Blue green algae are a group of simple organisms. The two main varieties suitable for human consumption are spirulina maxima and spirulina platensis. Spirulina is often recommended for weight loss and liver detox, though its use for these purposes remains controversial. You should consult your doctor before using blue green algae.
The Encyclopedia of Alternative Medicine explains that blue green algae are a form of cyanobacteria or microscopic organisms that live in fresh water. They obtain their blue color from the protein phycocyanin, and their green color from the green pigment chlorophyll. The two edible types of spirulina grown in warm, brackish water. If the water is polluted, the algae will contain the same substances as the surrounding water. Spirulina that is grown by aquaculture and harvested may contain fewer toxins.
According to "The Encyclopedia of Alternative Medicine," spirulina contains a number of nutrients, such as protein, iron, B vitamins, selenium, magnesium, zinc, bioflavanoids, manganese, beta-carotene, calcium, and gamma-linolenic acid.
According to Medline Plus, blue green algae supplements are used for a number of conditions, including weight loss, seasonal allergies, precancerous growths inside the mouth, increasing energy, improving metabolism, diabetes, stress, depression, fatigue, preventing heart disease, improving digestion, and detoxing the bowels. Unfortunately, there are no current studies to support any of these medical uses.
Weight loss products containing blue green algae generally claim to work because of the phenylalanine content, which is often touted as an appetite suppressant. According to "The Encyclopedia of Alternative Medicine," phenylalanine is not an effective appetite suppressant, and there is no evidence to support that spirulina can aid weight loss.
According to the University of California at Berkeley, after a recent court hearing in California, blue green algae marketers were warned to stop making health claims about their products. Blue green algae harvested from lakes have been found to be contaminated with toxins such as heavy metals.
Stephen Barrett, M.D., warns that over the past three decades, a number of companies, including Microalgae International Sales Corp., and K.C. Laboratories, have been charged and fined for making false claims about spirulina. Such claims include that spirulina is a “superfood,” and that it "works to cleanse and detoxify the body.”