Evening Primrose Oil

What is it?

Evening Primrose oil was first used by native Americans to heal wounds. It is taken from the roadside plant oenothera biennis. One of the active ingredients found in the seed is gamma linolenic acid (GLA), an essential fatty acid which is broken down and converted into prostaglandin E1 (PGE1). The body needs prostaglandins to regulate a number of key biochemical functions such as increasing blood flow, decreasing blood clotting or reducing swelling. GLA is not manufactured by the body; it has to be ingested from an external source such as evening primrose oil which contains high amount of GLA.

Many things including cholesterol, sugar, high intake of alcohol, ageing, saturated fat, excessive carbohydrate intake or conditions such as diabetes, stress, cancer, viral infections or zinc deficiency can hinder the transformation into GLA hence the benefit of supplementation of evening primrose oil which enters the body as GLA.



The following clinical trials show that evening primrose oil can be useful in the treatment of arthritis.

- Darlington LG, Stone TW. Antioxidants and fatty acids in the amelioration of rheumatoid arthritis and related disorders. Br J Nutr 2001 Mar;85(3):251-69
- Belch JJ, Hill A. Evening primrose oil and borage oil in rheumatologic conditions. Am J Clin Nutr 2000 Jan;71(1 Suppl):352S-6S


- Brown AC. Lupus erythematosus and nutrition: a review of the literature. J Ren Nutr 2000 Oct;10(4):170-83

"Possible beneficial dietary compounds include vitamin E, vitamin A (beta-carotene), selenium, fish oils (omega-3 polyunsaturated fatty acids), evening primrose oil, flaxseed, a plant herb (Tripterygium wilfordii)."

Antioxidant properties

- Birch AE, Fenner GP, Watkins R, Boyd LC. Antioxidant properties of evening primrose “Seed extracts. J Agric Food Chem 2001 Sep;49(9):4502-7

The extracts of evening primrose seeds have great antioxidant activity.

Pre-menstrual Syndrome

- Hardy ML, Herbs of special interest to women. J Am Pharm Assoc (Wash) 2000 Mar-Apr;40(2):234-42.

"Evening primrose oil and chaste tree berry may be reasonable treatment alternatives for some patients with PMS"

- Campbell EM, Peterkin D, O'Grady K, Sanson-Fisher R. Premenstrual symptoms in general practice patients. Prevalence and treatment. J Reprod Med 1997 Oct;42(10):637-46

"When women were asked to nominate up to three treatments they had tried and found most effective, the most commonly mentioned were dietary changes, evening primrose oil, vitamins (including B6) and exercise"

Hyperactivity (ADHD), dyslexia and dyspraxia

Evening primrose oil is believed to benefit children with ADHD, however its efficacy remains anecdotal due to the lack of research.

- Arnold LE, Pinkham SM, Votolato N. Does zinc moderate essential fatty acid and amphetamine treatment of attention-deficit/hyperactivity disorder?
J Child Adolesc Psychopharmacol 2000 SUMMMER;10(2):111-7

If upheld by prospective research, this post-hoc exploration suggests that zinc nutrition may be important for treatment of ADHD even by pharmacotherapy, and if Efamol benefits ADHD, it likely does so by improving or compensating for borderline zinc nutrition.

- Stordy BJ. Dark adaptation, motor skills, docosahexaenoic acid, and dyslexia. Am J Clin Nutr 2000 Jan;71(1 Suppl):323S-6S

"movement skills in a group of 15 dyspraxic children improved after 4 mo of supplementation with a mixture of high-DHA fish oil, evening primrose oil, and thyme oil...The studies were small and had designs that did not allow firm conclusions to be made"

Skin disorders

-Yoon S, Lee J, Lee S. The therapeutic effect of evening primrose oil in atopic dermatitis patients with dry scaly skin lesions is associated with the normalization of serum gamma-interferon levels. Skin Pharmacol Appl Skin Physiol 2002 Jan-Feb;15(1):20-5

"After the treatment, the extent of the skin lesions and the pruritus were markedly reduced in all patients"


- Engler MM. Comparative study of diets enriched with evening primrose, black currant, borage or fungal oils on blood pressure and pressor responses in spontaneously hypertensive rats. Prostaglandins Leukot Essent Fatty Acids 1993 Oct;49(4):809-14

The results suggest that GLA-enriched oils may inhibit the development of hypertension.


- Fukushima M, Ohhashi T, Ohno S, Saitoh H, Sonoyama K, Shimada K, Sekikawa M, Nakano M. Effects of diets enriched in n-6 or n-3 fatty acids on cholesterol metabolism in older rats chronically fed a cholesterol-enriched diet. Lipids 2001 Mar;36(3):261-6

"The results of this study demonstrate that both n-6 fatty acid and n-3 fatty acids such as gamma-linolenic acid and alpha-linolenic acid inhibit the increase of serum total cholesterol"

How to obtain Evening Primrose Oil

Sympathetic GPs will prescribe evening primrose oil; otherwise it is easily obtainable in most chemists in capsule and sometimes tablet form. There is huge variation on the market so it is wise to look carefully at the active ingredients and compare relative strength and price.

Cautions: evening primrose oil is said to aggravate temporal lobe epilepsy and it is generally not advised for use during pregnancy.

Conditions that Evening Primrose Oil may be useful for

Alzheimer's disease
Celiac disease
Chronic fatigue syndrome
Crohn's disease
Cystic fibrosis
Digestive problems
Heart diseases
Immune functions
Irritable bowel syndrome (IBS)
Multiple sclerosis
Pre-menstrual stress
Raynaud's syndrome
Sjögren's syndrome


These are some of the references that have been passed to us; the list is not exhaustive. We have not necessarily read the books, and cannot say how easy it will be to get them.

- Erasmus U. Fats that heal, fats that kill: The Complete Guide to Fats, Oils, Cholesterol and Human Health. ISBN: 0920470386
- Graham J. Evening Primrose Oil ISBN: 0892812885
- Reinagel M. Secrets of Evening Primrose Oil ISBN: 0312972989

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