms in men; none evaluate gastrointestinal or microbiome health outcomes.

MSM has not been studied for gut health in humans; all available evidence comes from animal models (poultry and kittens) showing minimal or no significant effects on gut microbiota and metabolic outcomes. No human efficacy data exists for this indication.

No human evidence exists for ecdysterone and gut health. All 19 studies are mechanistic insect/cell research showing that ecdysone signaling regulates insect midgut development, cell death, and microbiota composition—findings with no demonstrated relevance to human gut health.

Turkesterone has not been proven effective for gut health. The only gut-relevant finding comes from an in-vitro study showing phytoecdysteroids can modulate smooth muscle contractility, but no human efficacy data exists for this goal.

Valerian root has not been studied in human trials for gut health. Available evidence consists only of mechanistic reviews and a single animal study showing bioavailability, with no direct evidence of efficacy for gastrointestinal health.

No evidence exists that kava improves gut health. The two available abstracts address anxiety treatment and intestinal permeability of kavain in cell models, but neither demonstrates efficacy for gastrointestinal health as a primary outcome.

Passionflower is mentioned in a review as a potential modulator of gut microbiota in the context of mood disorders, but no direct evidence of efficacy for gut health is presented. The abstract is incomplete and does not report actual study results.

Methylene blue has not been studied for gut health efficacy in any human trials. References to methylene blue in these abstracts are limited to use as a laboratory marker or procedural tool (detecting H. pylori, measuring gastric H2S), not as a therapeutic intervention for gut health.

Pregnenolone is a steroid hormone precursor studied primarily for its role in gut microbiota-steroid metabolism rather than as a direct therapeutic agent for gut health. No human clinical trials demonstrate efficacy for improving gut health outcomes.

D-ribose has not been studied for gut health efficacy in humans. The available evidence consists of one animal study showing modest microbiota composition changes in sheep and mechanistic reviews discussing pentose metabolism in commensal bacteria, but no clinical trials demonstrating that D-ribose supplementation improves gut health outcomes.

Huperzine A has not been studied for gut health outcomes in humans. The limited evidence consists of mechanistic studies in animals showing gut microbiota changes and one mouse study demonstrating tolerance of gastrointestinal side effects, but no clinical trials or evidence of efficacy for actual gut health improvement.

Only a single animal pharmacokinetics study exists for Noopept and gut health. The study demonstrates that Noopept is absorbed through the gastrointestinal tract and crosses the blood-brain barrier, but provides no evidence of efficacy for gut health outcomes.

Only one human RCT exists for bromantane (ladasten) and gut health, with an abstract that reports use in IBS patients but provides no actual efficacy data, effect sizes, or clinical outcomes. Efficacy is not demonstrated.

DMAE has not been studied for gut health efficacy in any human trials. The evidence consists only of incidental mentions in unrelated studies (a test interference study and arsenic metabolite research) with no direct assessment of gut health outcomes.

Sulbutiamine has not been tested for gut health efficacy in any human or animal studies. A single in-vitro study identified it as a potential antiparasitic agent against microsporidial enzyme targets, but this does not constitute evidence of clinical efficacy for gut health.

D-Aspartic Acid has not been studied for gut health in humans. The limited evidence consists of one in-vitro study showing D-Asp inhibits small intestinal epithelial cell proliferation, animal studies on unrelated metabolic outcomes, and mechanistic studies on bacterial D-amino acid production—none demonstrating efficacy for gut health as a clinical goal.

Evidence for L-carnosine and gut health consists entirely of review articles and animal models with no human clinical trials. While mechanistic pathways are proposed, efficacy in humans remains unproven.

There is no evidence that ornithine supplementation improves gut health. The single available abstract addresses ornithine transcarbamylase deficiency, a rare genetic disorder, and does not evaluate ornithine as a therapeutic intervention for gut health.

Retatrutide has not been studied for gut health as a primary outcome. All available evidence focuses on weight loss, glucose control, and metabolic effects; gastrointestinal side effects are the most commonly reported adverse events, not therapeutic benefits for gut health.

Tirzepatide has not been studied for gut health effects. The available evidence focuses exclusively on weight loss, glycemic control, and cardiometabolic outcomes; no abstracts report data on gut microbiome, intestinal barrier function, digestive symptoms, or other gut-specific health markers.

Cagrilintide has not been studied for gut health. All available evidence concerns its effects on weight loss and glucose control in obesity and diabetes; no abstracts report outcomes related to gastrointestinal health, microbiome, intestinal barrier function, or other gut health markers.

Dulaglutide has not been studied for direct effects on gut health. The single relevant abstract shows dulaglutide increases certain bacterial genera (Bacteroides, Akkermansia, Ruminococcus) associated with metabolic benefits, but this is part of a broader microbiota survey with no measurement of actual gut health outcomes.

Exenatide has not been studied for gut health benefits. All identified research examines gastrointestinal side effects (nausea, vomiting, diarrhea) or uses exenatide as a tool to study unrelated conditions like Parkinson's disease and addiction—not to improve gut function or microbiota in ways that would constitute positive health outcomes.

Lanreotide is a somatostatin analog studied primarily for neuroendocrine tumors and acromegaly, not for gut health. The abstracts provide no evidence that lanreotide improves gut health as a standalone therapeutic goal.

Lixisenatide has not been studied for gut health benefits. All evidence concerns its use for type 2 diabetes and Parkinson's disease; gastrointestinal effects reported are adverse events (nausea, vomiting, diarrhea), not therapeutic benefits to gut function.

P21 is not being studied as a therapeutic intervention for gut health. Both abstracts mention p21 expression only as a mechanistic biomarker of neuroinflammation and neurodegeneration caused by dysbiotic microbiota, not as a treatment.

Pemvidutide has not been studied for gut health in any of the available literature. All evidence relates to weight loss and glycemic control in diabetes/obesity populations; no abstracts demonstrate efficacy for gut health outcomes.

Pramlintide has not been studied for gut health outcomes. All evidence addresses glucose control and gastrointestinal side effects (nausea, delayed gastric emptying) in diabetic patients, not improvements in gut microbiota, barrier function, or overall digestive wellness.

Setmelanotide has not been studied for gut health effects. All available evidence focuses on weight loss in rare genetic obesity syndromes (Bardet-Biedl and Alström syndromes); no abstracts report any measures of gut microbiota, intestinal function, digestive health, or gastrointestinal outcomes beyond tolerability.

SNAP-8 does not appear in any of the 50 gut health abstracts provided. No evidence of efficacy or mechanism is available.

Survodutide has not been studied for gut health specifically. The available evidence shows it reduces body weight and improves blood sugar control, but these studies do not measure gut health outcomes, microbiota, intestinal barrier function, or gastrointestinal health markers.

Teriparatide is an osteoporosis medication with no demonstrated efficacy for improving gut health. The limited evidence discusses gastrointestinal side effects, not therapeutic benefits for the gastrointestinal system.

C-10 (sodium caprate) is studied as an intestinal permeation enhancer for drug delivery, not as a gut health supplement. The evidence does not demonstrate that C-10 improves gut health, microbiota, or barrier function—only that it transiently opens tight junctions to increase drug absorption.

CAAKG (alpha-ketoglutarate) has not been studied for gut health efficacy in humans. Evidence is limited to mechanistic reviews, animal models, and tangential mentions in studies focused on other outcomes.

Manganese has not been studied for efficacy in human gut health. The available evidence consists only of in vitro bacterial studies and animal models in poultry and calves, with no demonstration of clinical benefit in humans.

Vitamin B1 (thiamine) is essential for preventing deficiency-related diseases like Wernicke encephalopathy and beriberi, particularly in malnourished or post-surgical patients. However, the evidence does not demonstrate that B1 supplementation actively improves gut health in healthy individuals or those without deficiency.

Vitamin B5 (pantothenic acid) has not been proven effective for gut health in humans. The only available evidence is from a single 2026 animal study examining endometrial injury in mice, which is not relevant to gut health.

Vitamin B6 has not been demonstrated to improve gut health. The available studies examine markers of intestinal dysbiosis and metabolic dysfunction in autistic children, but do not directly assess or measure gut health outcomes.

No human evidence exists for lecithin's effects on gut health. Available studies are animal models and reviews without direct demonstration that lecithin improves human gut health outcomes.

Vitamin K1 has not been demonstrated to improve gut health. The available evidence shows vitamin K1 is involved in maintaining gut microbiota composition and may be produced by intestinal bacteria, but no studies prove it actively improves gut health outcomes when supplemented.

Lutein has not been demonstrated to improve gut health in any of the available human studies. While one animal study showed lutein protected intestinal barrier function in stressed broilers, and one human trial is investigating potential gut-microbiota interactions, there is no established evidence that lutein supplementation actually improves gut health in humans.

MCT oil has not been demonstrated to improve gut health. While studies show MCT is absorbed differently than long-chain fats and may affect gastric emptying, no evidence demonstrates it provides therapeutic benefit for gut health outcomes.

Zeaxanthin has not been studied for gut health specifically. All identified evidence relates to eye health (AMD), where zeaxanthin may play a role in the gut-retina axis, but no studies demonstrate direct effects on gut health outcomes.

No human evidence exists that beetroot improves gut health. Both available studies are narrative reviews that mention microbiome effects only theoretically or as secondary outcomes, without demonstrating actual efficacy for gut health in any study population.

Apple cider vinegar has not been studied for gut health specifically. The available evidence addresses lipid and glucose metabolism in humans, and microbiota changes in shrimp — neither directly demonstrating efficacy for human gut health.

Kelp (Ascophyllum nodosum) has been studied only in dairy cows for ruminal fermentation effects, with no human trials demonstrating efficacy for gut health. The single available study shows mixed results that do not clearly support a beneficial effect on gut health.

Dandelion root extract shows anti-cancer activity against leukemia cells in laboratory studies, but there is no evidence it improves gut health in humans or any living organism.

Manuka honey shows in-vitro antimicrobial activity against C. difficile and does not harm the gut microbiota in mice, but there is no evidence it actively improves gut health in humans. The evidence is limited to laboratory studies and one animal model with null efficacy findings.

No evidence that DHEA improves gut health. The 8 studies examine DHEA's effects on cancer, fertility, mental health, aging, and steroid metabolism—none directly test gut health as a primary outcome.