Coconut water, the liquid endosperm of green coconuts (cocos nucifera), is a refreshing beverage and a natural rehydration medium. It is also used as a supplement in nutrient media for tissue culture. As it offers higher amounts of electrolytes, such as potassium and magnesium, compared to regular sports drinks, coconut water is known as a ‘natural isotonic sports drink’. Functioning as a prebiotic, coconut water solids support beneficial bacteria in the gut. The endosperm abounds in essential nutrients such as proteins, amino acids, sugars, vitamins, minerals and growth factors. This nourishes the growth of the embryo in green coconuts, and therefore potentially supports healthy cell growth and metabolism in other living tissues as well.

It is important to differentiate between coconut milk and coconut water. The first is a sweet, milky, white looking base taken from the flesh of a fully developed coconut, while the latter is the liquid endosperm of the coconut.

The coconut is unique in that it contains large amounts of liquid endosperm for a year or more of its life. The largest quantity of the liquid endosperm, coconut water, is however, contained in young green coconuts. It delivers vital nutrients for sustained development of the solid endosperm (coconut meat) found inside the fruit. At the completion of growth, the solid endosperm and the last of the coconut water provide nourishment for the forming embryo and seedling. As such, coconut water serves the role as a reservoir of nutrients to support tissue growth.