Evening Primrose Oil
Evening primrose oil is a source of GLA studied for skin and women's health outcomes. Effects are often modest.
Overview
What is evening primrose oil?
Evening primrose is a plant native to North America that is rich in omega-6 fatty acids.
Evening primrose oil contain high concentrations of the polyunsaturated fatty acids, linoleic acid (70-78%) and gamma-linolenic acid (8-10%).
The most reliable benefits of evening primrose oil are for cervical ripening and dry eye disease. Despite its popularity, there is limited scientific evidence that evening primrose oil is beneficial for menopause, arthritis or many other conditions.
Dosage
A standard dose of evening primrose oil is 0.5 to 6 grams per day.
For cervical ripening, the typical oral dose used in studies is 6 grams per day.
For acne, the typical oral dose is around 2 grams per day.
Optimal dosages have not been established.
Effect graph
Effect heatmap
SupplementDEX Database
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Database Snapshot
Most evening primrose oil research is concentrated in a handful of conditions.
- Eczema accounts for 15 of 51 studies (29%).
- Cyclical Mastalgia (Breast Pain) accounts for 13 of 51 studies (25%).
- Menopause accounts for 9 of 51 studies (18%).
- Sparse coverage remains for Dry eye disease, Acne.
Dietary Sources
Top dietary sources
Ranked by amount per 100 g
Evening primrose oil is a rich source of gamma-linolenic acid.
- 1.34 g100 g
- 0.081 g100 g
Other sources include Black Currant Seed Oil, Borage Seed Oil, Breast Milk, Green Leafy Vegetables, Nuts, and Spirulina.
Safety
Evening primrose oil is generally well tolerated when used at the standard dosages.
Dose windows
Long-term
Oral doses of 2 g/day have been safely used for up to 12 months. [10713]
Side effects
- Bloating
- Diarrhea
- Dyspepsia
- Flatulence
- Headache
- Nausea
- Soft stools
- Stomach pain
- Vomiting
Special populations
Pregnancy & breastfeeding
Likely safeIn pregnant women, evening primrose oil is possibly safe when used at doses of up to 4 grams per day (orally) for up to 10 weeks, but may increase the likelihood of side effects at higher doses. Evening primrose oil has been linked to a single case of diffuse ecchymoses and petechiae located on the trunk, extremities and face of a newborn female whose mother self-medicated with raspberry leaf tea and a total of 13 x 500 mg capsules (total dose 6.5 grams) of evening primrose oil, vaginally and orally, in the week prior to delivery. In lactating women, evening primrose oil is possibly safe at a dose of 2 g twice per day (320 mg GLA + 2800 mg linoleic acid per day) for up to 8 months. Supplementation for 8 months (Efamol) may increase levels of fatty acids and alter the composition of breast milk. Gamma-linolenic is naturally present in breast milk in high quantities. Supplementation of nursing mothers with evening primrose oil increases breast milk concentrations of linoleic acid and GLA but is not associated with any adverse reactions in breastfed infants. Evening primrose oil supplementation was started at an average of 3.4 months postpartum.
Children
Likely safeOral doses of up to 6 g/day have been safely used for up to 4 months in children above 12 years of age. [10714] In children, oral evening primrose oil supplementation is possibly safe when used at a dose of up to 3 grams per day for up to 5 months. In children aged 15 years or younger, oral evening primrose oil (Efamol, 500 mg oil, 9% gamma-linolenic acid & 72% linoleic acid) at a dose of 2 or 4 grams per day has been used for up to 3 months. In children aged 2-10 years, topical evening primrose oil is possibly safe when applied twice daily for 3 months.
Other notes
Oral doses of up to 3 g/day have been safely used in hyperlipidemic patients for up to 4 months. Studies typically use a dose of 1 to 4 grams per day. Plasma levels of GLA peak at 2.6 to 4.4 hours after oral EPO supplementation.
Frequently Asked Questions
Takeaway
Evening primrose is a plant that contains the omega-6 fatty acids linolenic acid and gamma-linolenic acid. Evening primrose oil is extracted from the seeds of the plant and exerts an anti-inflammatory effect in the body by contributing to the production of 1-series prostaglandins.
Despite many people using evening primrose oil for conditions including asthma, menopause, acne and other conditions, there is limited scientific evidence for its benefits in high-quality human studies.
References
Sources50 references
SupplementDEX uses only high-quality sources to determine supplement effectiveness.
SupplementDEX Database · Cervical ripening
8 references1.SupplementDEX Database: Cervical ripening — The Use of Evening Primrose Oil for Cervical Ripening in Low-Risk Women with Term Pregnancy: A Randomized Double-Blinded Controlled Trial2024
In 48 low-risk term pregnancies per group, daily 1,000 mg vaginal evening primrose oil significantly raised post-intervention Bishop score (5.83 vs 5.19) versus placebo, without significant differences in cesarean rates.
2.SupplementDEX Database: Cervical ripening — Comparative Study of the Effect of Vaginal use of Primrose Oil with Misoprostol on Cervical Preparation of Prim Gravid Women: A Double-blind Clinical Trial2023
In 110 primigravid women at ≥40 weeks, vaginal evening primrose oil 1,000 mg versus 25 µg misoprostol significantly increased post-intervention Bishop score and differed on cervical ripening and labor induction outcomes.
3.SupplementDEX Database: Cervical ripening — The effect of evening primrose oil on cervical ripening and birth outcomes: A systematic review and meta-analysis2023
A meta-analysis of 5 high-heterogeneity studies including 652 participants found that evening primrose oil was effective for cervical ripening. Both oral and vaginal use of evening primrose oil significantly increased Bishop score relative to placebo. [10709]
4.SupplementDEX Database: Cervical ripening — Evening primrose oil for cervical ripening in term pregnancies: a systematic review and meta-analysis2021
A meta-analysis of 9 high-heterogeneity studies found that evening primrose oil was effective for cervical ripening, shortening the duration of labor and reducing the risk of cesarean section compared to placebo. [10710]
5.SupplementDEX Database: Cervical ripening — The effect of evening primrose oil on labor induction and cervical ripening: A systematic review and meta-analysis2021
A meta-analysis of 4 trials found no significant difference in Bishop score change with evening primrose oil versus control for cervical ripening (SMD 0.27, 95% CI crossing null) despite high heterogeneity (I² 91.4%).
6.SupplementDEX Database: Cervical ripening — Evening primrose oil and labour, is it effective? A randomised clinical trial2018
In 80 nulliparous women at 40 weeks (Bishop score <4), 1,000 mg evening primrose oil twice daily for 7 days did not change gestational age at delivery, labor duration, induction needs, or neonatal outcomes versus placebo.
8.SupplementDEX Database: Cervical ripening — Oral evening primrose oil: its effect on length of pregnancy and selected intrapartum outcomes in low-risk nulliparous women1999
In 54 nulliparous women taking oral evening primrose oil from 37 weeks versus 54 controls, gestation length and overall labor duration were unchanged; EPO use was associated with more prolonged rupture of membranes and assisted deliveries.
7.The effect of oral evening primrose oil on bishop score and cervical length amongst term gravidas. See external sourceExternal source
SupplementDEX Database · Dry eye disease
2 references9.SupplementDEX Database: Dry eye disease — Oral omega-6 essential fatty acid treatment in contact lens associated dry eye2008
A 6-month study including 76 female subjects with contact lens associated dry eye found that evening primrose oil (3 g/day Equazen) improved dryness after 3 and 6 months, and improved lens comfort after 6 months compared to placebo. After 6 months, there was an increase in tear meniscus height but no changes in Meibomian gland function (lipid layer thickness and quality) and ocular surface parameters (hyperaemia and staining). [10705]
10.SupplementDEX Database: Dry eye disease — Systemic linoleic and gamma-linolenic acid therapy in dry eye syndrome with an inflammatory component2003
A 45-day study of 26 patients with aqueous-deficient keratoconjunctivitis sicca (dry eye) found that a twice daily combination of linoleic acid (28.5 mg) and gamma-linolenic acid (15 mg) taken for 45 days reduced ocular surface inflammation and improved dry eye symptoms compared to placebo. [10706]
11.SupplementDEX Database: Cyclical Mastalgia (Breast Pain) — Effectiveness of Evening Primrose and Vitamin E for Cyclical Mastalgia: A Prospective Study2024
A 6-month study including 126 women with premenstrual breast pain given evening primrose oil (1000 mg twice daily), vitamin E (400 mg once daily) or their combination found that the combination group experienced the greatest reduction in breast pain severity compared to placebo. [10707]
12.SupplementDEX Database: Cyclical Mastalgia (Breast Pain) — A Systematic Review and Meta-Analysis of the Efficacy of Evening Primrose Oil for Mastalgia Treatment2021
A meta-analysis of 13 studies including 1752 participants with mastalgia found that evening primrose oil (1-4 g/day for 3-12 months) was similarly effective to topical NSAIDS, danazol, vitamin E and placebo. Evening primrose oil did not increase the likelihood of adverse events including nausea, headache, weight gain and altered taste. [10708]
13.SupplementDEX Database: Cyclical Mastalgia (Breast Pain) — Clinical Factors Affecting the Therapeutic Efficacy of Evening Primrose Oil on Mastalgia2020
In 1,015 mastalgia patients, evening primrose oil 2,600 mg/day relieved pain more than paracetamol 1,000 mg/day; hormone replacement therapy, levonorgestrel IUD use, and iron deficiency affected EPO responsiveness.
14.SupplementDEX Database: Cyclical Mastalgia (Breast Pain) — Compare the effect of flaxseed, evening primrose oil and Vitamin E on duration of periodic breast pain2017
In 90 women with cyclical breast pain over two menstrual cycles, daily flaxseed powder, evening primrose oil 2,000 mg, or vitamin E 400 IU all reduced pain duration compared with baseline, with group differences assessed at cycle end.
16.SupplementDEX Database: Cyclical Mastalgia (Breast Pain) — Mastalgia cured! Randomized trial comparing centchroman to evening primrose oil2012
A randomized trial compared centchroman with evening primrose oil for mastalgia treatment, assessing relative efficacy of the two agents for cyclical breast pain relief.
17.SupplementDEX Database: Cyclical Mastalgia (Breast Pain) — Vitamin E and evening primrose oil for management of cyclical mastalgia: a randomized pilot study2010
In 85 women with cyclical mastalgia over 6 months, intent-to-treat analysis showed EPO 3,000 mg/day, vitamin E 1,200 IU/day, or combined therapy improved worst-pain scores versus baseline, but group comparisons with placebo were nonsignificant.
19.SupplementDEX Database: Cyclical Mastalgia (Breast Pain) — A randomized multicenter study of gamolenic acid (Efamast) with and without antioxidant vitamins and minerals in the management of mastalgia2005
In 555 women with moderate-to-severe mastalgia over 4 blinded cycles, gamolenic acid (Efamast) with or without antioxidants did not reduce breast pain more than placebo fatty acids (40% response in placebo groups).
20.SupplementDEX Database: Cyclical Mastalgia (Breast Pain) — Evening primrose oil and fish oil for severe chronic mastalgia: a randomized, double-blind, controlled trial2002
In 120 women with severe chronic mastalgia over 6 months, evening primrose oil and fish oil each reduced painful days by ~12–16% with no significant benefit over respective control oils (P=0.73 and P=0.28).
21.SupplementDEX Database: Cyclical Mastalgia (Breast Pain) — Management of cyclical mastalgia in oriental women: pioneer experience of using gamolenic acid (Efamast) in Asia1999
In 66 Asian women with cyclical mastalgia, gamolenic acid (Efamast) from evening primrose oil yielded a 97% useful response at 6 months with minor side effects in 12%, supporting first-line use in this population.
22.SupplementDEX Database: Cyclical Mastalgia (Breast Pain) — Mastalgia: a 3 year Australian study1994
In 170 Australian mastalgia clinic patients over 3 years (mean age 42), evening primrose oil produced only 26% response versus 18% for vitamin B6, while low-dose danazol achieved 67% complete response.
23.SupplementDEX Database: Cyclical Mastalgia (Breast Pain) — Premenstrual syndrome and premenstrual breast pain (cyclical mastalgia): disorders of essential fatty acid (EFA) metabolism1989
A study proposed that premenstrual syndrome and cyclical mastalgia may reflect disorders of essential fatty acid metabolism, examining biochemical links between EFA abnormalities and these conditions.
15.The comparison of evening primrose oil, fructus agni casti and reassurance in the treatment of mastalgia. See external sourceExternal source
18.DANAZOL VERSUS OIL OF EVENING PRIMROSE IN THE TREATMENT OF MASTALGIA. See external sourceExternal source
SupplementDEX Database · Asthma
3 references24.SupplementDEX Database: Asthma — Epogam evening primrose oil treatment in atopic dermatitis and asthma1996
A 16-wk study including 22 children with asthma and atopic dermatitis taking topical skin steroids found that evening primrose oil (4-6 grams per day Epogam) had no effect on asthma symptoms compared to placebo. [10714]
25.SupplementDEX Database: Asthma — A study of evening primrose seed oil in atopic asthma1989
In atopic asthmatics given evening primrose oil (Efamol) for 8 weeks in a double-blind placebo trial, asthma control and histamine challenge tests did not improve despite changes in fatty acid profiles.
26.SupplementDEX Database: Asthma — Evening primose oil and fish oil are ineffective as supplementary treatment of bronchial asthma1989
In 29 asthmatics in a crossover trial, 15–20 mL/day evening primrose or fish oil for 10 weeks did not improve peak flow, symptoms, or medication use compared with olive oil placebo.
SupplementDEX Database · Eczema
14 references27.SupplementDEX Database: Eczema — Herbal Medicine in Children and Adults With Atopic Dermatitis: A Systematic Review and Meta-Analysis2024
A systematic review and meta-analysis of 51 RCTs (3,763 participants) evaluated herbal medicines for atopic dermatitis; included trials assessed multiple herbs and complex remedies for pruritus and disease severity.
28.SupplementDEX Database: Eczema — Oral evening primrose oil and borage oil for eczema2013
A Cochrane review of 27 EPO/BO eczema trials (1,596 participants) found oral borage and evening primrose oils did not significantly improve global eczema severity versus placebo (MD −2.22 on 0–100 scale, 95% CI −10.48 to 6.04).
29.SupplementDEX Database: Eczema — Evening primrose oil is effective in atopic dermatitis: a randomized placebo-controlled trial2008
In 25 atopic dermatitis outpatients per group over 5 months, 500 mg evening primrose oil twice daily improved clinical severity scores (extent, intensity, itching, dryness) versus sunflower oil placebo.
30.SupplementDEX Database: Eczema — 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 levels2002
In 14 atopic dermatitis patients with dry scaly lesions, evening primrose oil markedly reduced lesion extent and pruritus, raised serum IFN-gamma, and lowered IgE, suggesting benefit in noninflammatory atopic dermatitis.
31.SupplementDEX Database: Eczema — Evening primrose oil (Epogam) in the treatment of chronic hand dermatitis: disappointing therapeutic results1996
In 39 patients with chronic hand dermatitis over 16 weeks, Epogam evening primrose oil 600 mg/day GLA did not produce meaningful clinical or epidermal lipid improvements versus placebo in a double-blind trial.
32.SupplementDEX Database: Eczema — Placebo-controlled trial of essential fatty acid supplementation in atopic dermatitis1993
In 123 atopic dermatitis patients randomized to evening primrose oil, EPO plus fish oil, or placebo for 16 weeks, essential fatty acid supplementation did not improve clinical severity, steroid use, or symptom scores.
33.SupplementDEX Database: Eczema — Evening primrose oil (Efamol) in the treatment of children with atopic eczema1988
In 24 children with atopic eczema, higher-dose Efamol evening primrose oil for 4 weeks significantly improved eczema versus olive oil placebo (p<0.01) with corresponding plasma fatty acid changes.
34.SupplementDEX Database: Eczema — A long-term study on the use of evening primrose oil (Efamol) in atopic children1988
In atopic children given evening primrose oil long-term, clinical condition improved markedly after 4 weeks and remained improved through 20 weeks of supplementation, with changes in plasma and cell fatty acids.
35.SupplementDEX Database: Eczema — Evening primrose oil in the treatment of atopic eczema: effect on clinical status, plasma phospholipid fatty acids and circulating blood prostaglandins1987
In a 12-week double-blind trial (14 EPO, 11 placebo), evening primrose oil significantly improved eczema severity, inflammation, body surface involvement, dryness, and itch more than placebo.
36.SupplementDEX Database: Eczema — Efamol in the treatment of atopic dermatitis1987
A controlled clinical trial assessed Efamol evening primrose oil for atopic dermatitis symptom relief, evaluating whether gamma-linolenic acid supplementation improves disease activity.
37.SupplementDEX Database: Eczema — Atopic dermatitis and essential fatty acids: a biochemical basis for atopy?1985
In 99 atopic dermatitis patients in a crossover trial, evening primrose oil improved dermatitis; plasma EFA changes and a proposed delta-6-desaturase defect were noted, with effects likely not primarily immunological.
38.SupplementDEX Database: Eczema — Atopic eczema unresponsive to evening primrose oil (linoleic and gamma-linolenic acids)1985
In 123 atopic eczema patients in a crossover trial, oral evening primrose oil (2–8 g/day by age) did not significantly change erythema, scale, excoriation, lichenification, or overall severity.
39.SupplementDEX Database: Eczema — Oral evening-primrose-seed oil improves atopic eczema1982
An early randomized trial reported that oral evening primrose seed oil improved atopic eczema symptoms compared with control, supporting therapeutic benefit from gamma-linolenic acid supplementation.
40.SupplementDEX Database: Eczema — Treatment of atopic eczema with evening primrose oil1981
An early randomized trial evaluated evening primrose oil for atopic eczema, assessing whether oral supplementation improves dermatitis symptoms compared with control.
SupplementDEX Database · Acne
1 reference41.SupplementDEX Database: Acne — Effect of Evening Primrose Oil Supplementation on Biochemical Parameters and Nutrition of Patients Treated with Isotretinoin for Acne Vulgaris: A Randomized Double-Blind Trial2022
A 9-month study of 50 young adults (average age 22.5 years old) with moderate to severe acne found that isotretinoin (10-40 mg/day) + evening primrose oil (4 x 510 mg/day) improved total cholesterol (mean -6% vs. +21%), LDL (-33% vs. +37%), HDL (+12% vs. -2%), triglycerides (+3% vs. +24%), AST (-4% vs. +17%) and ALT (-4% vs. +14%) when compared to isotetinoin alone. [10713]
SupplementDEX Database · Menopause
9 references42.SupplementDEX Database: Menopause — Comparison of the Effect of Fennel and Evening Primrose Oil on Menopausal Problems and Hormonal Levels: A Randomized Controlled Trial2023
In 125 menopausal women over 8 weeks, fennel and evening primrose oil both significantly changed FSH and estradiol versus placebo; EPO also reduced Menopause Rating Scale scores more than placebo.
43.SupplementDEX Database: Menopause — Effect of Evening Primrose Oil on Postmenopausal Psychological Symptoms: A Triple-Blind Randomized Clinical Trial2021
In 100 postmenopausal women over 15 days, 2 g/day evening primrose oil significantly reduced psychological symptom scores on the Menopause Rating Scale versus control in a triple-blind RCT.
44.SupplementDEX Database: Menopause — The Effect of Evening Primrose Oil Capsule on Hot Flashes and Night Sweats in Postmenopausal Women: A Single-Blind Randomized Controlled Trial2021
In postmenopausal women taking 2,000 mg/day evening primrose oil for 8 weeks, hot flash duration, frequency, and severity did not differ from placebo, but night sweat frequency and severity decreased significantly with EPO.
46.SupplementDEX Database: Menopause — Impact of evening primrose oil consumption on psychological symptoms of postmenopausal women: a randomized double-blinded placebo-controlled clinical trial2020
In 189 postmenopausal women over 8 weeks, 1,000 mg/day evening primrose oil significantly reduced psychological Menopause Rating Scale scores versus placebo (mean difference −3.44, P<0.01).
47.SupplementDEX Database: Menopause — Efficacy and Safety of Nutraceutical on Menopausal Symptoms in Post-Menopausal Women: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial2020
In 101 postmenopausal women aged 45–60 over 12 weeks, a nutraceutical with soy isoflavones, black cohosh, chasteberry, and evening primrose oil reduced hot flushes, sweating, and irritability versus placebo.
48.SupplementDEX Database: Menopause — The effect of oral evening primrose oil on menopausal hot flashes: a randomized clinical trial2013
In 56 menopausal women over 6 weeks, 1,000 mg/day evening primrose oil reduced hot flash severity significantly more than placebo (42% vs 32% improvement), with smaller nonsignificant gains in frequency and duration.
49.SupplementDEX Database: Menopause — Effect of a compound containing isoflavones, primrose oil and vitamin E in two different doses on climacteric symptoms2006
In 1,080 postmenopausal women, one or two daily capsules of isoflavones 60 mg plus primrose oil 440 mg and vitamin E 10 mg significantly reduced Blatt-Kupperman climacteric scores over 3–6 months.
50.SupplementDEX Database: Menopause — Effect of oral gamolenic acid from evening primrose oil on menopausal flushing1994
In 56 menopausal women over 6 months, 4,000 mg/day evening primrose oil did not reduce hot flushes more than liquid paraffin placebo; placebo showed greater daytime flush reduction (1.9 vs 0.5 episodes/month).
45.The Effects of Evening-Primrose Oil on Menopausal Symptoms: A Systematic Review and Meta-analysis of Randomized Controlled Trials. See external sourceExternal source