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Other name(s):

Spirulina fusiformis, Spirulina maxima, Spirulina platensis

General description

Spirulina is a cyanobacteria commonly called blue green algae. It is known for high protein and micronutrient content. Spirulina grows in both fresh and saltwater sources. It includes many species. Common types include Spirulina maxima and Spirulina platensis. Spirulina is grown naturally in America, Central Africa, Asia, and Mexico.

Known nutrients include:

  • Arachidonic acid

  • Gamma-linolenic acid

  • Iron

  • Linoleic acid

  • Phycocyanin

  • Protein

  • Vitamin B-12

Medically valid uses

Spirulina is a source of protein, iron, carotenoids, and some vitamins. The protein in spirulina is like other plant proteins. Like other plant proteins, it’s not complete. This means it doesn’t contain all nine essential amino acids. Because of this, it shouldn’t be used as a main source of protein.

Spirulina has been used as a feed extender for livestock. It can provide some of the total protein intake (up to 25%). But it must be supplemented with amino acids that aren’t in spirulina. These often include lysine, methionine, and histidine. Spirulina protein isn’t digested as well as other livestock foods.

Spirulina can also be used as a source of protein and some vitamins for humans. But it’s important to get it from a tested source. Spirulina can be tainted with microbes and radioactive metal ions. It can also be tainted with heavy metals. These can include mercury, cadmium, lead, and arsenic.

Unsubstantiated claims

There may be benefits that have not yet been proven through research.

Most studies of spirulina have been done on animals, most often mice. Claims are only from animal studies. Spirulina may protect the liver from damage from some types of toxins. It may also reduce allergic reactions. It may do this by calming mast cells. Active mast cells are a source of histamine. This is the agent that causes allergic symptoms. This may strengthen your immune system.

A study with humans suggests spirulina may treat oral cancer.

Dosing format

Follow the instructions on the package for the correct dose. People who are pregnant or breastfeeding should talk to their healthcare providers before taking any supplements. Children shouldn't take spirulina.

Side effects, toxicity, and interactions

Spirulina is a controversial source of vitamin A. It’s been shown to interfere with the body's storage and use of both vitamin A and E. Spirulina is not a good source of vitamin B-12.

Spirulina may interact with some medicines for diabetes and cause blood sugar levels to go too low.

Spirulina might decrease the effect of some immunosuppressants (medicines that decrease the immune system).

If you take warfarin, talk to your healthcare provider before taking spirulina. It may affect how well the blood thinner works.

Online Medical Reviewer: Brittany Poulson MDA RDN CD CDE
Online Medical Reviewer: Heather M Trevino BSN RNC
Online Medical Reviewer: Rita Sather RN
Date Last Reviewed: 8/1/2023