Medically reviewed on June 7, 2018
What is Spirulina?
Spirulina, a blue-green algae, consists of microscopic, corkscrew-shaped filaments and is found in Africa and Asia, as well as in Central America. Free growing, spirulina lives in high-salt alkaline water in subtropical and tropical areas, sometimes dense enough to give the water a dark-green color. It is commercially grown in the US and has been proposed as the primary foodstuff to be cultivated during long-term space missions because it withstands extreme conditions. Because few other algae grow in salty alkali water, contamination of open pond cultures of spirulina by other microorganisms is usually slight, with the alga growing as a relatively pure culture.
Arthrospira platensis and Arthrospira maxima
Spirulina, dihe, tecuitlatl
What is it used for?
Spirulina has been described in literature since the 16th century. Spanish explorers observed the Aztecs harvesting a blue mud that probably consisted of spirulina. The mud, which was dried to form chips or flavored loaves, was obtained from Lake Texcoco in Mexico. Spirulina was similarly harvested by natives of the Sahara Desert, where it was known as dihe, approximately 10,000 km away.
Spirulina is sold in the US as a health food or supplement. Diverse claims exist for its immune stimulation, cholesterol-lowering, antiviral, and anticancer effects; however, there is limited evidence to support these uses.
What is the recommended dosage?
Doses in clinical studies have ranged from 1 to 10 g/day.
A rare metabolic genetic disorder, phenylketonuria; however, this has not been substantiated.
Safety and effectiveness in pregnancy and lactation is unknown. Because of possible mercury and other heavy metal contamination, spirulina should be avoided during pregnancy.
None well documented.
Few reports of adverse reactions are available. However, spirulina-associated liver toxicity and reactions from heavy metal contamination are possible.
Spirulina is considered nontoxic to humans at usual levels of consumption; however, information is limited.