evening primrose flower

Evening primrose oil: benefits, dosage & side-effects

Find out all about evening primrose oil, including what it does, the benefits to taking it and how much you might need

Written by Cheryl Freedman on December 11, 2018 Reviewed by Dr Sarah Schenker on December 18, 2018


What is evening primrose oil and what does it do?

Evening primrose oil is the oil extracted from the seeds of the yellow evening primrose wildflower, Oenothera biennis. It is a rich source of linoleic acid and gamma-linoleic acid (GLA), both omega-6 essential fatty acids.1,2 GLA is used to make hormone-like substances called prostaglandins, which can help calm inflammation.3 Many women use evening primrose oil (EPO) to manage symptoms of pre-menstrual syndrome (PMS) and menopause, such as hot flushes.4 EPO is also used to help ease skin conditions including eczema and acne.5 Evening primrose oil is most often taken as capsules but sometimes comes as a liquid.

Benefits of evening primrose oil

What does evening primrose do in the body?

Indigenous Americans would use the leaves and bark of the evening primrose plant for stomach and liver complaints.6 EPO is also used as a traditional herbal remedy to relieve the itching that’s associated with dry skin conditions.7

The evidence for taking EPO is still inconclusive, but some studies show it may be helpful for:

  • menopause symptoms – there’s a lot of anecdotal evidence from menopausal women that using evening primrose oil can ease hot flushes. One 2013 study found taking EPO for six weeks could relieve the frequency, intensity and length of hot flushes. The women in the study also reported a significant improvement in their sense of wellbeing.8

  • pre-menstrual syndrome (PMS) – many women take EPO for PMS symptoms such as water retention, breast tenderness and low mood; the Royal College of Obstetricians and Gynaecologists reports that it can ease breast tenderness9. A 1983 study concluded that taking EPO was 'highly effective' for treating symptoms of PMS,10 but more recent research is needed.

  • dry skin conditions – the European Medicines Agency says EPO can be used for relief of itching in short-term and long-term dry skin conditions,11 and is often taken by people with eczema to help prevent dry, itchy skin.12 But a 2013 Cochrane Review concluded evening primrose oil is no more effective than a placebo in treating eczema.13

  • acne – it’s thought the GLA in evening primrose oil may improve acne, by reducing inflammation and minimising scarring; one 2014 Korean study found that GLA reduced inflammation in acne sufferers.14 But more evidence is needed before EPO can be recommended as an acne treatment.

  • arthritis – EPO is often used by those with rheumatoid arthritis to ease pain and stiffness. One study found taking it helped ease morning stiffness in patients with the condition.15 Versus Arthritis says, while the evidence isn't conclusive, it may ‘help in the regulation of pain and inflammation'.16

If you’re interested in taking evening primrose oil, talk to your GP or a healthcare professional first.


How much evening primrose oil is safe to take?

There is no official upper limit for EPO, but the European Medicines Agency warns that children under 12 should not take it.17 You should also avoid taking EPO if you:18
  • are on blood thinning drugs like warfarin, as EPO has blood-thinning effects
  • are due to have surgery in two weeks
  • have epilepsy, schizophrenia or any other seizure disorder, as there's a risk evening primrose oil may increase risk of seizure
  • are pregnant, as EPO can cause complications

Always check with your healthcare professional before taking evening primrose oil and read the label, as dose instructions may vary between products.


What are the side-effects of taking evening primrose oil?

Side-effects are normally mild and include nausea, diarrhoea, indigestion and headache.19 Very rarely, EPO can cause an allergic reaction. If you notice a rash, itching or breathing difficulties after taking it, seek medical attention immediately.20 Shop EPO Advice is for information only and should not replace medical care. Please check with your GP before trying any remedies.


1. ScienceDirect. Primrose oil 2. Marcus MacGill. Medical News Today. What are the uses of primrose oil? 3. Ricciotti E, FitzGerald GA. Prostaglandins and inflammation 4. Dr Deborah Rose Wilson. Healthline. 10 Benefits of Evening Primrose Oil and How To Use It

5. As above

6. Encyclopedia.com. Evening primrose oil 7. European Medicines Agency. Evening primrose oil 8. Farzaneh F, et al. The effect of oral evening primrose oil on menopausal hot flashes: a randomized clinical trial 9. Royal College of Obstetricians and Gynaecologists. Managing premenstrual syndrome 10. Horrobin DF. The role of essential fatty acids and prostaglandins in the premenstrual syndrome

11. As Source 7
12. As Source 4

13. Cochrane. Oral evening primrose oil and borage oil for eczema 14. Jung YJ, et al. Effect of dietary supplementation with omega-3 fatty acid and gamma-linolenic acid on acne vulgaris: a randomised, double-blind, controlled trial 15. Brzeski M, Madhok R, Capell HA. Evening primrose oil in patients with rheumatoid arthritis and side-effects of non-steroidal anti-inflammatory drugs 16. Versus Arthritis. Complementary and alternative medicines for the treatment of rheumatoid arthritis

17. As Source 7

18. Mayo Clinic. Evening primrose

19. As Source 7

20. As Source 4
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