Spirulina refers to a large number of cyanobacteria, or blue-green algae.
It contains unusually high amounts of protein, between 55 and 77% by dry weight, depending upon the source. It is also complete protein–meaning it contains all 9 essential amino acids.
In addition to proteins, spirulina is rich in vitamins, (providing more beta-carotene tha carrots), minerals, polysaccharides and fatty acids including gamma-linolenic acid (GLA), and also provides alpha-linolenic acid (ALA), linoleic acid (LA), stearidonic acid (SDA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA).
Spirulina has been proposed by both NASA (CELSS) and the European Space Agency (MELISSA) as one of the primary foods to be cultivated during long-term space missions.