There are no known side effects of contaminant-free spirulina, and it seems to be safe for most people, according to WebMD. Those with certain conditions should avoid spirulina, and all individuals should avoid contaminated spirulina.
Side of effects of contaminated spirulina include nausea, liver damage, stomach pain, shock and death, as stated by WebMD. Contaminated spirulina can be especially harmful to children. It is important to ensure that the spirulina has been verified to have no mycrocystins and other contaminants before consumption.
Only buy spirulina from a reputable brand, warns University of Maryland Medical Center. Though spirulina is not known to interact with any conventional medications, it may possibly interfere with drugs that suppress the immune system.
It is best that individuals with auto-immune diseases avoid using spirulina, according to WebMD. Some of these diseases include rheumatoid arthritis, multiple sclerosis, lupus, and pemphigus vulgaris. Spirulina may worsen symptoms of auto-immune diseases.
Individuals with phenylktonuria should avoid using spirulina, as advised by UMMC. Spirulina contains large amounts of amino acids, including phenylaline.
For pregnant and breast-feeding women, there is not enough information known about the effects of spirulina, adds WebMD. The safest measure is to avoid use until more information is known.