The term spirulina refers to a large number of blue-green algae. Both Spirulina and non-Spirulina species are classified as blue-green algae and include: Aphanizomenon spp., Microcystis spp., Nostoc spp., and Spirulina spp. Most commercial products contain Aphanizomenon flos-aquae, Sprirulina maxima, and/or Spirulina platensis. These algae are found in the warm waters of the world, especially in Mexico and central Africa.
Spirulina is different from other blue-green algae because it has a spiral structure. Spirulina spp. are most often grown under controlled conditions and are less likely to be contaminated, compared to naturally harvested non-spirulina species.
Blue-green algae have been used as a source of protein, but may have harmful effects. Spirulina is rich in nutrients and contains up to 70 percent protein, B-complex vitamins, beta-carotene, vitamin E, and numerous minerals. Spirulina has been found to contain more beta-carotene than carrots.
Spirulina has been used since ancient times. It is believed to be useful as an antioxidant, antiviral, anticancer, weight loss aid, and cholesterol-lowering agent.
Blue-green algae and spirulina are sold in health food stores and over the Internet as food supplements in Canada, the United States, and Europe. Possible health benefits include improved digestion, better immune function, and relief from the symptoms of attention deficit hyperactivity disorder (ADHD), allergies, and fatigue. Some of these products may contain harmful compounds and should be used with caution. Blue-green algae also contain compounds called C-phycocyanins, which are used in food and cosmetics, and are known for their antioxidant and therapeutic potential.
The blue-green algae Aphanizomenon flos-aquae is produced in the same location in southern Oregon as the blue-green algae, Microcystis aeruginosais, which may cause cancer or liver damage, and there is a risk of contamination.

Related Terms

AFA, Anabaena spp., Anacystis nidulans, Aphanizomenon flos-aquae, Aphanizomenon spp., Arthrospira maxima, Arthrospira platensis, Artrospira platensis, B-complex vitamins, beta-carotene, BGA, blue-green algae, C-phycocyanin, calcium, calcium spirulan, carotenoids, chlorophyll, copper, cyanobacteria, cyanobacterium, dihe, Dunaliella salina, free fatty acids, iron, Immulina™, klamath, Klamath algae, Klamin®, lead (Pb), Lyngbya majuscule, magnesium, manganese, microcystin-LR, microcystin-RR, microcystins, Microcystis aeruginosa, Microcystis spp., Microcystis wesenbergii, minerals, monogalactosyl monoacylglycerols, Multinal, nickel, Nostoc spp., phenylalanine, phosphatidylglycerols, photolase, phycocyanin, phytoplankton, plant plankton, polar lipids, polysaccharides, pond scum, potassium, prokaryotic cyanobacterium, protein, Selen-Spirulina, sodium, Spirulina-Dunaliella, Spirulina fusiformis, Spirulina fussiformis, Spirulina maxima, Spirulina platensis, Spirulina-Selenium-Sochi, Spiruline, Synechocystis, tecuitatl, sulfated polysaccharides, sulfoquinovosyl diacylglycerols, vitamin E, zeaxanthin, zinc.
Note: Non-Spirulina species, such as Anabaena species, Aphanizomenon species, and Microcystis species, are possibly unsafe because they are usually harvested naturally and may be contaminated. This bottom line includes information about multiple species of blue-green algae, though the focus is spirulina.

evidence table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
High cholesterol (Grade: B)
Early human studies found that spirulina may be effective in lowering cholesterol and triglyceride levels. Spirulina may decrease levels of low-density lipoprotein (LDL or "bad") cholesterol, while increasing levels of high-density lipoprotein (HDL or "good") cholesterol. More research is needed to further confirm these findings.
Allergic nasal symptoms (Grade: C)
Spirulina may have anti-inflammatory effects and may improve nasal allergy symptoms. Spirulina has also been studied for possible effects on the immune system. More high-quality research is needed before a firm conclusion can be made.
Antioxidant (Grade: C)
Spirulina has been studied in runners for possible antioxidant effects. However, further study is needed in this area before conclusions can be made.
Arsenic poisoning (Grade: C)
Spirulina extract plus zinc may be useful for the treatment of arsenic poisoning. More research is needed to confirm these findings.
Attention-deficit hyperactivity disorder (Grade: C)
Spirulina treatment may improve symptoms of attention deficit hyperactivity disorder (ADHD). A combination product that includes spirulina has been found to benefit some ADHD symptoms. More study is needed before conclusions can be made on spirulina use for this condition.
Chronic viral hepatitis (liver inflammation) (Grade: C)
Spirulina is thought to benefit the liver through ant-inflammatory and antioxidant effects. However, early research has found conflicting results on the use of spirulina for chronic viral hepatitis (liver inflammation). More high-quality research is needed before firm conclusions can be made.
Exercise performance (Grade: C)
Early study suggests that spirulina treatment may delay fatigue after a two-hour run. However, more research is needed in this area to confirm these results.
Eye disorders (eyelid twitch) (Grade: C)
Super blue-green algae has been studied for twitches of the eyelids and face. However, early research has found mixed results. Further study is needed in this area.
HIV (Grade: C)
Spirulina supplements have been studied in people with HIV. Early research also suggests that spirulina may decrease the risk of pneumonia infections and increase insulin sensitivity. However, more information is needed in this area before a firm conclusion can be made.
Irritable bowel syndrome (IBS) (Grade: C)
Selenium enriched with spirulina has been used to treat irritable bowel syndrome (IBS) and long-term colon inflammation. Although treatment showed an improvement in symptoms, higher-quality research is needed on the potential effects of spirulina alone.
Malnutrition (Grade: C)
Spirulina has been studied as a food supplement in infant malnutrition. However, results have been mixed. More research is needed in this area.
Menopause (Grade: C)
Klamath algae may improve some symptoms of menopause, including anxiety and depression. Further study is needed before a firm conclusion can be made.
Mouth cancer (Grade: C)
Spirulina has been studied as a possible treatment for oral leukoplakia (plaques in the mouth that may indicate cancer) in people who use alcohol and tobacco. However, more human research is needed before firm conclusions can be made in this area.
Type 2 diabetes (Grade: C)
Early study in people with type 2 diabetes has found that two months of taking spirulina by mouth may benefit blood sugar and cholesterol levels. Spirulina may also increase sensitivity to insulin. However, more research is needed before conclusions can be made on the use of spirulina for blood sugar control in diabetics.
Weight loss (Grade: C)
Spirulina is a popular therapy for weight loss and is sometimes marketed as a "vitamin-enriched" agent that reduces appetite. However, strong evidence is lacking. More research is needed on the use of spirulina for human weight loss.
Chronic fatigue syndrome (Grade: D)
There is currently a lack of strong evidence to support the use of spirulina for chronic fatigue syndrome. Limited research suggests that spirulina may lack benefit over placebo for the treatment of chronic fatigue. More high-quality research is needed in this field.