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Uses of Evening Primrose Oil | Benefits, Side Effects & Dosage

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Your Guide to Evening Primrose Oil:


Evening primrose oil seems to be a superb supplement. It’s extracted as oil from the seeds of the herbaceous evening primrose plant, Oenothera biennis L., Onagraceae. The use of evening primrose oil as a dietary supplement is broad across the general population for a variety of proposed benefits. These include: treatment of joint conditions (such as rheumatoid arthritis), eczema and psoriasis, and weight loss(1).

However, the list doesn’t stop there. People use evening primrose oil for a host of other conditions, such as multiple sclerosis(2), osteoporosis(3), Raynauds syndrome(4), cardiovascular disease/ hypertension(5-6); and even cancer(7). However, it’s generally considered that the predominance of research is preliminary in nature and needs to be further substantiated(8-9).


What Does Evening Primrose Oil Do?

The ingredient which makes Evening Primrose Oil a great choice as a supplement is its high content of polyunsaturated fatty acids (PUFAs), specifically gamma-linoleic acid(10).

Interestingly, evening primrose oil has a 74% content of linoleic acid and only 9% gamma-linoleic acid (GLA), however, the latter is What does Evening Primrose Oil do?considered the key active ingredient in the oil(11). The oil has one of the highest concentrations of this substance whereas most herbs and plants don’t contain any.

GLA is an example of an omega-6 fatty polyunsaturated fatty acid and shares a similar structure to omega-3 fatty acids. Omega-6 and omega-3 fatty acids are well known for being highly present in fish oils and include the compounds eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Research has found that the health benefits of such oils are likely to be expansive, including reduction of cardiovascular disease risk factors, anti-inflammatory and anti-oxidant effects, reduction of depression, and disease modification in arthritis(12), which makes evening primrose oil a great addiotion to any healthy lifestyle.

Benefits of Evening Primrose Oil

Evening primrose oil is used to help manage a plethora of different diseases and ailments. We’ve compiled the research into evening primrose oil and whittled it down to some specific areas where the evidence is either the most abundant or most intriguing.

evening primrose oil

1. Joint Health

 A lot of research has been undertaken to examine the effect of evening primrose oil (or its principle ingredient GLA) in rheumatoid arthritis (RA). This is a form of arthritis which is characterised by chronic joint inflammation as a result of the overproduction of inflammatory mediators and reduced oxidative joint-defence mechanisms.

It has been shown that GLA-rich oils may provide an effect which reduces not only inflammatory processes, but also reduces antioxidant activity and reduces the growth of new blood vessels(13-14).

The activity of reactive oxygen species (free radicals) has been considered one of the provocative factors for autoimmune diseases such as RA. Consumption of evening primrose oil has been shown to reduce inflammation and oxidative stress from free radicals by increasing the amount and effectiveness of antioxidant enzymes, to the extent that disease activity in RA is reduced(14-15).

This would subsequently result in reduced symptoms (such as pain and stiffness) and lead to better mobility and function in those suffering from RA.


2. Eczema and Psoriasis

Evening primrose oil has long been used for the treatment of atopic eczema (also called atopic dermatitis) and psoriasis. This led to the large research group, the Cochrane Library, performing a large literature review to examine the effects of evening primrose oil on this condition(16).

Despite widespread use of this supplement for skin conditions such as these, the study actually found that evening primrose oil showed minimal to no effect on the significant reduction of the condition.

However, a more recent pilot study from 2014 contradicts the results of the Cochrane review and shows benefits on disease activity in atopic eczema(17). In fact, they found that the reduction in the intensity of the skin symptoms reduced correlated with the individual increase in GLA levels seen in the participants.

 As such, they suggested that the degree of GLA plasma increase may help predict whether a person may be more likely to respond to evening primrose oil therapy. This is supported by further evidence(18), which shows that in children and adolescents both a dose of 160mg and 320mg are equally effective in treating atopic eczema and that the response is dose dependent (a greater dose means a greater change in symptoms).

The results of this study suggest that the 320 mg and 160 mg groups may be equally effective in treating atopic dermatitis patients and show dose-dependent effects on serum fatty acid levels and EASI scores. This contradictory evidence to the Cochrane results perhaps indicates that the use of evening primrose oil is not generically useful, but perhaps that some people are more likely to benefit than others.


3. Weight Loss

The holy grail of supplements is a supplement that aids weight loss. Anything we can consume which may assist in the loss of body fat is often found to be a popular product. However, despite people often singing the praises of evening primrose oil for this task, the benefits are not as clear and consistent as you may expect.

For example, a double-blind study on 100 significantly overweight women examined the benefit of evening primrose oil supplementation over 12-weeks and compared to a placebo supplement(19). This study showed no difference between groups, meaning evening primrose oil was only as effective as a placebo tablet. However, this trial was flawed methodologically by a 25% drop out rate, which would substantially impact the reliability of the results. The subject pool also consisted of a group of women who had failed to respond previously to other forms of treatment, leading them to be considered to have “refractory obesity”. Simply put, this is a form of obesity which is considered to be resistant to treatment(20).

 Another double-blind randomised trial examined whether evening primrose oil therapy may have an influence only on those who had a family history of obesity(21). These results indicated a significant loss of weight in those who did have a family history, particularly if both parents were obese. This perhaps indicates a genetic component on the likely effectiveness of evening primrose oil on weight loss.

Considering the contradictory results from these studies, it’s clear that more research is necessary to determine whether evening primrose oil is really useful for weight loss.


4. Migraines

A final area where evening primrose oil is often used as a therapy is in the treatment of headaches, specifically migraines.

Previously, a different ingredient of evening primrose oil (phenylalanine) has been considered the most important factor in its proposed effects on migraines. However, more recently a study on 129 participants over a 6 month period examined the benefits of polyunsaturated fatty acid consumption(22).

Of the 129 participants evaluated, 86% experienced a reduction in both headache frequency and length of the attack.

22% of those studied actually became free of migraines altogether. A group of 14% only, showed minimal or no improvement to the therapy.

evening primrose oil benefits


How to Take Evening Primrose Oil | Dosages

The literature describes variable dosages for each condition.


1-4 capsules (360mg linoleic acid/ 40-45mg GLA) twice per day for 12 weeks(23) OR

4-12 capsules (500mg evening primrose oil per capsule) in two daily divided dosages for up to 5 months(23) OR

Topical application of 20% evening primrose oil cream, twice daily for up to 4 months(23) OR

Normally 200-400mg of GLA or 2-4g of evening primrose oil daily.


Rheumatoid arthritis

540mg-600mg of evening primrose oil/ 20-30ml of evening primrose oil taken orally daily for 3-12 months(23)

As high as 2000-3000mg have been attempted clinically.


Weight loss

Normally 3-5g of evening primrose oil daily


Evening Primrose Oil | Side Effects & Safety

Evening primrose oil should always be consumed with food.

Special considerations should be made when taking evening primrose oil in the presence of the following conditions:



Previous knowledge from two papers in the 1980s suggested a risk of taking evening primrose oil when epileptic as it was thought to increase the rate of seizures, however, this has been disproven and it is suggested that formularies remove epilepsy as a precaution for evening primrose oil (24).


Bleeding disorders/Post surgical

Studies suggest an anti-coagulant effect of evening primrose oil consumption which puts consumers at risk of increased bleeding during surgery or in the presence of disease such as haemophilia(25).



The use of evening primrose oil during pregnancy is not supported in the literature and should be avoided(26).


Take Home Message

The truth about evening primrose oil as a supplement is that its high GLA content means it does have benefits as an anti-inflammatory and an anti-oxidant, which can help in the management of joint and skin issues. These effects explain the likely proposed benefits in other health areas. However, the evidence base remains lacking for the use of this aid for all people.

It seems that some people benefit more than others (perhaps due to genetic variability), and the only way you will know if evening primrose oil is the tool for you is to try it and see. It may indeed be the super supplement you’ve heard about.

Our articles should be used for informational and educational purposes only and are not intended to be taken as medical advice. If you’re concerned, consult a health professional before taking dietary supplements or introducing any major changes to your diet.

Reading Time: 6 minutes
  1. Mahady, G.B., Fong, H.H.S., Farnsworth, N.R., 2001. Botanical Dietary Supplements: Quality, Safety and Efficacy. Sweets and Zeitlinger, Lissie, The Netherlands, pp. 75–85.
  2. Rezapour-Firouzi, S., Arefhosseini, S.R., Ebrahimi-Mamaghani, M., Baradaran, B., Sadeghihokmabad, E., Mostafaei, S., Torbati, M. and Chehreh, M., 2015. Alteration of delta-6-desaturase (FADS2), secretory phospholipase-A2 (sPLA2) enzymes by Hot-nature diet with co-supplemented hemp seed, evening primrose oils intervention in multiple sclerosis patients. Complementary therapies in medicine, 23(5), pp.652-657.
  3. Albertazzi, P. and Coupland, K., 2002. Polyunsaturated fatty acids. Is there a role in postmenopausal osteoporosis prevention?. Maturitas, 42(1), pp.13-22.
  4. Belch, J.J.F., Shaw, B., O’Dowd, A., Curran, L., Forbes, C.D. and Sturrock, R.D., 1986. Evening primrose oil (efamol) as a treatment for cold-induced vasospasm (Raynauds Phenomenon). Progress in Lipid Research, 25, pp.335-340.
  5. Charnock, J.S., Crozier, G.L. and Woodhouse, J., 1994. Gamma-linolenic acid, black currant seed and evening primrose oil in the prevention of cardiac arrhythmia in aged rats. Nutrition research, 14(7), pp.1089-1099.
  6. Balasinska, B., 1998. Hypocholesterolemic effect of dietary evening primrose (Oenothera paradoxa) cake extract in rats. Food chemistry, 63(4), pp.453-459.
  7. Montserrat-de la Paz, S., Fernández-Arche, M.A., Bermúdez, B. and García-Giménez, M.D., 2015. The sterols isolated from evening primrose oil inhibit human colon adenocarcinoma cell proliferation and induce cell cycle arrest through upregulation of LXR. Journal of Functional Foods, 12, pp.64-69.
  8. Belch, J.J.F., Hill, A., 2000. Evening Primrose oil and borage oil in rheumatological conditions. Am. J. Clin. Nutr. 71, 352S–356S.
  9. Kleijnen, J., 1994. Evening Primrose oil. Br. Med. J. 309, 824–825
  10. Hudson, B.J.F., 1984. Evening Primrose (Oenothera ssp.) oil and seed. J. Am. Oil. Chem. Soc. 61, 540–543.
  11. Fan, Y.Y., Chapkin, R.S., 1998. Importance of dietary gamma-linolenic acid in human health and nutrition. J. Nutr. 128, 1411–1414.
  12. Siriwardhana, N., Kalupahana, N.S. and Moustaid-Moussa, N., 2012. Health benefits of n-3 polyunsaturated fatty acids: eicosapentaenoic acid and docosahexaenoic acid. Adv Food Nutr Res, 65, pp.211-222.
  13. El-Sayed, R.M., Moustafa, Y.M. and El-Azab, M.F., 2014. Evening primrose oil and celecoxib inhibited pathological angiogenesis, inflammation, and oxidative stress in adjuvant-induced arthritis: novel role of angiopoietin-1. Inflammopharmacology, 22(5), pp.305-317.
  14. Zurier, R.B., 1998. Gammalinolenic acid treatment of rheumatoid arthritis. In Medicinal fatty acids in inflammation (pp. 29-43). Birkhäuser Basel.
  15. Vasiljevic, D., Veselinovic, M., Jovanovic, M., Jeremic, N., Arsic, A., Vucic, V., Lucic-Tomic, A., Zivanovic, S., Djuric, D. and Jakovljevic, V., 2016. Evaluation of the effects of different supplementation on oxidative status in patients with rheumatoid arthritis. Clinical rheumatology, pp.1-7.
  16. Bamford, Joel (30 April 2013). “Oral evening primrose oil and borage oil for eczema”. Cochrane Database of Systematic Reviews 2013 (4): CD004416.
  17. Simon, D., Eng, P.A., Borelli, S., Kägi, R., Zimmermann, C., Zahner, C., Drewe, J., Hess, L., Ferrari, G., Lautenschlager, S. and Wüthrich, B., 2014. Gamma-linolenic acid levels correlate with clinical efficacy of evening primrose oil in patients with atopic dermatitis. Advances in therapy, 31(2), pp.180-188.
  18. Chung, B.Y., Kim, J.H., Cho, S.I., Ahn, I.S., Kim, H.O., Park, C.W. and Lee, C.H., 2013. Dose-dependent effects of evening primrose oil in children and adolescents with atopic dermatitis. Annals of dermatology, 25(3), pp.285-29
  19. Haslett C, Douglas JG, Chalmers SR, et al. A double-blind evaluation of evening primrose oil as an antiobesity agent. Int J Obes. 1983;7:549-553.
  20. Lieber, J., 1961. Management of Refractory Obesity. Br Med J, 2(5251), pp.587-587.
  21. Garcia CM, Carter J, Chou A. Gamma linolenic acid causes weight loss and lower blood pressure in overweight patients with family history of obesity. Swed J Biol Med.1986;4:8-11.
  22. Wagner, W. and Nootbaar-Wagner, U., 1997. Prophylactic treatment of migraine with gamma-linolenic and alpha-linolenic acids. Cephalalgia, 17(2), pp.127-130.
  23. Mayo Clinic. (2013). Drugs and Supplements: Evening primrose (Oenothera spp.) http://www.mayoclinic.org/drugs-supplements/evening-primrose/dosing/hrb-20059889
  24. Puri, B.K., 2007. The safety of evening primrose oil in epilepsy. Prostaglandins, Leukotrienes and Essential Fatty Acids, 77(2), pp.101-103.
  25. Riaz, A., Khan, R.A. and Ahmed, S.P., 2009. Assessment of anticoagulant effect of evening primrose oil. Pak J Pharm Sci, 22(4), pp.355-9.
  26. Bayles, B. and Usatine, R., 2009. Evening primrose oil. American family physician, 80(12), pp.1405-1408

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Liam Swithenbank

Liam Swithenbank

Writer and expert

Liam Swithenbank is our expert supplier quality assurance technologist. He holds a Bachelor of Science degree in Sport and Exercise Science and a Master of Science degree in Nutrition, and his expertise now lie in specialist ingredients for sports nutrition products.

Liam’s academic research has involved investigating the effects of sodium bicarbonate on power output in elite rugby players, and also the effects of beetroot juice on VO2 max on a cohort of well-trained runners. For his postgraduate thesis, Liam investigated the effects of protein intake on lean tissue mass.

Liam’s experience spans from working in compliance and labelling to developing new products, for a number of large companies in the UK. Liam is a big believer in balance, and believes moderation is key to sustain a healthy and active lifestyle.

Find out more about Liam’s experience here.

During his spare time Liam enjoys rock climbing, cycling and good food. Liam is a massive foodie and enjoys creating and developing new and exciting recipes in his home kitchen.

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