Spirulina
Spirulina (Arthrospira platensis)
Spirulina is a blue-green cyanobacterium (Arthrospira platensis) consumed as a dietary supplement for its dense nutritional profile, including complete protein, B-vitamins, iron, and the antioxidant phycocyanin. It is primarily used to support immune function, reduce inflammation, improve lipid profiles, and as a general nutritional supplement for athletes and individuals seeking plant-based protein sources.
Mechanism of Action
Spirulina's bioactivity is largely attributed to C-phycocyanin, a biliprotein pigment that inhibits pro-inflammatory cyclooxygenase-2 (COX-2) activity and scavenges reactive oxygen species (ROS), reducing oxidative stress. It also modulates the immune response by stimulating natural killer cell and macrophage activity, while its polysaccharides (notably calcium spirulan) have demonstrated antiviral and immunomodulatory properties. Additionally, spirulina may improve lipid metabolism by downregulating hepatic fatty acid synthesis and upregulating LDL receptor expression.
Evidence by Health Goal(18 goals)
Dosing Protocols
With meals to improve tolerability and absorption of fat-soluble nutrients
Standard supplemental dose for general health and antioxidant support. Begin at 1g/day and titrate up over 1–2 weeks to reduce initial gastrointestinal discomfort.
With meals, split morning and evening if using higher end of range
Higher dose range used in clinical studies targeting lipid reduction, blood pressure, and athletic performance. Most evidence for cholesterol-lowering and anti-inflammatory effects comes from trials using 4–8g/day.
Safety & Side Effects
Spirulina has a well-established safety profile at doses up to 8g/day in healthy adults, with most adverse effects being mild and transient. However, individuals with autoimmune disorders, phenylketonuria (PKU, due to phenylalanine content), or those taking anticoagulants should exercise caution, and product quality is critical as contaminated spirulina poses real hepatotoxic risk.
Possible Side Effects
- !Gastrointestinal discomfort including nausea, bloating, and diarrhea, particularly at initiation or higher doses
- !Green or blue-green discoloration of stool and urine (harmless, due to phycocyanin pigment)
- !Headache during initial use, possibly related to detoxification or histamine release
- !Allergic reactions including urticaria, rash, or anaphylaxis in rare cases of algae hypersensitivity
- !Worsening of autoimmune conditions due to immune-stimulating effects (e.g., lupus, rheumatoid arthritis flares)
- !Risk of heavy metal or microcystin contamination with low-quality or unregulated products, potentially causing hepatotoxicity
- !Photosensitivity with very high doses in susceptible individuals
Interactions
- -May potentiate anticoagulant and antiplatelet drugs (warfarin, aspirin, clopidogrel) due to vitamin K content and platelet-inhibiting activity — monitor INR closely
- -Additive blood pressure-lowering effects when combined with antihypertensive medications — may require dose adjustment
- -May reduce absorption of certain medications if taken simultaneously due to high fiber and mineral content — space dosing by at least 2 hours from prescription drugs
- -Concurrent use with immunosuppressants (cyclosporine, corticosteroids) may be counterproductive given spirulina's immune-stimulating properties
- -May enhance iron absorption when combined with vitamin C, potentially causing iron overload in individuals with hemochromatosis or those on iron supplementation
Cost & Where to Buy
Cost varies significantly by form (powder vs. tablets/capsules), dose, and brand quality. Certified organic and third-party tested products cost more but reduce contamination risk. Bulk powder is significantly cheaper per gram than encapsulated forms.
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