GLA (gamma-linolenic acid) is an essential polyunsaturated fatty acid. It is used to produce the soothing intracellular hormonelike messengers known as series 1 prostaglandins (PGE1), which help maintain the balance of many functions in the body. GLA supports the immune system and helps maintain healthy skin and circulation. This essential nutrient is incorporated into our cell membranes, where it helps to maintain fluidity and permeability. Borage seed oil is one of the richest sources of GLA.