Spirulina products that are contaminated with toxic metals and bacteria may cause liver damage. Spirulina may also increase symptoms of autoimmune diseases and worsen phenylketonuria, says WebMD.
Spirulina belongs to a diverse group of blue-green algae that are found in salt water and some large freshwater lakes. It is most common in tropical or subtropical waters with high-salt content, reports WebMD.
Certain blue-green algae products are grown naturally, while others are produced in controlled settings. Spirulina grown in a natural setting is more likely to be contaminated and cause serious health risks. Only tested products free from contaminants should be purchased, claims WebMD.
Currently there is not enough research to determine its effectiveness, but spirulina is taken for its source of dietary protein, B vitamins and iron. It is used for weight loss, ADHD, hay fever, PMS and other women's health problems, according to WebMD. It is also used to treat precancerous growths, lower cholesterol, prevent heart disease, and improve digestion and bowel health.
The correct dosage of spirulina depends on a patient's age and health, says WebMD. Currently there is not enough information to determine a completely accurate dosage. Product labels should be read, and a doctor or pharmacist should be consulted before starting use.