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SupplementModerate evidenceImmunity

Evening primrose oil

Gamma-linolenic acid source with modest signal for cyclic mastalgia and a withdrawn historical eczema indication.

Why

Evening primrose oil (Oenothera biennis seed oil) is a rich source of gamma-linolenic acid (GLA). The most consistent RCT signal is in cyclic mastalgia, modest reductions in breast pain severity at 3–4 g/day over 3–6 months. The historical UK licence for atopic eczema (Epogam) was withdrawn in 2002 after Cochrane review found no consistent effect. Modern use is mostly for breast pain and as a GLA source in atopic skin.

How it works

GLA is the immediate precursor of dihomo-gamma-linolenic acid and prostaglandin E1, with downstream anti-inflammatory effects. In cyclic mastalgia, this may correct the abnormal prolactin-prostaglandin balance proposed as the underlying mechanism.

Expected onset · Cyclic mastalgia: effect emerges over 3–6 cycles (8–24 weeks)

How to take

Dosage

Cyclic mastalgia: 3–4 g/day (delivering ~270–360 mg GLA), divided across the day. Atopic skin: 4–6 g/day.

Timing

Divided with meals

On the label

Stated GLA content per capsule (typically 9–10% of total oil). Cold-pressed, refrigerated storage preserves activity.

Ideal for

Women with troublesome cyclic mastalgia; people with atopic skin seeking a dietary fatty-acid approach.

Safety

Theoretical seizure threshold concerns at high doses. Caution in epilepsy. Possible antiplatelet effect at high doses. Stop 2 weeks before surgery. Mild GI upset (nausea, soft stools). Pregnancy data limited, some traditional use for cervical ripening means it should be avoided in early pregnancy.

Evidence

At a glance

Pruthi 2010 Altern Med Rev meta-analysis: evening primrose oil produced modest reductions in cyclic mastalgia severity, with effect comparable to bromocriptine but slower onset. Cochrane 2013 SR on atopic eczema found no consistent benefit, the historical UK licence was withdrawn. Mastalgia remains the indication with the more consistent positive signal.

Where to get it

Shop Evening primrose oil on Amazon

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