Evening primrose (GLA)
The seed oil people take for breast pain, the menopause and dry skin.
- Breast pain
- Hot flushes
- Itchy, dry skin
- Mood in menopause
- Starting labour
A plain-English overview, not advice. Written from published reviews and trials and from what people say in public forums.
Compare evening primrose (GLA) prices per dose
On this page
What is evening primrose (GLA)?
Evening primrose is a yellow-flowered plant, Oenothera biennis, and the oil pressed from its seeds is what fills the capsules. About seven-tenths of that oil is linoleic acid and roughly a tenth is gamma-linolenic acid, or GLA, which is the figure labels quote and the one this site compares on. It is bought mostly by women, and the research has followed: breast pain has drawn more study than anything else, then premenstrual symptoms, hot flushes, the skin and the end of pregnancy. It is one of the older names on a British shelf.
Why do people take evening primrose (GLA)?
Breast pain
The thinking. Breast pain that comes and goes with the monthly cycle is what evening primrose oil is best known for in Britain, and reviewers say it has drawn more study than any of its other uses. The thinking rests on GLA: the body turns it into DGLA, which feeds signalling molecules on the calming side of inflammation.
What research has found. A meta-analysis pooling thirteen trials and just over 1,750 women set the oil against dummy capsules and against the other things given for breast pain. It found no difference in how many women got relief, whichever comparison was made. A fair body of trials has looked at this, and most point the same way.
Hot flushes
The thinking. Hot flushes are what most women want something for at the menopause, and evening primrose oil is one of the plant options picked up by those who would rather not take hormones. The idea is the same fatty-acid one: GLA shifts the balance of signalling molecules the body builds from omega-6 fats.
What research has found. A review of six trials in 450 women found about two fewer flushes a day with the oil, too small a gap to be statistically sure of, and shorter flushes that were no less strong. A trial of 56 women saw the same split, with only severity easing enough to count. Studies here point in different directions, so this one is still being worked out; the dose, how long people took it and who took part all seem to matter.
Itchy, dry skin
The thinking. Dry, itchy skin and eczema are the other long-standing reason people take the capsules, and the idea is that the fats join the skin’s own barrier while GLA damps down the messengers behind an itch. The same oil is also sold as a cosmetic to rub in, which is a different thing from swallowing it.
What research has found. A Cochrane review pooled 27 studies and just under 1,600 people taking evening primrose or borage oil by mouth for eczema, and overall symptoms, rated by the people themselves and by their doctors, came out no better than on dummy capsules. A later trial in adults on a prescription acne medicine found their skin held more water with the oil, though oiliness was unchanged. A reasonable number of trials have measured this, and most of them agree.
Mood in menopause
The thinking. The menopause brings more than flushes, and how a woman feels in herself is often the part she minds most. Evening primrose oil tends to be taken for the whole bundle rather than for flushes alone, on the same reasoning about omega-6 fats and the signals the body builds from them.
What research has found. One trial gave 189 postmenopausal women a gram of the oil a day for eight weeks and scored them on a standard menopause questionnaire. The psychological part of that score fell further than it did on placebo. Few studies have measured this yet, so there is little to go on either way.
Starting labour
The thinking. At the very end of pregnancy some women take evening primrose oil hoping to get things moving. The thinking is that it has prostaglandin-like effects on the cervix and softens it before labour, and that it is cheap and involves no procedure. In the trials it was swallowed as capsules over the last week or so; other studies inserted it instead.
What research has found. A meta-analysis of six studies of the oil taken by mouth found no clear difference in how ready the cervix was, on the score clinicians use for it. A trial in 80 first-time mothers at 40 weeks found no difference either, in when they delivered or in how long the stages of labour ran. Research here is still young: a few studies so far, mostly pointing the same way.
What does evening primrose (GLA) do in the body?
Evening primrose oil is mostly two omega-6 fats: linoleic acid, around seven-tenths of it, and gamma-linolenic acid, GLA, around a tenth. Taking the oil raises the amount of GLA in the blood, and the body goes on to build a longer fat called DGLA from it.
DGLA is the one that matters. Enzymes turn it into series-1 prostaglandins and into a molecule called 15-HETrE, and both sit on the quieting side of the body’s inflammatory signalling; 15-HETrE also gets in the way of the enzyme that makes the more inflammatory messengers out of arachidonic acid. GLA itself damps down signals such as interleukin-1 beta, interleukin-6 and tumour necrosis factor alpha. How much DGLA a person makes varies, partly with the version of the FADS genes they carry, which reviewers think is one reason trials of GLA come out so differently.
What do people say about taking evening primrose (GLA)?
These are anecdotes people have shared, not evidence.
What people like
- All six threads come from one British parenting forum, so the balance of views may reflect that community as much as the oil.
- Premenstrual irritability and rage is much the commonest thing people say it eased, several describing themselves as noticeably calmer before a period.
- Several also describe feeling calmer in general rather than only around a period, and a couple say the same of anxiety at the menopause.
- Two people say their hot flushes eased, and one who stayed on it a year for cyclical breast pain says most of that pain went.
Common complaints
- One thread exists specifically to collect side effects, so the weight of bad reports in it is no measure of how common they are.
- In that thread the recurring complaint by far is mood: anxiety, tearfulness, low spirits and broken sleep, usually within days or weeks of starting.
- Stomach upset comes up across the threads, from nausea and bloating to one case of diarrhoea bad enough to stop, though most call it mild.
- Sore breasts and worse cramps are mentioned by a few, which is the opposite of what they were hoping for.
- Several people took it for months and noticed nothing whatever, and some of those moved on to a different seed oil instead.
How people take it
- Doses named run from 500 mg a day up to three grams, most commonly one or two 1,000 mg capsules daily.
- Some take it right through the cycle, others only in the week or two before a period, or only up to ovulation.
- Nobody describes a quick result: six weeks, three months and a year are the spans people give before judging it.
- It is usually taken alongside other supplements, such as B vitamins, magnesium, zinc or vitamin D, which makes single accounts hard to pin on it.
- Those who stopped because of mood or stomach effects mostly say things settled within days to a few weeks afterwards.
Read from these public discussions:
- Evening primrose oil for PMT (Mumsnet, 2011)
- Evening Primrose Oil when TTC - yay or nay? (Mumsnet, 2013)
- Evening Primrose Oil side effects - my story (Mumsnet, 2015)
- PMS rage - evening primrose oil (Mumsnet, 2019)
- To think evening primrose oil is Amazing! (Mumsnet, 2020)
- Finally some relief without HRT (Mumsnet, 2021)
What forms of evening primrose (GLA) are there?
| Form | What’s different | Per serving, on products we list |
|---|---|---|
| Evening primrose oil (GLA) | Oil pressed from evening primrose seeds; roughly a tenth of it is gamma-linolenic acid. | 215 mg |
What else is worth knowing about evening primrose (GLA)?
- The Cochrane eczema review cites a study finding the oil may increase bleeding in people taking warfarin, and a case report of a risk with continuous use beyond a year.
- Side effects in the trials were mild and mostly to do with the stomach, such as nausea and bloating; the breast-pain review found them no commoner with the oil than with dummy capsules.
- Labels usually quote the whole oil in a capsule, commonly 500 mg or 1,000 mg, and the GLA in it is about a tenth of that - and GLA is what our price tables compare.
- Reviewers say not to expect a quick answer and describe four to six months of steady use; the trials ran from one week to nine months.
If you take medication, are pregnant, or have a health condition, check with a pharmacist or GP first.
The research behind this page (14 studies)
- A Systematic Review and Meta-Analysis of the Efficacy of Evening Primrose Oil for Mastalgia Treatment. (2021, meta-analysis)
- The Effect of Evening Primrose Oil on Menopausal Symptoms Management: A Systematic Review and Meta-Analysis. (2025, systematic review)
- The effect of oral evening primrose oil on menopausal hot flashes: a randomized clinical trial. (2013, randomised trial)
- Oral evening primrose oil and borage oil for eczema. (2013, meta-analysis)
- Effect of Evening Primrose Oil Supplementation on Selected Parameters of Skin Condition in a Group of Patients Treated with Isotretinoin-A Randomized Double-Blind Trial. (2022, randomised trial)
- Impact of evening primrose oil consumption on psychological symptoms of postmenopausal women: a randomized double-blinded placebo-controlled clinical trial. (2020, randomised trial)
- The effect of evening primrose oil on labor induction and cervical ripening: A systematic review and meta-analysis. (2021, meta-analysis)
- Evening primrose oil and labour, is it effective? A randomised clinical trial. (2018, randomised trial)
- Gamma-linolenic acid, Dihommo-gamma linolenic, Eicosanoids and Inflammatory Processes. (2016, review)
- Evening Primrose ( Oenothera biennis ) Biological Activity Dependent on Chemical Composition. (2018, review)
- An updated review on efficacy and benefits of sweet almond, evening primrose and jojoba oils in skin care applications. (2022, review)
- Evening Primrose ( Oenothera biennis ) Oil in Management of Female Ailments. (2019, review)
- Evening primrose oil: a comprehensive review of its bioactives, extraction, analysis, oil quality, therapeutic merits, and safety. (2023, review)
- Evening primrose oil for cervical ripening in term pregnancies: a systematic review and meta-analysis. (2023, review)
How much does evening primrose (GLA) cost?
That depends on the form and the pack, so we work out the price of the same dose of every evening primrose (GLA) product we can find and rank them.