Gamma-Linolenic Acid
GLA is an omega-6 fatty acid from oils like borage and evening primrose. Evidence varies by condition and dose.
Overview
What is gamma-linolenic acid?
Gamma-linolenic acid (GLA) is an omega-6 polyunsaturated fatty acid.
Dosage
A typical oral dose of GLA is 320-480 mg per day.
Effect graph
Effect heatmap
SupplementDEX Database
12 conditions for and rated at least stars. All purchase bands. No minimum star filter.
Database Snapshot
Most gamma-linolenic acid research is concentrated in a handful of conditions.
- Acute respiratory distress syndrome accounts for 3 of 18 studies (17%).
- Eczema accounts for 3 of 18 studies (17%).
- Diabetic neuropathy accounts for 2 of 18 studies (11%).
- Sparse coverage remains for Diabetic neuropathy, Hypertension, Asthma.
Dietary Sources
Top dietary sources
Food sources
Sources include Barley, Blackcurrant Seed Oil, Breast Milk, Evening Primrose Oil, Oats, Spirulina, and The Diet From Sources Including Borage Oil.
Safety
Oral gamma-linolenic acid is possibly safe at a dose of 2.8 grams per day for 1 year.
Frequently Asked Questions
References
Sources18 references
SupplementDEX uses only high-quality sources to determine supplement effectiveness.
SupplementDEX Database · Diabetic neuropathy
2 references1.SupplementDEX Database: Diabetic neuropathy — Treatment of diabetic neuropathy with gamma-linolenic acid. The gamma-Linolenic Acid Multicenter Trial Group1993
In a 1-year double-blind RCT of 111 diabetic patients with mild neuropathy, 480 mg/day GLA improved 13 of 16 nerve function parameters versus placebo.
2.SupplementDEX Database: Diabetic neuropathy — The effect of gamma-linolenic acid on human diabetic peripheral neuropathy: a double-blind placebo-controlled trial1990
In a 6-month double-blind trial of 22 diabetic neuropathy patients, 360 mg/day GLA improved symptom scores, motor nerve conduction velocity, and CMAP amplitude versus placebo.
SupplementDEX Database · Eczema
3 references3.SupplementDEX Database: Eczema — Dietary supplementation of gamma-linolenic acid improves skin parameters in subjects with dry skin and mild atopic dermatitis2011
In adults with dry skin or mild atopic dermatitis, GLA-rich oil supplementation improved transepidermal water loss, with greater benefit in those with pro-inflammatory features.
4.SupplementDEX Database: Eczema — Oral essential fatty acid supplementation in atopic dermatitis-a meta-analysis of placebo-controlled trials2004
A meta-analysis of 19 GLA and 5 fish oil eczema trials found pooled effect size for GLA on overall severity was 0.15 (95% CI −0.02 to 0.32), indicating no clinically relevant benefit.
5.SupplementDEX Database: Eczema — The efficacy and safety of gamma-linolenic acid in the treatment of infantile atopic dermatitis1994
In an open 28-day trial of infants with atopic dermatitis, 3 g/day GLA gradually improved erythema, excoriations, and itching, though no child achieved complete recovery.
6.SupplementDEX Database: Acute respiratory distress syndrome — Immunonutrition for acute respiratory distress syndrome (ARDS) in adults2019
A meta-analysis of RCTs in mechanically ventilated ARDS adults found insufficient consistent evidence that immunonutrition formulas improve mortality or ventilator-free days versus standard feeding.
7.SupplementDEX Database: Acute respiratory distress syndrome — Omega-3 polyunsaturated fatty acids in critically ill patients with acute respiratory distress syndrome: A systematic review and meta-analysis2019
An updated meta-analysis of RCTs in ARDS patients found omega-3 PUFA-enriched enteral nutrition did not consistently improve gas exchange or clinical outcomes versus standard nutrition.
8.SupplementDEX Database: Acute respiratory distress syndrome — Enteral Immunomodulatory Diet (Omega-3 Fatty Acid, γ-Linolenic Acid and Antioxidant Supplementation) for Acute Lung Injury and Acute Respiratory Distress Syndrome: An Updated Systematic Review and Meta-Analysis2015
A meta-analysis of 6 RCTs in ALI/ARDS patients found enteral immunomodulatory diets with omega-3, gamma-linolenic acid, and antioxidants did not significantly reduce overall mortality versus control.
SupplementDEX Database · Asthma
1 reference9.SupplementDEX Database: Asthma — The impact of a medical food containing gammalinolenic and eicosapentaenoic acids on asthma management and the quality of life of adult asthma patients2008
In an RCT of 35 adults with mild-to-moderate asthma, a medical food with 0.75–1.13 g/day GLA plus EPA did not clearly improve asthma management or quality-of-life scores over 4 weeks versus placebo.
10.SupplementDEX Database: Attention deficit hyperactivity disorder (ADHD) — Omega-3/6 supplementation for mild to moderate inattentive ADHD: a randomised, double-blind, placebo-controlled efficacy study in Italian children2022
In a 6-month double-blind RCT of 160 Italian children (ages 6–12) with inattentive ADHD, omega-3/6 supplement (558 mg EPA + 174 mg DHA + 60 mg GLA/day) improved inattention scores versus placebo.
SupplementDEX Database · Back pain
1 reference11.SupplementDEX Database: Back pain — The use of alpha-lipoic acid (ALA), gamma linolenic acid (GLA) and rehabilitation in the treatment of back pain: effect on health-related quality of life2009
In a cohort of 203 back-pain patients, alpha-lipoic acid plus 600 mg/day GLA with rehabilitation reduced neuropathic pain and improved quality of life versus rehabilitation alone.
SupplementDEX Database · Breast cancer
1 reference12.SupplementDEX Database: Breast cancer — Gamma linolenic acid with tamoxifen as primary therapy in breast cancer2000
In 38 breast cancer patients on tamoxifen, adding 2.8 g/day GLA produced faster clinical responses and greater tumor marker improvements than tamoxifen alone in this small controlled trial.
SupplementDEX Database · Hypertension
2 references13.SupplementDEX Database: Hypertension — A trial of omega-3 fatty acids for prevention of hypertension2004
In a randomized trial of adults with high-normal diastolic blood pressure, a novel omega-3 fatty acid supplement did not significantly reduce blood pressure versus placebo.
14.SupplementDEX Database: Hypertension — The antihypertensive effect of dietary supplementation with a 6-desaturated essential fatty acid concentrate as compared with sunflower seed oil1992
In 18 volunteers with elevated blood pressure, 4 g/day of a 6-desaturated essential fatty acid concentrate (GLA, EPA, DHA) lowered blood pressure compared with 4 g/day sunflower oil over 6 weeks.
SupplementDEX Database · Mastalgia
1 reference15.SupplementDEX Database: Mastalgia — Open-Label Three Arm Trial Comparing Ormeloxifene, Gamma Linolenic Acid With Methylcobalamine + Vitamin C and Placebo in Mastalgia2022
In a 12-week open-label RCT of 113 women with mastalgia, GLA plus methylcobalamin and vitamin C achieved complete relief in 94%, similar to ormeloxifene (96%) and placebo (87%).
SupplementDEX Database · Rosacea
1 reference16.SupplementDEX Database: Rosacea — A Randomized, Placebo-Controlled Trial of Gamma Linolenic Acid as an Add-on Therapy to Minocycline for the Treatment of Rosacea2020
In a 12-week double-blind RCT of 31 rosacea patients on minocycline, adding 320 mg/day GLA did not clearly improve IGA or PGA scores beyond minocycline alone.
SupplementDEX Database · Scleroderma
1 reference17.SupplementDEX Database: Scleroderma — Clinical aspects of the use of gamma linolenic acid in systemic sclerosis1996
In a 6-month double-blind RCT of 25 systemic sclerosis patients, concentrated essential fatty acids did not improve vascular reactivity or Raynaud symptoms versus placebo.
SupplementDEX Database · Ulcerative colitis
1 reference18.SupplementDEX Database: Ulcerative colitis — A double-blind, randomized, placebo-controlled trial of essential fatty acid supplementation in the maintenance of remission of ulcerative colitis2002
In a 12-month double-blind RCT of quiescent ulcerative colitis patients, daily GLA (1.6 g) plus EPA and DHA did not significantly reduce relapse rates versus 500 mg/day sunflower oil placebo.