spirulina

Spirulina is a blue-green algae (a cyanobacterium, usually the species Arthrospira platensis or A. maxima) that is dried and sold as a powder, tablet, or capsule. It is naturally high in protein and also contains vitamins, minerals, and plant pigments, which is why it is marketed both as a food and as a nutritional dietary supplement.

There is no dedicated NIH Office of Dietary Supplements or NCCIH fact sheet for spirulina, and it does not appear in NCCIH's "Herbs at a Glance" series, so authoritative US-government evidence on its specific health effects is limited. US health authorities note generally that dietary supplements are not required to be tested for effectiveness the way prescription drugs are, and that a "natural" label does not by itself mean a product is proven to work or is safe. On the basis of these government sources, we do not have strong evidence that spirulina treats, cures, or prevents any disease.

No authoritative US-government dose has been established for spirulina, and commercial products vary widely in their suggested amounts. Because supplement quality is not guaranteed and these products are not tested the way medicines are, talk to a doctor, pharmacist, or other qualified clinician before starting spirulina, especially if you are pregnant, breastfeeding, taking medications, or managing a health condition.

Authoritative government sources reviewed here do not provide a spirulina-specific safety assessment, so its safety profile is not well characterized in those materials. A widely noted general concern with blue-green algae products is the possibility of contamination during growing or processing — for example with toxins such as microcystins, or with heavy metals or bacteria — so product quality and sourcing matter. Following the broader government guidance for herbal and dietary supplements, do not assume "natural" means safe, and tell your healthcare provider about any spirulina you take.

Side effects of spirulina are not characterized in dedicated NIH or NCCIH materials. As with many supplements, some people may experience mild digestive upset, and poorly sourced or contaminated products could carry additional risk; stop use and seek medical advice if you have an unexpected or concerning reaction.

There is no spirulina-specific interaction guidance from the government sources reviewed here. As a general rule, MedlinePlus cautions that dietary supplements and herbal products can interact with prescription and over-the-counter medicines, sometimes in ways people do not expect, so review spirulina with a pharmacist or clinician before combining it with any medication.