Evening Primrose Oil

Evening Primrose Oil

Evening Primrose Oil


Evening Primrose is a herb with the botanical name Oenothera biennis. It is also known as King's Cureall.


Oenothera biennis is native to the temperate regions of North America and generally grows in dry areas. The plant is a perennial herb that has a tall, straight, hairy stem and rough, hairy, lance-shaped leaves. Yellow flowers bloom from June to October and the fruit is an oblong-shaped, hairy capsule.

Traditionally, it was the leaves of the Evening Primrose which were used medicinally, but it is now the seeds of Evening Primrose that are harvested and pressed for the oil. The oil contains linolenic acid and gamma-linolenic acid (GLA), which are essential fatty acids. The body converts GLA into special chemicals called prostaglandins, which have a number of important actions in the body, such as regulating inflammation. Essential fatty acids are fats that cannot be produced by the body, so are required in the diet. Essential fatty acids are very important for maintaining cell membranes, regulating inflammation and maintaining a number of metabolic processes. See the Fats or Lipids topic on the Healthpoint for further information about essential fatty acids.


Herbal supplements can alter the effects of certain drugs, including prescription medications. Always tell your Doctor about any prescription medications, non-prescription medications, herbs or other dietary supplements you are taking.
- Evening Primrose Oil should not be used by patients taking anticonvulsants or medication for schizophrenia as Evening Primrose Oil contains gamolenic acid (GLA) that can reduce the 'threshold' level at which seizures occur.
- Evening Primrose Oil can lower blood pressure so may increase the effects of anti-hypertensive medications (i.e. those that reduce blood pressure) and reduce the effectiveness of hypertensive drugs (i.e. those that increase blood pressure).

Medical use

Always consult your Health Professional to advise you on dosages and any possible medical interactions.

Evening Primrose Oil has been found to relieve symptoms of premenstrual syndrome, such as swollen abdomen (fluid retention), tenderness in the breasts, irritability, depression, swollen fingers and ankles. Evening Primrose Oil may block the effects of the hormone prolactin that causes many of the symptoms of premenstrual syndrome.

Evening Primrose Oil has an anti-inflammatory effect and can reduce pain and inflammation associated with rheumatoid arthritis. In some cases, patients have even been able to reduce their dosage of prescription anti-inflammatory medications.

Inflammatory skin conditions like eczema, acne and psoriasis may respond to Evening Primrose Oil supplements, although it may take up to 3 months before there is significant improvement.

Evening Primrose Oil reduces cholesterol levels in patients with hypercholesterolaemia (high serum cholesterol). It also decreases the formation of blood clots by reducing the 'stickiness' of the platelets that are responsible for forming the clots. Evening Primrose Oil reduces blood pressure in patients with hypertension (elevated blood pressure).

DRY SKIN OR Mucous membraneS
Essential fatty acid deficiency may lead to dry skin, dry eyes or Mucous membranes. If dietary intake is inadequate, supplementation with Evening Primrose Oil may be beneficial.

Evening Primrose Oil can improve brain and liver function more quickly in people who have stopped drinking.


Anti-inflammatory, anti-thrombolytic (reduces the formation of blood clots), antioxidant, hypotensive (reduces high blood pressure), hypocholesterolemic (cholesterol-lowering).


- The long-term effects of consuming large quantities of Evening Primrose Oil have not been studied, but it appears there are few toxic effects from short-term use.