Spirulina is a microscopic, blue-green alga which naturally grows in alkaline (salty) lakes. Spirulina is rich in phytonutrients and antioxidants, protein, vitamins and other nutrients. The health benefits of eating Spirulina are well documented in the biomedical literature. Spirulina promotes immune system health and provides important antioxidant benefits. Spirulina contains over 60% protein, higher than any other food! From the Spirulina website.