Is evening primrose oil safe during perimenopause?

Evening primrose oil (EPO) is extracted from the seeds of the Oenothera biennis plant and is rich in gamma-linolenic acid (GLA), an omega-6 fatty acid. It has been promoted for breast tenderness, PMS symptoms, and hot flashes during perimenopause for decades. Safety-wise, EPO is generally well-tolerated, but it has several important interactions and limitations in evidence that are worth understanding clearly.

What might EPO do during perimenopause?

GLA is a precursor to certain anti-inflammatory prostaglandins, and EPO's anti-inflammatory pathway is the theoretical basis for its use in breast tenderness (mastalgia) and cyclical breast pain. There is modest clinical evidence supporting EPO for cyclical mastalgia, which is a common perimenopause complaint. For hot flashes, a randomized controlled trial (Farzaneh et al., 2013) found that EPO reduced hot flash severity but not frequency compared to placebo. Other studies have been less convincing. The evidence base is limited but not absent.

Key safety considerations

Hormone-sensitive conditions: EPO has potential prolactin-stimulating effects at higher doses, and some sources caution about use in hormone-sensitive conditions. This is less definitively established than for some other herbs, but women with hormone receptor-positive breast cancer or a history of it should discuss EPO with their oncologist.

Blood thinning and bleeding risk: GLA has mild antiplatelet (anti-clotting) effects, meaning EPO can slightly increase bleeding time. This is particularly relevant for women taking blood thinners (warfarin, aspirin, clopidogrel, or newer anticoagulants), NSAIDs, or fish oil, as combined effects on bleeding can be additive. Discontinue EPO at least 2 weeks before surgery.

Seizure risk: There are case reports of evening primrose oil triggering seizures in people with epilepsy or in those taking phenothiazine medications. This is considered rare but warrants awareness.

Pregnancy: EPO is not recommended in pregnancy due to possible effects on uterine contractions.

Typically studied doses range from 1 to 4 grams per day. Side effects are generally mild (nausea, soft stools, headache) and dose-dependent. Quality varies between brands, and rancidity of the oil (which produces harmful oxidation products) is a concern with poorly stored or low-quality products. Refrigerating EPO after opening and checking production and expiry dates is advisable.

GLA, inflammation, and skin health during perimenopause

Beyond its effects on breast tenderness and hot flashes, EPO's GLA content has relevance for skin health during perimenopause. Declining estrogen reduces skin lipid production, contributing to dryness, increased sensitivity, and worsening of inflammatory skin conditions like eczema in some women. GLA supports skin barrier function and reduces skin inflammation through its conversion to anti-inflammatory prostaglandins. Women who notice increasing skin dryness or eczema flares alongside perimenopausal hormonal changes may find EPO's GLA content helpful for skin symptoms even if the hot flash evidence is modest. This is a less commonly discussed but biologically supported potential benefit.

Fish oil versus evening primrose oil

Both fish oil (containing EPA and DHA, omega-3 fatty acids) and EPO (containing GLA, an omega-6 fatty acid) have anti-inflammatory effects, but through different pathways. Fish oil has a much larger body of clinical evidence across many health outcomes. For women uncertain about which oil supplement to prioritize, fish oil generally has stronger evidence. EPO and fish oil can be used together, but combined antiplatelet effects should be considered, particularly in women on blood thinners or aspirin.

Tracking your symptoms over time using an app like PeriPlan can help you assess whether breast tenderness or hot flash severity is genuinely changing over a 2 to 3 month trial period.

When to talk to your doctor

Discuss EPO with your doctor if you take blood thinners, antiplatelet drugs, or NSAIDs; if you have epilepsy or take medications for seizures; if you have a history of hormone-sensitive cancers; or if you are planning surgery. Also discuss it if you are taking phenothiazine-based medications.

This content is for informational purposes only and does not replace medical advice. Always consult your healthcare provider about your specific situation.