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Other name(s):

Spirulina fusiformis, Spirulina maxima, Spirulina platensis

General description

Spirulina is a primitive single-celled algae. It grows in the ocean. It includes many species. Common ones include Spirulina maxima and Spirulina platensis. Spirulina is cultivated as feedstock in Africa and Mexico.

Known ingredients include:

  • Arachidonic acid

  • Gamma-linolenic acid (GLA)

  • Iron

  • Linoleic acid

  • Phycocyanin

  • Protein

  • Vitamin B-12

Medically valid uses

There are no known medical uses for spirulina in humans. It’s a source of protein, iron, carotenoids, and some vitamins. The protein in spirulina is comparable to other plant proteins. Like other plant proteins, it’s incomplete. This means it doesn’t contain all nine essential amino acids.

Spirulina has been used as a feed extender for livestock. It can provide a percentage 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. However, it’s important to consume a tested source. Spirulina can be contaminated with microbes and radioactive divalent and trivalent metal ions. It can also be contaminated with heavy metals. These can include mercury, cadmium, lead, and arsenic.

Since spirulina is an incomplete protein, it shouldn’t be used as a main source of protein.   

Unsubstantiated claims

Please note that this section reports on claims that have not yet been substantiated through studies.

Most studies of spirulina have been done on animals, especially mice. Claims are only due to animal studies. Spirulina is said to act as a hepatoprotectant. This means it protects the liver from damage from certain toxins. It may also reduce allergic reactions by stabilizing mast cells. Activated mast cells are a source of histamine. This is the agent that causes allergic symptoms. This may strengthen your immune system.

One study with humans suggests spirulina may treat oral cancer.

Dosing format

Follow the instructions on the package for the correct dose. Women who are pregnant or breast-feeding should talk to their healthcare providers before taking any supplements.

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 reliable source of vitamin B-12.

People taking warfarin should talk to their healthcare providers before taking spirulina. It may affect how well the blood thinner works.

Medical Reviewers:

  • Poulson, Brittany, RD, CDE
  • Wilkins, Joanna, R.D., C.D.