Evening primrose (Oenothera biennis) is a plant that grows in arid soil – often being one of the first plants to break into tough ground before being out-competed by others. It is also called the sundrop or suncup, but has the name of evening primrose because the flowers of the plant tend to open within one minute, right at the onset of the evening. The oil is the part of the plant most commonly used and sold in stores.
What is evening primrose oil for? Traditionally it is used for two things.
Pregnancy & Menstrual issues
Depending on your source of information, primrose oil is used for everything from easing premenstrual cramping to helping the cervix dilate and prepare for delivery. The methods of applying the oil vary about as much, with some sources claiming you have to ingest it, while others state that it needs to be applied vaginally. Current research, while only preliminary, doesn’t bear out most of these indications.
One thing that we do know is that one of primrose oil’s active compounds is efamol, which has both anticoagulant & anti-platelet properties. In East Asian medicine, this is often translated as a blood moving property, to treat blood stagnation, which is a slowing of blood flow in the small capillaries in the body. From the standpoint of East Asian medicine, many menstrual or pregnancy related problems can be helped by blood moving herbs, but not all problems are helped this way, and using these herbs improperly can be dangerous. It is not surprising that primrose oil gets mixed results in studies – Western research does not yet account for all the factors that define where primrose oil can be effective. Until these are more widely known, you are better off consulting an herbalist if you believe evening primrose oil can be helpful for you.
Primrose oil is also traditionally used to ease bruising and speed the healing of wounds. Research on the effects of primrose oil to treat skin conditions is more promising than that for pregnancy. We know from study that the oil has a very high (~72%) linoleic acid content, which is an essential fatty acid benefiting the skin and hair. And efamol, mentioned earlier, is also helpful in the treatment of atopic eczema.
The East Asian understanding of evening primrose oil, in addition to it’s blood moving qualities, are that it clears heat and toxicity that show up in the skin. This includes conditions like eczema and psoriasis, but can also be more minor and persistent issues like acne. However, the herb must often be combined with others to be most effective for these things.