--- title: Evening primrose oil for PMDD: what the evidence says description: Evening primrose oil for PMDD has little solid evidence behind it: most controlled trials show no benefit over placebo, and it's usually mild. url: https://niyora.com/treatments/evening-primrose-oil-for-pmdd/ --- - [Niyora](https://niyora.com/) - [Treatments](https://niyora.com/treatments/) - Evening primrose oil for PMDD: does it work? Treatments # Evening primrose oil for PMDD: does it work? No trial has tested evening primrose oil in women with a confirmed PMDD diagnosis, only in PMS. The PMS evidence itself is mixed: several well-controlled trials found no benefit over placebo, while two more recent trials found it helped more than placebo did. Updated 14 October 2026 Niyora editorial Mixed evidence Strength of evidence Mixed Trials disagree, or the effect is small. - None - Limited - Mixed - Moderate - Strong ## At a glance - No trial has tested evening primrose oil specifically in people diagnosed with PMDD. - PMS trial results are mixed: the best-designed crossover trials found no benefit over placebo, but two recent Iranian trials found a real effect. - Trials used 1,000 mg twice daily, taken for at least two cycles, with reviewers recommending 4 to 6 months of regular use before judging it. - Side effects reported in trials were generally mild, mainly headache, nausea, or an upset stomach. - If you're pregnant, breastfeeding, trying to conceive, or on other medication, this hasn't been studied for you. ## Strength of evidence Mixed evidence - None - Limited - Mixed - Moderate - Strong No trial has studied EPO in people with a confirmed PMDD diagnosis. For PMS, well-controlled trials, a 1996 review of 7 trials and a 1990 crossover trial, found no benefit over placebo, while two 2018 to 2019 Iranian trials found EPO beat placebo by a wide margin. ## Does evening primrose oil work for PMDD? No trial has tested evening primrose oil (EPO) in women or girls with a confirmed PMDD diagnosis, the kind made with daily symptom ratings over at least two cycles. Every trial on EPO and premenstrual symptoms has studied PMS instead, a different and far more common pattern. For PMS, the evidence is mixed rather than clearly positive. The best-designed studies identified by a 1996 review of EPO trials for PMS [3], and a separate 1990 Australian crossover trial [4], found no real difference between EPO and placebo. Two more recent Iranian trials found the opposite, with EPO beating placebo by a wide margin [7] [8]. **The honest summary is that EPO has no PMDD-specific evidence, and the PMS evidence leans more often toward no benefit over placebo than toward a real effect.** What the research says Evidence grade: mixed. No trial has studied EPO in diagnosed PMDD. Well-controlled PMS trials mostly show no benefit over placebo, though two more recent trials found it helped. ## What does the research say? The clearest picture comes from comparing trial quality. A 1996 review [3] pooled every placebo-controlled EPO trial available at the time and found only two solid enough to trust; both showed no benefit for PMS. A 1990 Australian trial gave 38 women EPO and placebo across six cycles. Symptom scores fell in both groups, and the authors concluded the improvement was a placebo effect [4]. Two Iranian trials, run at the same university, found EPO did better than placebo. An 80-student trial in 2018 found scores drop from roughly 61 to 21 points with EPO, against a rise in the placebo group [8]. A 120-student trial in 2019 found EPO outperformed both placebo and vitamin B6 [7]. Neither trial used a DSM-5 PMDD diagnosis. A 2024 systematic review of EPO across inflammatory conditions, including PMS, concluded it hasn't demonstrated effectiveness there [1]. | Trial | Design | Result | | --- | --- | --- | | 1996 review [3] | Review of 7 placebo-controlled PMS trials | Two best-designed trials: no benefit over placebo | | 1990 Australian trial [4] | RCT, n=38, 6-cycle crossover | No difference from placebo; called a placebo effect | | 2018 Iranian trial [8] | RCT, n=80, 2 cycles | EPO reduced symptom severity more than placebo | | 2019 Iranian trial [7] | RCT, n=120, 2 cycles | EPO reduced symptom severity more than placebo and vitamin B6 | Right now Right now, before you decide anything - 1 Leave the room if you're mid-argument. Say you'll come back in 20 minutes. - 2 Breathe out for six counts, longer than your in-breath, for a minute or two. - 3 Write down exactly what happened, in your own words, before you reply. - 4 Wait before sending a message or making a decision you can't take back. Niyora walks you through this when it happens: - Calm down - - See it another way - - Choose what to say ## How long does it take to work? Trials on EPO for premenstrual symptoms measured results after two to six menstrual cycles, not after a few days. A review of EPO research for women's health conditions says not to expect an immediate response, and recommends regular use for 4 to 6 months before judging the effect [6]. In the trials, doses ranged from 1,000 mg taken twice daily (2,000 mg total) for PMS [7] [8], up to 3,000 mg daily for cyclical breast pain, measured over six months [5]. The 1990 Australian trial found some symptom improvement appeared within the first cycle, but it didn't separate from the placebo effect over six cycles of use [4]. If you're trying EPO, give it a full cycle or two before deciding, and track your symptoms daily so you can see a real pattern rather than guessing from memory. Our [guide to how long evening primrose oil takes to work](https://niyora.com/treatments/how-long-does-evening-primrose-oil-take-to-work/) and [dosage page](https://niyora.com/treatments/evening-primrose-oil-dosage/) go through the specifics. ## What are the side effects? Evening primrose oil was generally well tolerated across the trials reviewed here. The 2018 Iranian trial specifically noted few side effects in the EPO group [8], and a 2024 systematic review across several conditions didn't flag major safety concerns, even though it didn't find a PMS benefit [1]. Reported side effects in EPO research, across conditions, are typically mild: - Headache - Nausea or an upset stomach - Soft stools These tend to ease when you take EPO with food. None of the trials covered here reported serious adverse effects, though the trials were small and side effects weren't always tracked in detail. Our [evening primrose oil side effects page](https://niyora.com/treatments/evening-primrose-oil-side-effects/) covers what's been reported in more depth, including effects on mood. ## Who should avoid it? If you're pregnant, breastfeeding, or trying to conceive, evening primrose oil hasn't been well studied for you outside of late pregnancy. A 2018 trial gave EPO to women at 40 weeks of pregnancy to see if it affected labor, and found no difference in labor length, delivery outcomes, or newborn health compared with placebo [2]. That trial was done under medical supervision, close to delivery; EPO hasn't been studied the same way earlier in pregnancy. These situations call for extra caution too: - Take other medication regularly - Have a bleeding disorder or are due for surgery - Have reacted to evening primrose oil or similar supplements before A doctor can weigh EPO against what you're already taking and decide if it fits. When to see a doctor If your symptoms take a week of every month, or you have thoughts of hurting yourself, see a GP or gynecologist and bring two months of daily notes, whether or not you're also trying EPO. ## What else helps alongside it? Evening primrose oil isn't a first-line treatment for PMDD. Guidelines point to options with stronger evidence instead: SSRIs, which some people take only in the two weeks before their period, certain hormonal contraceptives, and cognitive behavioral therapy (CBT). A doctor decides which combination fits your history and symptoms. If you're not sure whether what you're feeling fits PMS or PMDD, [our guide to PMDD](https://niyora.com/pmdd/) walks through how the diagnosis is made and what's different about it. For a fuller rundown of what actually has evidence behind it, see [PMDD treatment: what actually helps](https://niyora.com/treatments/pmdd-treatment/) and [PMS supplements: what actually helps](https://niyora.com/techniques/supplements/). Daily tracking matters here. Whatever you try, note your mood and physical symptoms every day for at least two cycles so you, and your doctor, can see if a real pattern shows up, rather than guessing from a single week before your period. ## What helps in the moment? Evening primrose oil, if it works at all, works slowly over months. It won't help with a hard moment happening right now. For that, you need something faster. - Leave the room if you're mid-argument, and say you'll come back in 20 minutes. - Breathe out for six counts, longer than you breathe in, for a minute or two. - Write down exactly what happened, in your own words, before you respond to anyone. - Wait before you send a message or make a decision you can't take back. If you want somewhere to put the fight before you answer, Niyora is a PMS and PMDD support app. Its Moon feature lets you write down what happened, see it from another side, and draft a reply you can hold onto for 20 minutes before you decide whether to send it. From the research library ## Research on evening primrose oil 38 studies in the library look at evening primrose oil in PMS and PMDD. They were published from 1983 to 2026, and each one has a short summary of what was tested and found. 38 studies, 1983 to 2026 How strong the studies are Strong study design 4 Moderate study design 18 Early or limited evidence 16 - [Systematic review, 2009Which herbs, vitamins and minerals help treat PMS?Only calcium has good evidence to work for PMS. Chasteberry and vitamin B6 may help, but most of the 62 products people try lack proper research.Strong study design](https://niyora.com/research/papers/herbs-vitamins-and-minerals-in-the-treatment-of-premenstrual-syndrome-a-2009/) - [Systematic review, 2007What treatments work for premenstrual syndrome?Many treatments have been studied for PMS, but researchers face a major challenge: there is no standard way to measure symptom severity, making it difficult to know which treatments truly work.Strong study design](https://niyora.com/research/papers/premenstrual-syndrome-2007/) - [Study, 2002Which PMS treatments have good scientific evidence?Calcium at 1200 mg daily and certain antidepressants have good evidence of working. Many popular treatments like vitamin B6, evening primrose oil, and birth control pills lack strong evidence. Some treatments like progesterone do not work.Strong study design](https://niyora.com/research/papers/premenstrual-syndrome-evidence-based-treatment-in-family-practice-2002/) - [Randomised trial, 2000Which dietary supplements help PMS?Only calcium has strong evidence from large rigorous trials. Magnesium, vitamin E, and carbohydrate supplements show limited promise but need more research. Vitamin B6 and evening primrose oil have mixed results.Strong study design](https://niyora.com/research/papers/the-potential-for-dietary-supplements-to-reduce-premenstrual-syndrome-pms-2000/) - [Study, 2024Does a combination of evening primrose oil, tocotrienol, and vitamin B6 reduce premenstrual symptoms?Yes. In women with PMS taking this combination for 3 months, premenstrual symptoms improved significantly. The overall PMS score dropped by 61.03%, menstrual pain dropped by 75.20%, and breast tenderness dropped by 82.54%.Moderate study design](https://niyora.com/research/papers/a-real-world-study-to-evaluate-the-effectiveness-of-evening-primrose-oil-in-2024/) - [Randomised trial, 2024Does a herbal soft gel capsule with three oils reduce PMS symptoms?The capsule reduced women's PMS symptoms when compared to their baseline, but was not significantly better than taking sunflower oil.Moderate study design](https://niyora.com/research/papers/effects-of-the-herbal-soft-gel-capsule-containing-pimpinella-anisum-oenothera-2024/) [See all 38 studies on evening primrose oil](https://niyora.com/research/topics/treatment-evening-primrose/) ## Questions people ask Does evening primrose oil help PMDD rage? + No trial has tested evening primrose oil in women with diagnosed PMDD, so there's no evidence it eases PMDD rage specifically. The PMS trials that exist are mixed, with several well-designed studies showing no difference from placebo, and two more recent trials finding it helped. How much evening primrose oil should I take for PMDD? + Trials studying premenstrual symptoms used 1,000 mg of evening primrose oil twice daily, or 3,000 mg total for breast pain. There's no dose established for PMDD specifically, since no trial has studied it in people with that diagnosis. A doctor can advise on the right amount for you. How long until evening primrose oil works? + A review of evening primrose oil research says not to expect an immediate response, and recommends regular use for 4 to 6 months before judging the effect. Trials on premenstrual symptoms measured results after two to six menstrual cycles, not after a few days. Is evening primrose oil safe to take every day? + Evening primrose oil was generally well tolerated in the trials reviewed here, with few side effects reported, mainly headache, nausea, or an upset stomach. If you're pregnant, breastfeeding, trying to conceive, or taking other medication, this hasn't been well studied for your situation specifically. What should I do if evening primrose oil isn't helping? + If evening primrose oil hasn't helped after a few months, options with stronger evidence for PMDD exist. These include SSRIs taken only in the luteal phase, certain hormonal contraceptives, and cognitive behavioral therapy, decided based on your symptoms and history. ## Sources - 1. [The effect of Oenothera biennis (Evening primrose) oil on inflammatory diseases: a systematic review of clinical trials](https://doi.org/10.1186/s12906-024-04378-5), BMC complementary medicine and therapies, 2024 - 2. [Evening primrose oil and labour, is it effective? A randomised clinical trial](https://doi.org/10.1080/01443615.2017.1386165), Journal of obstetrics and gynaecology : the journal of the Institute of Obstetrics and Gynaecology, 2018 - 3. [Is evening primrose oil of value in the treatment of premenstrual syndrome?](https://doi.org/10.1016/0197-2456(95)00082-8), Controlled clinical trials, 1996 - 4. [Evening primrose oil and treatment of premenstrual syndrome](https://doi.org/10.5694/j.1326-5377.1990.tb136857.x), The Medical journal of Australia, 1990 - 5. [Vitamin E and evening primrose oil for management of cyclical mastalgia: a randomized pilot study](https://pubmed.ncbi.nlm.nih.gov/20359269/), Alternative medicine review : a journal of clinical therapeutic, 2010 - 6. [Evening Primrose ( Oenothera biennis ) Oil in Management of Female Ailments](https://doi.org/10.6118/jmm.18190), Journal of menopausal medicine, 2019 - 7. [The Effect of Evening Primrose and vitamin B6 on premenstrual syndrome: a randomized clinical trial](https://doi.org/10.22038/ijogi.2019.12660), DOAJ (DOAJ: Directory of Open Access Journals), 2019 - 8. [Effect Of Evening Primrose On Premenstrual Syndrome: A Randomized Clinical Trial](https://doi.org/10.5281/zenodo.1157976), Zenodo (CERN European Organization for Nuclear Research), 2018 Ask AI about this page Copy prompt ChatGPT ↗ Claude ↗ Perplexity ↗ Google AI Mode ↗ Grok ↗ On this page - [Does evening primrose oil work for PMDD?](#does-evening-primrose-oil-work-for-pmdd) - [What does the research say?](#what-does-the-research-say) - [How long does it take to work?](#how-long-does-it-take-to-work) - [What are the side effects?](#what-are-the-side-effects) - [Who should avoid it?](#who-should-avoid-it) - [What else helps alongside it?](#what-else-helps-alongside-it) - [What helps in the moment?](#what-helps-in-the-moment) - [Research](#research) - [Questions](#faq) Niyora PMS & PMDD support For the hard moment before your period. Private, no account. [Get it on iPhone](https://apps.apple.com/app/niyora-pms-emotions/id6764561688) ## Keep reading Treatment Evening primrose oil: what it is and whether it helps PMS Treatment Evening primrose oil for PMS: does it work? Treatment Evening primrose oil side effects, including mood Treatment Evening primrose oil 1000 mg: dosage, timing, and benefits Treatment How long until evening primrose oil works, and what are the signs? Treatment Evening primrose oil for mood swings: what the trials found Treatment Evening primrose oil for perimenopause mood: does it work? Treatment PMDD treatment: what actually helps Condition PMDD (premenstrual dysphoric disorder), explained