Proteins

Spirulina

Also called: spirulina, blue-green algae, Arthrospira

A blue-green alga, dried into powder, rich in protein and some vitamins.

Why people take it
Nutrition, energy, cholesterol.
What the evidence says
Small studies show modest cholesterol drops.
How it is usually taken
Usually 1 to 8 g a day as powder or tablets; buy products tested for microcystin toxins and heavy metals.
Be careful
Contaminated products can contain liver toxins (microcystins) or heavy metals; buy tested brands. Avoid with autoimmune disease or PKU.
Medicines it can interact with
May reduce the effect of immune-suppressing medicines and add to blood-thinner effects.

Other proteins

Whey proteinCasein proteinPlant protein powderEgg white proteinHMBGelatinChlorella

Common questions

What is Spirulina?

A blue-green alga, dried into powder, rich in protein and some vitamins.

Why do people take Spirulina?

Nutrition, energy, cholesterol.

Does Spirulina work?

Small studies show modest cholesterol drops.

How much Spirulina do people take?

Usually 1 to 8 g a day as powder or tablets; buy products tested for microcystin toxins and heavy metals.

Is Spirulina safe?

Contaminated products can contain liver toxins (microcystins) or heavy metals; buy tested brands. Avoid with autoimmune disease or PKU.

Does Spirulina interact with medicines?

May reduce the effect of immune-suppressing medicines and add to blood-thinner effects.

Sources and further reading

Last reviewed 31 October 2026. Written by Satya Babu.

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For information only, not medical advice. Supplements are not medicines: they are not tested and approved like drugs before they are sold, and they can interact with medicines. Talk to your doctor or pharmacist before you start one, especially if you are pregnant or breastfeeding, take regular medicines, or have kidney, liver or heart disease.