Evening Primrose Oil (GLA)

A GLA source popular for PMS, breast pain, and eczema — mostly modest or null on rigorous review.

Overall grade: Grade C
Last revised: Jul 10, 2026; 2
graded outcomes: 0
references listed

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A structured monograph in Prometheus's bundled library. Its grades are the monograph's own reading of the evidence, not a peer-reviewed review.

2 at grade C · 1 at grade D — 3 graded rows

What is known

Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.

Outcome	Grade	Effect size	Agreement
PMS / breast painMixed	Evidence grade C	Small	mixed
EczemaReviews null	Evidence grade D	Trivial	high

PMS / breast painEvidence grade C
Mixed
Smallmixed
EczemaEvidence grade D
Reviews null
Trivialhigh

Conditions

How the entry reads its effect on diagnosed conditions: the direction first, then the grade. Never a substitute for the person who treats you.

PMS May improveEvidence grade CInconsistentGrade C

What is uncertain

Read off the same rows as above. Nothing here is added that the entry does not itself record.

Thin evidence: PMS / breast pain (grade C); Eczema (grade D).

The evidence in words

What it is

Evening primrose oil supplies gamma-linolenic acid (GLA), an omega-6 used for hormonal and skin symptoms.

How it works

GLA feeds anti-inflammatory prostaglandin pathways.

What the evidence shows

Rigorous reviews find little benefit for eczema and mixed results for PMS and cyclical breast pain, though some individuals report relief. Safe but underwhelming.

How to use it

Standardized GLA dose daily, given several weeks.

Safety & interactions

Generally safe; mild antiplatelet action; caution with seizure threshold in some.

Bottom line

Popular for PMS and skin, weak on hard evidence. Low-risk to trial; temper expectations.

How it is used

As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.

Standard: Standardized GLA daily.

Entries that share this one's tags or conditions.

Evening Primrose Oil (GLA) for PMSEvidence grade C — InconsistentEvidence grade C
Evening Primrose Oil (GLA) for EczemaEvidence grade D — Reviews nullEvidence grade D
Evening Primrose Oil (GLA) for PMS / breast painEvidence grade C — MixedEvidence grade C
Evening Primrose Oil (GLA): dosage and how to take itStandardized GLA daily.Evidence grade C

Sources

This entry lists no references of its own.

Last revised Jul 10, 2026. A grade is this entry's reading of the evidence, not medical advice.