Sona Evening Primrose Oil 1000mg (90). The oil of the Evening Primrose seed is a rich source of cis-g-linolenic acid (GLA). GLA is an omega 6 fatty acid and is a precursor of a hormone-like substance called PGE1 which has a wide range of beneficial effects in the body.. Sona Evening Primrose Oil 1000mg capsules are made with the highest quality, cold pressed oil, providing a high dose of 1000mg of evening primrose oil in each capsule. Each capsule also contains Natural vitamin E which is an essential vitamin and anti-oxidant to protect cells against oxidative stress/damage