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Gamma-Linolenic Acid (GLA)
What is it? Overview Usage Side Effects and Warnings

Gamma-Linolenic Acid (GLA) Usage

Written by FoundHealth.

Therapeutic Uses

GLA has shown some promise for the treatment of diabetic neuropathy , 1 a complication of diabetes . This condition consists of pain and/or numbness due to progressive nerve damage. However, supporting evidence that GLA is effective for this use is quite limited.

Perhaps the most common use of GLA has been as a treatment for eczema . It was once widely dispensed for this purpose by the British healthcare system, but the balance of the evidence indicates that for eczema, GLA is just a placebo treatment. 2 GLA is also a popular treatment for cyclic mastalgia (breast pain that cycles with the menstrual period), but the evidence regarding its effectiveness is more negative than positive. 3 GLA is additionally said to be useful for general premenstrual syndrome (PMS) symptoms, but the supporting evidence for this use is very weak. 4 Despite many positive anecdotes, 5 GLA has failed to prove effective for attention deficit and hyperactivity disorder (ADHD) . 6 One study that used GLA plus fish oil did find weak evidence of benefits. 7 Extremely weak evidence hints that evening primrose oil might be more effective for ADHD if combined with zinc, but this is more of an untested hypothesis than a conclusion. 8 GLA has been studied for numerous other conditions, such as rheumatoid arthritis , 9 10 11 Raynaud's phenomenon (a condition in which the fingers and toes react to cold in an exaggerated way), 12 weight loss , 13 ulcerative colitis , 14 kidney stones , 15 multiple sclerosis , 16 and increasing the effectiveness of the drug tamoxifen in the treatment of breast cancer . 17 Note: Individuals undergoing treatment for cancer should not take GLA (or any other supplement) except under physician supervision.

Other studies have investigated the potential benefits of combination treatment using GLA and fish oil. Conditions studied include osteoporosis , 18 chronic fatigue syndrome , 19 periodontitis (gum disease), 20 and Huntington’s disease. In these trials, some promising (but far from definitive) results have been seen. However, this combination therapy has failed to prove effective for cyclic mastalgia . 21 GLA is sometimes suggested as a treatment for tardive dyskinesia , but two double-blind studies have failed to find it helpful for this disorder. 22 GLA has also failed to prove effective for the itching caused by kidney dialysis. 23 There is some evidence that GLA may benefit patients with eye problems. One randomized trial indicated that orally administered evening primrose oil was more effective than olive oil (placebo) at reducing dry eye symptoms and improving comfort in users of soft contact lens. 24 In addition, Sjogren's syndrome , an autoimmune condition in which the immune system destroys moisture-producing glands, often causes dry eyes due to lack of tears. One small double-blind study found that a combination of GLA and the omega-6 fatty acid linoleic acid (found in many vegetable oils) may improve dry eye symptoms in Sjogren's. 25 Finally, patients who undergo laser surgery for vision correction (photorefractive keratectomy) are sometimes left with a hazy appearance to their cornea. Another small randomized trial found some potential benefit of a supplement containing omega-6 fatty acids in preventing this complication. 26 Thus far, we've mentioned only a fraction of the conditions for which GLA has been proposed as a treatment. Others include: asthma , allergies , bursitis , endometriosis , heart disease , irritable bowel syndrome , prostate cancer , benign prostatic hyperplasia (BPH) , and Sjogren's disease . However, none of these potential uses has as yet been scientifically evaluated to any significant extent.


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  2. Morse PF, Horrobin DF, Manku MS, Stewart JC, Allen R, Littlewood S, Wright S, Burton J, Gould DJ, Holt PJ. Meta-analysis of placebo-controlled studies of the efficacy of Epogam in the treatment of atopic eczema. Relationship between plasma essential fatty acid changes and clinical response. Br J Dermatol. 121(1):75-90.
  3. Pashby NL, Mansel RE, Hughes LE, et al. A clinical trial of evening primrose oil in mastalgia [abstract]. Br J Surg. 1981;68:801.
  4. Budeiri D, Li Wan Po A, Dornan JC. Is evening primrose oil of value in the treatment of premenstrual syndrome? Control Clin Trials. 17(1):60-8.
  5. Richardson AJ, McDaid AM, Calvin CM, et al. Reduced behavioural and learning problems in children with specific learning difficulties after supplementation with highly unsaturated fatty acids: a randomized double-blind placebo-controlled trial. Presented at: 2nd Forum of European Neuroscience Societies; July 24-28, 2000; Brighton, United Kingdom.
  6. Aman MG, Mitchell EA, Turbott SH. The effects of essential fatty acid supplementation by Efamol in hyperactive children. J Abnorm Child Psychol. 15(1):75-90.
  7. Stevens L, Zhang W, Peck L, Kuczek T, Grevstad N, Mahon A, Zentall SS, Arnold LE, Burgess JR. EFA supplementation in children with inattention, hyperactivity, and other disruptive behaviors. Lipids. 38(10):1007-21.
  8. Arnold LE, Pinkham SM, Votolato N. Does zinc moderate essential fatty acid and amphetamine treatment of attention-deficit/hyperactivity disorder? J Child Adolesc Psychopharmacol. 10(2):111-7.
  9. Zurier RB, Rossetti RG, Jacobson EW, DeMarco DM, Liu NY, Temming JE, White BM, Laposata M. gamma-Linolenic acid treatment of rheumatoid arthritis. A randomized, placebo-controlled trial. Arthritis Rheum. 39(11):1808-17.
  10. Leventhal LJ, Boyce EG, Zurier RB. Treatment of rheumatoid arthritis with blackcurrant seed oil. Br J Rheumatol. 33(9):847-52.
  11. Leventhal LJ, Boyce EG, Zurier RB. Treatment of rheumatoid arthritis with gammalinolenic acid. Ann Intern Med. 119(9):867-73.
  12. Belch JJ, Shaw B, O'Dowd A, et al. Evening primrose oil (Efamol) as a treatment for cold-induced vasospasm (Raynaud's phenomenon). Prog Lipid Res. 1986;25:335-340.
  13. Haslett C, Douglas JG, Chalmers SR, Weighhill A, Munro JF. A double-blind evaluation of evening primrose oil as an antiobesity agent. Int J Obes. 7(6):549-53.
  14. Greenfield SM, Green AT, Teare JP, Jenkins AP, Punchard NA, Ainley CC, Thompson RP. A randomized controlled study of evening primrose oil and fish oil in ulcerative colitis. Aliment Pharmacol Ther. 7(2):159-66.
  15. Tamimi NA, Mikhail AI, and Stevens PE. Role of gamma-linolenic acid in uraemic pruritus [letter]. Nephron. 1999;83:170-171.
  16. Horrobin DF. Multiple sclerosis: the rational basis for treatment with colchicine and evening primrose oil. Med Hypotheses. 5(3):365-78.
  17. Kenny FS, Pinder SE, Ellis IO, Gee JM, Nicholson RI, Bryce RP, Robertson JF. Gamma linolenic acid with tamoxifen as primary therapy in breast cancer. Int J Cancer. 85(5):643-8.
  18. Kruger MC, Coetzer H, de Winter R, Gericke G, van Papendorp DH. Calcium, gamma-linolenic acid and eicosapentaenoic acid supplementation in senile osteoporosis. Aging (Milano). 10(5):385-94.
  19. Behan PO, Behan WM, Horrobin D. Effect of high doses of essential fatty acids on the postviral fatigue syndrome. Acta Neurol Scand. 82(3):209-16.
  20. Rosenstein ED, Kushner LJ, Kramer N, Kazandjian G. Pilot study of dietary fatty acid supplementation in the treatment of adult periodontitis. Prostaglandins Leukot Essent Fatty Acids. 68(3):213-8.
  21. Blommers J, de Lange-De Klerk ES, Kuik DJ, Bezemer PD, Meijer S. Evening primrose oil and fish oil for severe chronic mastalgia: a randomized, double-blind, controlled trial. Am J Obstet Gynecol. 187(5):1389-94.
  22. Vaddadi K. Dyskinesias and their treatment with essential fatty acids: a review. Prostaglandins Leukot Essent Fatty Acids. 1996;55:89-94.
  23. Tamimi NA, Mikhail AI, Stevens PE. Role of gamma-linolenic acid in uraemic pruritus [letter]. Nephron. 1999;83:170-171.
  24. Kokke KH, Morris JA, Lawrenson JG. Oral omega-6 essential fatty acid treatment in contact lens associated dry eye. Cont Lens Anterior Eye. 31(3):141-6; quiz 170.
  25. Aragona P, Bucolo C, Spinella R, Giuffrida S, Ferreri G. Systemic omega-6 essential fatty acid treatment and pge1 tear content in Sjögren's syndrome patients. Invest Ophthalmol Vis Sci. 46(12):4474-9.
  26. Querques G, Russo V, Barone A, Iaculli C, Delle Noci N. [Efficacy of omega-6 essential fatty acid treatment before and after photorefractive keratectomy] J Fr Ophtalmol. 31(3):282-6.


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