Holland & Barrett Evening Primrose Oil 1300mg Capsules, Nature is always stepping in heroically to provide us with substances we can’t make ourselves. In the case of the yellow evening primrose wildflower (Oenothera biennis), it’s essential fatty acids linoleic acid and gamma linoleic acid. Holland & Barrett Natural Evening Primrose Oil 1300mg is extracted from the wildflower’s seeds through cold pressing and then enriched with vitamin E and vitamin B6.