Spirulina is a natural “algae” (cyanbacteria) powder that is incredibly high in protein and a good source of antioxidants, B-vitamins and other nutrients. When harvested correctly from non-contaminated ponds and bodies of water, it is one of the most potent nutrient sources available. It is largely made up of protein and essential amino acids, and is typically recommended to vegetarians for its high natural iron content. It is often touted for its high B-12 content, though there is a lot of debate about if this particular form is a complete and absorbable form of B-12 and I don’t recommend it completely in place of animal products.
The high concentration of protein and iron also makes it ideal during pregnancy, after surgery, or anytime the immune system needs a boost.