These claims are bunkum. The FDA has concluded that there is no evidence that spirulina (or phenylalanine) is effective as an appetite suppressant. The FDA has also noted that the "65% protein" claim is meaningless because, taken according to their label, spirulina products provide only negligible amounts of protein.

In 1982, Microalgae International Sales Corp. (MISCORP) and its founder, Christopher Hills, agreed to pay $225,000 to settle charges that they had made false claims about spirulina. The company had claimed that its spirulina products were effective for weight control and had therapeutic value against diabetes, anemia, liver disease, and ulcers.

Light Force, also founded by Hills, marketed spirulina products with claims that they can suppress appetite, boost immunity, and increase energy. Company sales materials claimed that spirulina is a "superfood" and "works to cleanse and detoxify the body." In a 1987 issue of Light Force's magazine, The Enlightener, vice president and corporate attorney Steve Kochen spells out the company's "legal guidelines." These include:

Results of Health Canada's market survey testing of blue-green algal products show that no microcystins were detected in products made from only one type of blue-green algae, Spirulina blue-green algae, which is generally harvested from controlled ponds.

However, testing indicates that for many non-Spirulina blue-green algal products, harvested from natural lakes, consumption according to manufacturers directions results in a daily intake of microcystins above that considered acceptable by Health Canada and the World Health Organization. Microcystins are toxins which accumulate in the liver and can cause liver damage. They are naturally produced by some kinds of blue-green algae. Blue-green algal products are sold in tablet, capsule, or powder forms as food supplements, often as a natural source of minerals.