Spirulina
A nutrient-dense algae with antioxidant properties.
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What it is
Spirulina is a blue-green algae rich in protein, B vitamins, and antioxidant pigments. It's sold as a 'superfood' powder and in tablets.
How it works
Spirulina is a blue-green algae dense in protein, B vitamins, and antioxidant pigments (like phycocyanin). Its antioxidant and nutrient content is the basis for its 'superfood' marketing, though its clinical effects are modest.
What it's been studied for
Taken as a nutrient-dense antioxidant and general wellness supplement.
What the evidence shows
Some small studies suggest spirulina may modestly improve cholesterol and blood pressure and has antioxidant activity, but the evidence is preliminary and the 'superfood' marketing outpaces the data.
Who should consider it
It's used as a nutrient-dense antioxidant and general wellness supplement; some studies suggest small lipid or blood-pressure effects. Source quality is important, since algae can concentrate contaminants.
Amounts commonly studied
Studies use a wide range, commonly a few grams per day.
How to take it
Studies use a wide range, commonly a few grams per day, as powder or tablets. Choose products from clean, tested sources.
Forms & absorption
Powder or tablets. Source and testing matter, since algae can concentrate contaminants.
Food sources
Spirulina is itself a food (algae), sold as powder or tablets; it isn't otherwise part of a typical diet.
Safety & interactions
Generally safe if sourced from clean, tested suppliers — poorly sourced products can be contaminated with toxins or heavy metals. People with autoimmune conditions or phenylketonuria should check with a provider.
Myths & what it won't do
Myth: spirulina is a miracle superfood. Reality: it's nutrient-dense with some modest lipid and blood-pressure signals, but the marketing outpaces the evidence. Myth: all spirulina is safe. Reality: poorly sourced products can be contaminated with toxins or heavy metals.
Common questions
- Is spirulina worth taking?
- It's nutrient-dense and shows small effects on lipids and blood pressure in some studies, but it's not the miracle its marketing suggests.
- Is it safe?
- Only from clean, tested sources — poorly sourced algae can contain toxins or heavy metals.
- Who should avoid it?
- People with autoimmune conditions or phenylketonuria should check with a provider first.
The amounts listed here are what published research has used — not a prescription or a recommended dose for you. Confirm anything you plan to take with your own healthcare provider, especially if you take medications, are pregnant or nursing, or have a health condition.
Related goals
Research on Spirulina
Recommendations on this page are informed by published research. This is educational information, not medical advice.
- Osadnik T, Goławski M, Lewandowski P, et al. A network meta-analysis on the comparative effect of nutraceuticals on lipid profile in adults. Pharmacol Res. 2022;183:106402. View study →Note: Among the nutraceuticals compared, spirulina ranked favorably for improving lipids, though head-to-head certainty is limited.