For over 30 years spirulina (Arthrospira platensis) has been the premier choice for supplementing a vegetarian diet. Source Naturals Spirulina is a high quality blue green algae which is a high protein, low fat source of numerous vitamins, minerals, carotenoids and essential fatty acids. Spirulina is an excellent source of many nutrients that are hard to maintain at adequate levels with a vegetarian diet. Most notable is the high quality protein, which contains all nine essential amino acids. Spirulina's cell walls do not contain cellulose to slow digestion. Source Naturals Spirulina is naturally grown and harvested without herbicides or pesticides.