- Evening primrose oil
- Night willow herb
- Fever plant
- King's cure-all
For Patients & Caregivers
Tell your healthcare providers about any dietary supplements you’re taking, such as herbs, vitamins, minerals, and natural or home remedies. This will help them manage your care and keep you safe.
What is it?
Evening primrose is a plant that was used by Native Americans to heal wounds, bruises, and to soothe swollen skin. They would eat the leaves to help with sore throats and stomach issues.
Evening primrose oil supplements come as softgels, capsules, and liquids. It’s also added to creams and ointments that you can put on your skin.
What is it used for?
Evening primrose oil is used to:
- Treat dermatitis (a type of eczema that makes your skin red, itchy, and swollen)
- Relieve pain caused by arthritis
- Treat breast pain
- Treat menstrual symptoms (symptoms caused by your monthly period) such as bloating and headaches
- Treat symptoms caused by menopause (permanent end of menstrual cycles) such as hot flashes
- Treat nerve damage caused by diabetes
Evening primrose oil also has other uses but they haven’t been studied by doctors to see if they work.
Talk with your healthcare provider before taking evening primrose oil supplements. They can interact with some medications and affect how they work. For more information, read the “What else do I need to know?” section below.
What are the side effects?
What else do I need to know?
- Talk with your healthcare provider if you’re taking blood thinners such as warfarin (Coumadin®, Jantoven®). Evening primrose oil may increase your risk of bleeding.
- Talk with your healthcare provider if you’re taking medication to lower your blood pressure. Evening primrose oil can increase your blood pressure.
- Talk to your healthcare provider if you’re taking the HIV medication lopinavir (Kaletra®). Evening primrose oil may affect how it works.
- Talk with your healthcare provider if you’re pregnant or breastfeeding. It may increase the risk of complications.
For Healthcare Professionals
Derived from the plant Oenothera biennis, evening primrose oil is used for rheumatoid arthritis, premenstrual syndrome, eczema, fatigue, diabetic neuropathy, and mastalgia. The mucilaginous stem and leaf juices have been used as a poultice to treat minor bruises and wounds, and soothe skin inflammation (25). Evening primrose oil is thought to improve skin moisture and reduce transepidermal water loss (26). It is also among the popular natural products used to relieve menopausal symptoms (27) (28). In vitro, evening primrose oil demonstrates anti-inflammatory activity (29) and inhibits platelet aggregation (6) (7). In animal models, it exerts anti-angiogenic, anti-inflammatory, and anti-arthritic effects (30), and improved cardiac recovery after myocardial infarction (31).
Human studies on whether evening primrose oil is helpful for skin conditions are limited and mixed. Small trials suggest benefit in atopic dermatitis (18) (25) (32), but other analyses did not find evening primrose oil or borage oil effective for eczema (23) (33). In acne patients treated with oral isotretinoin, evening primrose oil may improve xerotic cheilitis (34). It may also reduce 5-azacitidine-induced skin reactions in patients with myelodysplastic syndrome (19). Other preliminary data suggest benefit in some lipid profiles (53), rheumatoid arthritis symptoms (21), ulcerative colitis (35) (36), or for ocular surface diseases such as dry eye (37) (38), but early studies in diabetic neuropathy were equivocal (39). In multiple sclerosis patients, it may improve fatigue and quality of life (54), and along with hemp seed and a diet high in antioxidants, it may improve clinical and immunological parameters (40) (41) (42).
Additional data indicate that supplementation with vitamin E and evening primrose oil reduced cyclical mastalgia (20), but other analyses did not find improvements in breast pain (1) (43) or premenstrual syndrome (22). Evening primrose oil may improve quality of life and decrease hot flash intensity in menopausal women (44), although other data suggest that behavioral/lifestyle approaches such as exercise provide better relief (28). In postmenopausal women, it improved related psychological symptoms (55), but more study is needed to confirm these effects.
Studies in cancer patients are quite limited, with one trial involving liver cancer patients that showed no effect on tumor size or survival (45), and another that suggested gamma-linolenic acid may be an effective adjunctive therapy for breast cancer (4). Although evening primrose oil does not have intrinsic estrogenic properties, some commercial products combine evening primrose oil with phytoestrogens. Therefore, patients with hormone-sensitive cancers should use evening primrose oil products with caution.
Mechanism of Action
Evening primrose oil is rich in omega-6 gamma-linolenic acid (GLA), which can be converted directly to the prostaglandin precursor dihomo-GLA (DGLA) (2) (3). Administration of the oil may benefit individuals unable to metabolize cis-linolenic acid to GLA, producing subsequent intermediates of metabolic significance including prostaglandins (2) (3).
In vitro, long-chain fatty alcohols such as hexacosanol, tetracosanol, docosanol, and octocosanol demontrate anti-inflammatory activity (29). In animal models, benefits on cardiac recovery after myocardial infarction are attributed to its hypocholesterolemic effect and indirect influence on prostaglandins and cytokine synthesis (31). In arthiritis models, evening primrose oil normalized body weight, angiopoietin-1, and tumor necrosis factor-alpha levels, and reduced malondialdehyde levels, synovial hyperplasia, and inflammatory cell invasion in joint tissues (30).
In patients with multiple sclerosis, evening primrose oil accelerates anti-inflammatory responses and prevents pro-inflammatory cytokine production while helping to maintain fatty acid membranes and optimizing balance between saturated and unsaturated fatty acids (40). Increases in plasma GLA and its metabolite DGLA seen with evening primrose oil supplementation has correlated with clinical improvements in atopic dermatitis (32) and produced dose-dependent effects on serum fatty acid levels and eczema severity scores (25). Inhibition of cheilitis is attributed to GLA’s effects on stratum corneum maturation, differentiation, and preservation of its permeability barrier (34). Antiplatelet and anticoagulant effects are likely related to decreased thromboxane B2 synthesis induced by evening primrose oil (46) (47).
- Pregnant women should not take evening primrose oil due to increased risk of pregnancy complications (8) (48).
- Patients with hormone-sensitive cancers should use evening primrose oil products with caution, because even though it does not possess estrogenic properties on its own, some commercial evening primrose oil products may contain other phytoestrogen ingredients.
Minor: abdominal pain, indigestion, nausea, softening of stools, and headaches (25).
Labor abnormalities: When used to shorten gestation and length of labor, increased incidences of prolonged membrane rupture, oxytocin augmentation, arrest of descent, and vacuum extraction (8) (48).
Petechiae and ecchymoses: Observed in a newborn whose mother used raspberry leaf tea and evening primrose oil vaginally and orally 1 week before childbirth (12).
Lipoid pneumonia: In a 50-year-old woman following chronic use of evening primrose oil, caused by aspiration of lipid particles into the lungs (24).
Anticoagulants/Antiplatelets: May have additive effects and increase bleeding risk (46) (49). In a small study of humans on several months of supplementation with y-linoleic acid from evening primrose oil, a significant increase in bleeding time was observed in 9 of 12 patients (47). Evening primrose oil is about 10% GLA (52).
Blood pressure medications: Although there are no interactions reported with blood pressure medications, evening primrose oil was identified as being among supplements that may increase both systolic and diastolic blood pressures, with a clinically meaningful difference for systolic blood pressure in a large population-based study (50).
Antiretrovirals: In humans, evening primrose oil significantly increases the levels of antiretroviral drugs and may increase the risk of adverse effects (51).