Spirulina, always a Persian staple, contains an unusually high amount of protein, between 55% and 77% by dry weight, depending upon the source. It is a  complete protein, containing all  essential amino acids, superior to typical plant protein, such as that from legumes.

Spirulina is rich in  gamma-linolenic acid (GLA), and also provides  alpha-linolenic acid (ALA),  linoleic acid (LA),  stearidonic acid (SDA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), arachidonic acid (AA).

Spirulina contains vitamin B1 thiamine, B2 riboflavin, B3 nicotinamide, B6pyridoxine, B9 folic acid,  vitamin C,  vitamin D, vitamin E.

Spirulina is a rich source of  potassium, and also contains  calcium,  chromium, copper,  iron,  magnesium, manganese, phosphorus,  selenium,  sodium, and zinc.

Spirulina contains many pigments including  chlorophyll-a,  xanthophyll,  beta-carotene, echinenone,  myxoxanthophyll,  zeaxanthin,  canthaxanthin,  diatoxanthin, hydroxyechinenone,  beta-cryptoxanthin,  oscillaxanthin, plus the phycobiliproteins , c-phycocyanin,allophycocyanin.

Spirulina extract inhibits  HIV replication in human  T-cells, peripheral blood mononuclear cells PBMC, and  Langerhans cells.

Spirulina helps prevent heart damage caused by  chemotherapy using Doxorubicin, without interfering with its anti-tumor activity. Spirulina reduces the severity of strokes and improves recovery of movement after a stroke; reverses age-related declines in memory and learning; and prevents and treats hay fever.

Spirulina is effective for the clinical improvement of  melanosis and keratosis due to chronic arsenic poisoning; improves weight-gain and corrects anemia in both HIV-infected and HIV-negative  undernourished children; and protects against hay fever.

A 2007 study found that 36 volunteers taking 4.5 grams of spirulina per day, over a six week period, exhibited significant changes in cholesterol and blood pressure: (1) lowered total cholesterol; (2) increased HDL cholesterol; (3) lowered triglycerides; and (4) lowered systolic and diastolic blood pressure.

Spirulina has also been found to be clinically effective against allergic rhinitis, a condition that can lead to chronic sinusitis.