Spirulina is the natural product obtained by drying two blue green algae belonging to Phylum cyanobacteria and genus Arthrospira.
These two food supplement grade species A. maxima and a.platensis are commonly called as spirulina.
Spirulina are microscopic, filamentous and free floating and naturally occur in tropical and subtropical water bodies.

The individual algal cells contain gas vacuoles which make them float to the surface of the water body getting better sunlight exposure.
Spirulina thrive well in high pH and high water alkalinity wherein other forms of blue green algae do not survive.
This characteristic helps in raising monocultures of these two species.

Spirulina is cultured throughout the world to get dietary protein supplement for human and animal use.
Commercially spirulina is grown in special culture tanks with proper nutrients to get a slurry of this algae.
The medium for growing spirulina consists of water, sodium bicarbonate, nitrates, sulphates, phosphates, and trace minerals.
This concentrate is then filtered to get a paste which is then spray dried, processed and made into tablets or powder and packed for use.

Nutrients
Spirulina is rich in proteins and make up to 60 to 70% of dry weight. It further contains about 20% carbohydrates, about 5% lipids and about 10% minerals. Spirulina also contains essential amino and fatty acids. Moreover spirulina is a good source of vitamins, minerals and antioxidants.

Proteins
Apart from being rich, spirulina protein is a complete protein containing all the essential amino acids comparable to the proteins in milk, egg and meat. However amino acids lysine, cysteine and methionine are present in slightly reduced proportions. Nevertheless it is better than other legume proteins.

Essential fatty acids
Spirulina is rich in gamma-linolenic acid, an essential fatty acid required in human nutrition.

Vitamins
Spirulina contains B vitamins like B₁, B₂, B₃, B₆, B₉ and B₁₂. It also contains vitamin C, vitamin D and vitamin E. Beta-carotene is abundant in spirulina and is pro vitamin A. Spirulina is the only plant source of vitamin B₁₂ having considerable amounts of this vitamin.

Minerals
Spirulina contains potassium in good proportion. It also contains, chromium, calcium, iron, copper, manganese, magnesium, selenium, zinc, sodium and phosphorus.

Antioxidants
Spirulina contains a variety of phytopigments and nutrients containing antioxidant and anti-inflammatory properties.
Spirulina abounds in Beta-carotene with all mixed carotenoids, half of them being yellow xanthophylls and half being orange carotenes.
These beta carotenes protect our body from free radicals, working against them as antioxidants.

Aging process
As spirulina has easily digestible and concentrated nutrients loaded with antioxidants, it is the best anti-aging food.
The antioxidant nutrients in spirulina neutralise free radicals and certain hormones responsible for aging.
Beta carotene present in spirulina is very good for vision and healthy eyes.
As spirulina reduces the dependence on animal products for proteins the incidental consumption of fats comes down.
The problems connected with aging like arthritis and heart ailments get reduced by foregoing animal products and eating spirulina proteins.

Allergy and Immunity
The anti-inflammatory chemical, interferon production is boosted by the intake of spirulina.
It is believed that spirulina decreases the allergy response by blocking the histamine release from mast cells.
Spirulina increases the activity of bone marrow cells, the production of red blood cells, T-cells and macrophages and boosts the immune system.

Cancer
The immunity enhancing factors and the antioxidants in spirulina give it its anti-cancer effects.
Spirulina also promotes release of tumour necrosis factor alpha, a chemical capable of attacking the tumour cells and fighting against cancer.

Viruses
Spirulina helps in blocking the viral cells from entering the host cells.
Further, recent studies have shown that spirulina extract stops viral cells form replicating.

Heart ailments
Daily consumption of spirulina has been found to lower cholesterol.
It is further discovered that high density cholesterol was increased and low density cholesterol was reduced.
The consumption of spirulina benefits the heart by improving the function of heart arteries and lowers the blood pressure.

Spirulina is being used with success in poor countries for improving the condition of malnourished children.