Spirulina (arthrospira platensis) is a unicellular blue alga with a narrow and elongated shape which does not exceed half a millimeter of length. Widespread in brackish waters, it prefers tropical and subtropical areas where it benefits from the alkaline water pH which characterizes them. Despite being in the category of blue algae, spirulina is dark green. This shade is given to it by the presence of chlorophyll, whose pigments cover the bluish reflections of polycyanine and the yellow ones of carotenoids. The name "spirulina" comes from the shape of this seaweed that resembles a spiral. Spirulina alimentary use is very ancient, it seems dates back to the time of the Romans who used it for feeding the African populations. This alga was also present in the diet of the pre-Columbian civilizations, this tradition was reported by the Spanish "conquistador" Cortés. Spirulina is particularly rich in proteins, essential amino acids and lipids. It contains fats that belong to the family of mono- and polyunsaturates, with omega-6 prevailing on omega-3 and high amounts of gamma linolenic acid. If well balanced these nutrients are considered able to improve blood cholesterol levels, triglycerides, normalize blood pressure, participate in the formation of myelin sheaths which line nerves and improve the function of immune system.