Spirulina is an organism that grows in both fresh and saltwater. It is a type of cyanobacteria, which is a family of single-celled microbes that are often referred to as blue-green algae. Just like plants, cyanobacteria can produce energy from sunlight via a process called photosynthesis.

Spirulina was consumed by the ancient Aztecs but became popular again when NASA proposed that it could be grown in space for use by astronauts. This tiny alga is packed with nutrients. A single tablespoon (7 grams) of dried spirulina powder contains:

• Protein: 4 grams
• Vitamin B1 (thiamine): 11% of the RDA
• Vitamin B2 (riboflavin): 15% of the RDA
• Vitamin B3 (niacin): 4% of the RDA
• Copper: 21% of the RDA
• Iron: 11% of the RDA
• It also contains decent amounts of magnesium,
  potassium and manganese and small amounts of almost every other nutrient that you need.

Taken one hour before meals, Spirulina powder can naturally promote the feeling of fullness and prevent over­eating. Rich, complete and digestible protein source. Spirulina powder is very rich in protein (60-70%), containing 18 amino acids including all essential amino acids.

Phycocyanin is the main active compound in spirulina. Research shows this may have antioxidant, pain-relief, anti-inflammatory, and brain-protective properties. 

There is some weak evidence that spirulina can aid in the treatment of high cholesterol and type 2 diabetes. Other claims, including spirulina's anti-allergy and anti-cancer effects, have yet to be proven.

Spirulina is generally safe for use but may cause allergy, headaches, insomnia, muscle pain, and sweating in some. Spirulina should be avoided in pregnant or nursing people, people with autoimmune diseases or on immunosuppressants and those with phenylketonuria.