GLA
Research reviewed: Up until 03/2026
GLA (Gamma-Linolenic Acid) is a dietary supplement with 7 published peer-reviewed studies involving 1,180 participants, researched for Skin Health, Anti-inflammatory Effects, Rheumatoid Arthritis and 1 more areas.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Skin Health
StrongAnti-inflammatory Effects
ModerateRheumatoid Arthritis
StrongHormonal Balance
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Skin Health
To evaluate GLA supplementation on eczema (atopic dermatitis) symptoms.
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate GLA supplementation on eczema (atopic dermatitis) symptoms.
Dose
360 mg/day GLA (from evening primrose oil)
Participants
160 children and adults with atopic eczema
Duration
16 weeks
Results
GLA supplementation significantly reduced SCORAD and itch scores compared to placebo. TEWL improved, indicating enhanced skin barrier function. Children showed greatest benefit.
How They Measured It
SCORAD (Scoring Atopic Dermatitis), TEWL (transepidermal water loss), itch VAS
To systematically evaluate GLA supplementation for atopic eczema.
Study Type
Meta-analysis
Purpose
To systematically evaluate GLA supplementation for atopic eczema.
Dose
Various GLA sources
Participants
Pooled from 9 RCTs
Duration
Various
Results
GLA supplementation produced significant improvements in eczema severity scores and skin barrier function. The effect was moderate and consistent across studies, with greater effects in children.
How They Measured It
Pooled SCORAD, symptom severity, TEWL across RCTs
Anti-inflammatory Effects
To examine the mechanism by which GLA exerts anti-inflammatory effects.
Study Type
In-vitro study
Purpose
To examine the mechanism by which GLA exerts anti-inflammatory effects.
Dose
Various GLA concentrations
Participants
Human peripheral blood mononuclear cells
Duration
N/A
Results
GLA is rapidly converted to DGLA (dihomo-GLA), which produces anti-inflammatory 15-HETrE and competes with arachidonic acid for COX and LOX enzymes, reducing pro-inflammatory eicosanoid production.
How They Measured It
DGLA metabolite production (15-HETrE), eicosanoid analysis, COX pathway activity
To evaluate GLA supplementation on systemic inflammatory markers.
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate GLA supplementation on systemic inflammatory markers.
Dose
4 g/day GLA
Participants
68 healthy adults
Duration
12 weeks
Results
GLA supplementation significantly reduced CRP and leukotriene B4 compared to placebo. IL-6 and TNF-α showed non-significant trends toward reduction, consistent with anti-inflammatory activity.
How They Measured It
CRP, IL-6, TNF-α, leukotriene B4
Rheumatoid Arthritis
To assess GLA from borage oil on disease activity in rheumatoid arthritis.
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To assess GLA from borage oil on disease activity in rheumatoid arthritis.
Dose
2.8 g/day GLA (from borage oil)
Participants
56 patients with rheumatoid arthritis
Duration
24 weeks
Results
GLA supplementation significantly reduced joint tenderness and swelling compared to placebo. ACR20 response rate was significantly higher in the GLA group. GLA from borage oil is an effective anti-inflammatory treatment for RA.
How They Measured It
ACR response criteria, tender joint count, swollen joint count, DAS28
To compare GLA combined with fish oil versus fish oil alone in rheumatoid arthritis.
Study Type
Randomised, controlled trial
Purpose
To compare GLA combined with fish oil versus fish oil alone in rheumatoid arthritis.
Dose
2.0 g/day GLA + EPA/DHA vs EPA/DHA alone
Participants
74 RA patients
Duration
9 months
Results
The combination of GLA plus fish oil produced significantly greater reductions in disease activity than fish oil alone. GLA potentiated the anti-inflammatory effects of omega-3s through complementary mechanisms.
How They Measured It
ACR response, disease activity scores, NSAID use
Hormonal Balance
To evaluate GLA (evening primrose oil) supplementation on premenstrual syndrome symptoms.
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate GLA (evening primrose oil) supplementation on premenstrual syndrome symptoms.
Dose
3 g/day GLA from evening primrose oil
Participants
120 women with PMS
Duration
3 menstrual cycles
Results
GLA supplementation significantly reduced breast tenderness, mood disturbances, and bloating in women with PMS. Elevated prostaglandin E1 production is proposed as the mechanism for hormonal balance effects.
How They Measured It
PMS symptom diary (breast tenderness, mood, bloating), prostaglandin E1 levels
Frequently Asked Questions
Common questions about GLA research
There are currently 9 peer-reviewed studies on GLA (Gamma-Linolenic Acid), involving 1,180 total participants. Research covers Skin health, Anti-inflammatory effects, Rheumatoid arthritis and 1 more areas. The overall evidence strength is rated as Very Strong.
The evidence is currently rated as "Very Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (6 human studies), and reported outcomes.
GLA has been researched for: Skin health, Anti-inflammatory effects, Rheumatoid arthritis, Hormonal balance. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 6 out of 9 studies are human trials. Human trials carry more weight in our evidence scoring system.
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