Efamol Pure Evening Primrose Oil with Rigel Evening Primrose Oil UNIQUE to Efamol to support beautifully smooth & nourished looking skin. Not all evening primrose oils are the same. Efamol's evening primrose oil is unique. It is extracted from a cultivated evening primrose, the seeds of which contain up to 33% more GLA than other oils. GLA is an Omega-6 nutrient found naturally in Evening Primrose oil. Research shows that it isn't just the quantity of GLA that's important - it's the quality. Efamol captures the essence of both.