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Evening primrose oil is the oil derived from the seeds of the evening primrose (Oenothera biennis) plant. It has a number of popular uses and is widely available in supplement form.

One of the most important ingredients in evening primrose oil is gamma-linolenic acid (GLA), which is also found in other plant-based oils.

The recommended dose of evening primrose oil is 8 to 12 capsules a day, at a dose of 500 milligrams per capsule.

A range of evening primrose oil products are available for purchase online.

Fast facts on evening primrose oil:

  • Often abbreviated to EPO, evening primrose oil is a rich source of omega-6 essential fatty acids.
  • Evening primrose oil contains linoleic acid as well as GLA - both are essential components of myelin, the protective coating around nerve fibers, and the neuronal cell membrane.
  • Commercial preparations of evening primrose oil are typically standardized to 8 percent GLA and 72 percent linoleic acid.
  • EPO is thought to help a wide variety of conditions including eczema, nerve pain, and osteoporosis.

There are many potential uses for evening primrose oil, including the following:

Evening primrose oil for menopause and premenstrual syndrome

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Evening primrose oil has many therapeutic uses.

Hot flashes experienced by women going through the menopause have a number of non-hormonal treatment options, but, according to the evidence, evening primrose oil does not have an effect.

Some women report PMS symptoms being eased by evening primrose oil, for instance, breast tenderness, feelings of depression, irritability, and swelling and bloating from fluid retention.

However, there is no current evidence to support a role for evening primrose oil in easing premenstrual syndrome (PMS).

Evening primrose oil for nerve pain

Nerve pain associated with diabetes has been treated with evening primrose oil, when conventional treatments have not worked or have been unsuitable.

Beneficial results have been shown in clinical trials, and taking evening primrose oil for 6-12 months may improve the symptoms of nerve damage caused by diabetes.

In one small randomized trial published in Diabetic Medicine, for example, there was a statistically significant improvement in neuropathy scores, including nerve conduction tests, for people taking evening primrose oil capsules for 6 months compared with placebo.

Evening primrose oil for osteoporosis

Evening primrose oil is taken with fish oil and calcium by older adults with osteoporosis; the combination seems to decrease bone loss and increase bone density.

More research is needed to determine the role evening primrose oil itself might play independently of the other supplements.

Evening primrose oil for eczema

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Eczema is sometimes treated with evening primrose oil

Treatment with oral evening primrose oil may help correct an abnormality in essential fatty acids found in eczema.

Eczema can be effectively treated with conventional medicines, but complementary alternatives, such as evening primrose oil are sometimes tried by people whose conditions do not improve as much as they would like, or who fear side effects.

However, a well-respected review of the evidence, conducted by the Cochrane Collaboration, concludes that evening primrose oil is no more effective than placebo at treating eczema, and can produce mild, temporary, mainly gastrointestinal side-effects.

Scleroderma and Raynaud's phenomenon

Scleroderma is an autoimmune disease of the connective tissue characterized by thickening and hardening of various tissues, including the skin and other organs.

Raynaud's phenomenon - which can cause the fingers to go numb and cold - is sometimes associated with scleroderma.

Evening primrose oil has been investigated as a treatment in a number of studies; however, all the studies so far have been small. Further research is needed before the oil can be recommended.

Evening primrose oil for other conditions

Herbal remedies tend to be associated with numerous health claims because the regulation of these products is less rigorous than for prescription drugs.

Many conditions are said to be eased by evening primrose oil. The following lack any supporting evidence:

The following conditions have "insufficient evidence" to support evening primrose oil as a treatment: chronic fatigue syndrome, diaper rash, dry eyes, dyslexia, dyspraxia, ichthyosis, infant development, pregnancy complications, rheumatoid arthritis, schizophrenia, Sjogren's syndrome, ulcerative colitis, cancer, acne, multiple sclerosis, heart disease, and Alzheimer's disease.

In Britain, evening primrose oil used to be approved for treating eczema and breast pain. However, in 2002, the drug regulator concluded there was not enough evidence of the effectiveness of evening primrose for these uses.

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Due to its blood thinning effect, evening primrose oil is not suitable for patients using aspirin or other blood thinning medications.

There are some potential dangers to EPO:

It is possible to be allergic to EPO or its forms. The FDA does not monitor supplements and care should be given to choosing a brand that is know for purity, accuracy of dose, and quality.

Drug interactions bleeding

There is a blood-thinning effect with evening primrose oil, so there is a higher risk of bleeding for people taking the blood thinner warfarin. Therefore, these patients should not use the oil.

Other drugs that thin the blood may also be a problem taken alongside the oil, including clopidogrel and aspirin.

Seizures

People with epilepsy or other seizure disorder should avoid taking evening primrose oil as it may increase the chances of having a seizure. Also, people with schizophrenia treated with certain drugs may be at risk of seizure, so medical advice should be sought.

Anesthesia

Evening primrose oil should not be taken within 2 weeks of going for a general anesthetic because of the increased seizure risk.

Evening primrose oil products are available for purchase in health stores and online.