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What is it? Overview Usage Side Effects and Warnings

What is Spirulina?

The supplement called spirulina consists of one or more members of a family of blue-green algae. The name was inspired by the spiral shapes in which these plants array themselves as they grow. 1 Other blue-green algae products are also available on the market, and they are discussed in this article as well.

Spirulina grows in the wild in salty lakes in Mexico and on the African continent. It reproduces quickly, and because the individual plants tend to stick together, it is easy to harvest. Records of the Spanish conquistadors suggest that the Aztecs used spirulina as a food source; we also know that the Kanembu people of Central Africa harvested it from what is now called Lake Chad.

This plant contains high levels of various B vitamins, beta-carotene , other carotenoids, and...

There is no question that spirulina is a nutritious food, but it isn't cheap. 2 Protein can be obtained much more easily and inexpensively from legumes, nuts, grains, and animal foods; iron from dark greens, prunes, and meat; and carotenes and vitamins from standard fruits and vegetables.

Spirulina might have other specific therapeutic uses beyond general nutritional support, but the evidence supporting these recommendations is highly preliminary at best.

Manufacturers of spirulina supplements sometimes claim that the plant can reduce appetite, thereby helping overweight individuals control their food intake. However, one small double-blind study of spirulina for weight loss failed to find a significant difference between spirulina and placebo treatment. 3 One small double-blind...

Safety Issues

Spirulina itself appears to be nontoxic. 4 Studies in rats showed that high spirulina intake caused no weight reduction or toxicity symptoms in rats, nor did spirulina affect the rats' ability to reproduce normally. 5 Nevertheless, there are areas of serious concern for consumers.

Various forms of blue-green algae can be naturally contaminated with highly toxic substances called microcystins. 6 Some states, such as Oregon, require producers to strictly limit the concentration of microcystins in blue-green algae products, but the same protections cannot be assumed to have been applied to all products on the market. Furthermore, the maximum safe intake of microcystins is not clear, and it is possible that when blue-green algae is used for a long time, toxic...