Evening Primrose Oil
Scientific Name(s): Oenothera biennis L. Family: Onagraceae 1
Common Name(s): Evening primrose , common evening primrose
Clinical Overview
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 User Reviews & Ratings
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Uses of Evening Primrose Oil
There is some evidence to suggest that evening primrose oil is effective for treating rheumatoid arthritis and diabetic neuropathy.
Evening Primrose Oil Dosing
Evening primrose oil has been administered orally in clinical trials at doses between 6 and 8 g/day in adults and 2 and 4 g/day in children. 2 , 3 , 4 The typical content of gamma-linolenic acid (GLA) in the oil is 8% to 10%. 5
Contraindications
No contraindications have yet been identified.
Pregnancy/Lactation
Information regarding safety and efficacy in pregnancy and lactation is lacking. Both linoleic and gamma-linolenic acid are normally present in breast milk, and it is reasonable to assume that evening primrose oil may be taken while breast-feeding.
Evening Primrose Oil Interactions
None well documented.
Evening Primrose Oil Adverse Reactions
Evening primrose oil is suspected to lower the seizure threshold in epileptic patients. 6 , 7 , 8
Toxicology
No toxicity, carcinogenicity, or teratogenicity has been reported.
Botany
The evening primrose is a large, delicate wildflower native to North America, but it is not a true primrose. The blooms usually last only 1 evening. Primrose is a yellow-flowered annual or biennial and can grow from 1 to 3 m in height. The fruit is a dry pod about 5 cm long that contains many small seeds. 5 , 9
Chemistry
Seeds from O. biennis contain 14% of a fixed oil known as evening primrose oil. This oil can contain from 50% to 70% cis-linoleic acid and from 7% to 10% cis-GLA. Wild varieties of O. biennis contain highly variable amounts of linoleic acid and GLA; however, extensive crossbreeding has produced a commercial variety that consistently yields an oil with 72% cis-linoleic acid and 9% GLA. 5 , 9 Also found are cis-6,9,12-octadecatrienoic acid; small amounts of oleic, palmitic, and stearic acids; steroids; campesterol; and beta-sitosterol. Mucilage and tannin in the plant parts have been analyzed. 5
Evening Primrose Oil Uses and Pharmacology
Essential fatty acids are important as cellular structural elements and as precursors of prostaglandins. Essential fatty acids are the biologically active parts of polyunsaturated fats and cannot be manufactured by the body. They must be provided by the diet in relatively large amounts. 5 Recommended intake of linoleic acid and alpha-linolenic acid are 12 g and 1.1 g, respectively, for women 19 to 30 years of age. 10
In theory, the GLA provided by evening primrose oil can be converted directly to the prostaglandin precursor di-homo-gamma-linolenic acid (DGLA) and might be beneficial to people unable to metabolize cis-linoleic acid to GLA or with low dietary intake of cis-linoleic acid. However, this relationship was not proven in a pharmacokinetic study in healthy humans. 11
Premenstrual syndrome/Menopause-associated vasomotor symptomsA number of reviews and randomized clinical trials suggest there is little evidence to support the use of evening primrose oil for menopausal vasomotor symptoms or premenstrual syndrome. 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 A satisfactory meta-analysis of the available data has not yet been achieved, but a protocol has been published by the Cochrane Collaboration, the results of which are pending. 21
The North American Menopause Society does not support the use of evening primrose oil for hot flash relief given the lack of efficacy data. 22
MastalgiaA few researchers suggest benefit from evening primrose oil in the management of cyclic mastalgia, 23 , 24 but there is little evidence to support this. 25 , 26 One randomized, controlled trial found no benefit of evening primrose oil over control. 27
Rheumatoid arthritisA Cochrane review of randomized trials using evening primrose oil versus placebo suggests some benefit in using evening primrose oil for rheumatoid arthritis, despite the relative poor quality of the individual studies. A trend toward reduction of morning stiffness and joint tenderness as well as pain relief has been shown. The authors found the evidence to be sufficient to warrant further larger trials to provide conclusive results and define optimal dosage and duration of therapy. 28 These findings are supported by other reviews, especially with regard to effective duration of therapy. 29 , 30
A more recent randomized, double-blind, placebo-controlled study involving 90 patients with primary Sjorgen syndrome found no statistical significance in patient tiredness with a higher dosage after 6 months of therapy. 31
Other studies, primarily in animals and healthy humans, provide the theoretical rationale for the effect of GLA in inflammatory disease. 32
Multiple sclerosisDespite a seemingly valid theoretical basis for the use of evening primrose oil in multiple sclerosis, there is a lack of evidence to substantiate its use and no new trials since the 1980s. A review of 3 trials suggested an effect with a slower progression of disability and improved relapse (severity and duration) scores, but a randomized, controlled trial, not included in the review, showed no effect. 33 , 34 , 35 , 36 , 37
Atopic dermatitis/Dermatologic disordersA number of reviews and randomized clinical trials suggest a lack of support for the use of evening primrose oil for atopic dermatitis. 19 , 38 , 39 Many of the trials are of poor quality and have apparent issues of bias. 3 , 40
While an earlier review suggested promising results, 41 the most comprehensive meta-analysis to date was unable to establish efficacy. 3 A protocol seeking to assess the effects of oral evening primrose oil and borage oil for treating the symptoms of atopic eczema has been published by the Cochrane Collaboration, the results of which are pending. 42
Other usesCardiovascular disease
There is no recent evidence to support older studies 43 , 44 , 45 suggesting that evening primrose oil reduced platelet aggregation. An observational study suggests serum linoleic acid may protect against ischemic stroke. 46
Despite limited older trials in humans and numerous studies using rats and rabbits, there are no recent randomized, controlled trials demonstrating a beneficial effect of evening primrose oil on cholesterol levels or serum lipids.
A more recent randomized, controlled trial found no effect on endothelial function or vascular tone with evening primrose oil supplementation. 47
Diabetic neuropathyA review of 3 randomized, controlled trials suggested evening primrose oil might improve symptoms of diabetic neuropathy. Dosages in these trials ranged from 360 to 480 mg GLA daily. Few side effects were noted in these trials, and there was no increase in blood glucose levels. 4 , 48
Dyslexia/Brain developmentCurrent interest in the use of evening primrose oil for enhancing intellectual performance in children is yet to be validated by rigorous research.
Studies conducted in children with dyslexia suggest improved reading, spelling, and behavior, 49 , 50 while a Cochrane systematic review and a long-term study (39 months) showed no long-term benefit in infants fed formula supplemented with long-chain polyunsaturated fatty acids. 51 , 52
Eye conditionsStudy results disagree as to the effect of evening primrose oil on dry eye syndrome, 31 , 53 and there is concern regarding high intake of linolenic and linolenic acid and the risk of cataract development. 54 , 55
Dosage
Evening primrose oil has been administered orally in clinical trials at doses between 6 and 8 g/day in adults and 2 and 4 g/day in children. The typical content of GLA in the oil is 8% to 10%. 5
Pregnancy/Lactation
Information regarding safety and efficacy in pregnancy and lactation is lacking. Both linoleic and gamma-linolenic acid are normally present in breast milk, and it is reasonable to assume that evening primrose oil may be taken while breast-feeding.
Interactions
None well documented.
Adverse Reactions
Evening primrose oil is suspected to lower the seizure threshold in epileptic patients. 6 , 7 , 8
Toxicology
Animal toxicological studies and extensive use of evening primrose oil over many years have revealed no data of concern. As a nutritional supplement, the maximum label-recommended daily dose of evening primrose oil is approximately 4 g, containing 300 to 360 mg GLA. There is little concern about the safety of evening primrose oil as a dietary supplement in the recommended dosage range.
Bibliography
1. USDA, NRCS. 2004. The PLANTS Database, Version 3.5 (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA. Accessed September 22, 2005.2. Huntly AL, Ernst E. A systematic review of herbal medicinal products for the treatment of menopausal symptoms. Menopause . 2003;10:465-476.
3. Van Gool CJ, Zeegers MP, Thijs C. Oral essential fatty acid supplementation in atopic dermatitis a meta-analysis of placebo-controlled trials. Br J Dermatol . 2004;150:728-740.
4. Halat KM, Dennehy CE. Botanicals and dietary supplements in diabetic peripheral neuropathy. J Am Board Fam Pract . 2003;16:47-57.
5. Leung A. Encyclopedia of Common Natural Ingredients . 2nd ed. New York, NY: John Wiley; 1996.
6. Werneke U, Earl J, Seydel C, Horn O, Crichton P, Fannon D. Potential health risks of complementary alternative medicines in cancer patients. Br J Cancer . 2004;90:408-413.
7. Ernst E. Ayurvedic medicines. Pharmacoepidemiol Drug Saf . 2002;11:455-456.
8. Vaddadi KS. The use of gamma-linolenic acid and linoleic acid to differentiate between temporal lobe epilepsy and schizophrenia. Prostaglandins Med . 1981;6:375-379.
9. DerMarderosian A, Liberti L. Natural Product Medicine . Philadelphia, PA: George F. Stickley Co.; 1988.
10. Dietary Guidelines for Americans 2005 . U.S. Department of Health and Human Services. U.S. Department of Agriculture. Available from URL: www.healthierus.gov/dietaryguidelines. Accessed October 25, 2005.
11. Martens-Lobenhoffer J, Meyer FP. Pharmacokinetic data of gamma-linoleic acid in healthy volunteers after the administration of evening primrose oil ( Epogram ). Int J Clin Pharmacol Ther . 1998;36;363-366.
12. Chenoy R, Hussain S, Tayob Y, O'Brien PM, Moss MY, Morse PF. Effect of oral gamolenic acid from evening primrose oil on menopausal flushing. BMJ . 1994;308:501-503.
13. Budeiri D, Li Wan Po A, Dornan JC. Is evening primrose oil of value in the treatment of premenstrual syndrome? Control Clin Trials . 1996:17:60-68.
14. Philp HA. Hot flashes - a review of the literature on alternative and complementary approaches. Altern Med Rev . 2003;8:294-302.
15. Kleijnen J. Evening primrose oil: currently used in many conditions with little justification. BMJ . 1994;309:824-825.
16. Fugate SE, Church CO. Nonestrogen treatment modalities for vasomotor symptoms associated with menopause. Ann Pharmacother . 2004;38:1482-1499.
17. Huntly A, Ernst E. A systematic review of herbal medicinal products for the treatment of menopausal symptoms. Menopause . 2003;10:465-476.
18. Kronenberg F, Fugh-Berman A. Complementary and alternative medicine for menopausal symptoms: a review of randomized, controlled trials. Ann Intern Med . 2002;137:805-814.
19. Bendich A. The potential for dietary supplements to reduce premenstrual syndrome (PMS) symptoms. J Am Coll Nutr . 2000;19:3-12.
20. Stevinson C, Ernst E. Complementary/alternative therapies for premenstrual syndrome: a systematic review of randomized controlled trials. Am J Obstet Gynecol . 2001;185:227-235.
21. Strid J, Jepson R, Moore V, Kleijnen J, Iasco SM. Evening primrose oil or other essential fatty acids for the treatment of pre-menstrual syndrome (PMS) (Cochrane Review). In: The Cochrane Library, Issue 1, 2003. Oxford: Update Software.
22. Treatment of menopause-associated vasomotor symptoms: position statement of The North American Menopause Society. Menopause . 2004;11:11-33.
23. Mansel RE. Breastpain. BMJ . 1994;309:866-868.
24. Davies EL, Gateley CA, Miers M, Mansel RE. The long-term course of mastalgia. J R Soc Med . 1998;91:462-464.
25. Goyal A, Mansel RE, Efamast Study Group. A randomized multicenter study of gamolenic acid ( Efamast ) with and without antioxidant vitamins and minerals in the management of mastalgia. Breast J . 2005;11:41-47.
26. Qureshi S, Sultan N. Topical nonsteroidal anti-inflammatory drugs versus oil of evening primrose in the treatment of mastalgia. Surgeon . 2005;3:7-10.
27. 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 . 2002;187:1389-1394.
28. Little CV, Parsons T. Herbal therapy for treating rheumatoid arthritis. Cochrane Database Syst Rev . 2000;(1):CD002947.
29. Darlington LG, Stone TW. Antioxidants and fatty acids in the amelioration of rheumatoid arthritis and related disorders. Br J Nutr . 2001;85:251-269.
30. Belch JJ, Hill A. Evening primrose oil and borage oil in rheumatologic conditions. Am J Clin Nutr . 2000;71(suppl):352S-356S).
31. Theander E, Horrobin DF, Jacobsson LT, Manthorpe R. Gamma-linolenic acid treatment of fatigue associated with primary Sjögren's syndrome. Scand J Rheumatol . 2002;31:729.
32. Calder PC, Yaqoob P, Thies F, Wallace FA, Miles EA. Fatty acids and lymphocyte function. Br J Nutr . 2002;87(supp1):S31-S48.
33. Schwarz S, Leweling H. Multiple sclerosis and nutrition. Mult Scler . 2005:11:24-32.
34. Dworkin RH, Bates D, Millar JH, Paty DW. Linoleic acid and multiple sclerosis: a reanalysis of three double-blind trials. Neurology . 1984;34:1441-1445.
35. McGregor L, Smith AD, Sidey M, Belin J, Zilkha KJ, McGregor JL. Effects of dietary linoelic and gamma linoleic acid on platelet of patients with multiple sclerosis. Acta Neuro Scand . 1989;80:23-27.
36. Horrobin DF. Multiple sclerosis: the rational basis for treatment with colchicine and evening primrose oil. Med Hypothesis . 1979;5:365-378.
37. Namazi MR. The beneficial and detrimental effects of linoleic acid on autoimmune disorders. Autoimmunity . 2004;37:73-75.
38. Ernst E, Pittler MH, Stevinson C. Complementary/alternative medicine in dermatology: evidence-assessed efficacy of two diseases and two treatments. Am J Clin Dermatol . 2002;3:341-348.
39. Hoare C, Li Wan Po A, Williams H. Systematic review of treatments for atopic eczema. Health Technol Assess . 2000;4:1-191.
40. Williams HC. Evening primrose oil for atopic dermatitis. BMJ . 2003;327:1358-1359.
41. Morse PF, Horrobin DF, Manku MS, et al. 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 . 1989;121:75-90.
42. Schmidt K, Pittler MH, Wilson N, van Gool C, Humphreys R, Ernst E. Oral evening primrose oil and borage oil for atopic eczema. The Cochrane Review . In: The Cochrane Library, Issue 1, 2003. Oxford: Update Software.
43. Walker T, Singh PK, Wyatt KM, O'Brien PM. The effect of prostanoid precursors and inhibitors on platelet angiotensin II binding. J Obstet Gynaecol . 1999;19:56-58.
44. Pirich C, Gaszo A, Granegger, Sinzinger H. Effects of fish oil supplementation on platelet survival and ex vivo platelet function in hypercholesterolemic patients. Thromb Res . 1999;96:219-227.
45. Fan Y, Ramos KS, Chapkin RS. Dietary gamma-linoleic acid modulates macrophage-vascular smooth muscle cell interactions. Arterioscler Thromb Vasc Biol . 1995;15:1397-1403.
46. Iso H, Sato S, Umemura U, et al. Linoleic acid, other fatty acids and the risk of stroke. Stroke . 2002;33:2086-2093.
47. Khan F, Elherik K, Bolton-Smith C, et al. The effects of dietary fatty acid supplementation on endothelial function and vascular tone in healthy subjects. Cardiovasc Res . 2003;59:955-962.
48. Ford I, Cotter MA, Cameron NE, Greaves M. The effects of treatment with alpha-lipoic acid or evening primrose oil on vascular hemostatic and lipid risk factors, blood flow, and peripheral nerve conduction in the streptozotocin-diabetic rat. Metabolism . 2001;50:868-875.
49. Richardson AJ, Montgomery P. The Oxford-Durham Study: a randomised, controlled trial of dietary supplementation with fatty acids in children with developmental coordination disorder. Pediatrics . 2005;115:1360-1366.
50. Stordy BJ. Dark adaptation, motor skills, docosahexaenoic acid, and dyslexia. Am J Clin Nutr . 2000;71(suppl):323S-326S.
51. Simmer K, Patole S. Longchain polyunsaturated fatty acid supplementation in preterm infants. Cochrane Database Syst Rev . 2004;(4):CD000376.
52. Auestad N, et al. Visual, cognitive, and language assessments at 39 months; a follow-up study of children fed formulas containing long-chain polyunsaturated fatty acids to 1 year of age. Pediatrics . 2003;112:177-183.
53. Barabino S, Rolando M, Camicione P, et al. Systemic linoleic and gamma-linoleic acid therapy in dry eye syndrome with an inflammatory component. Cornea . 2003;22:97-101.
54. Lu M, Taylor A, Chylack LT, et al. Dietary fat intake and early age-related lens opacities. Am J Clin Nutr . 2005;81:773-779.
55. Seddon JM, Cote J, Rosner B. Progression of age-related macular degeneration. Association with dietary fat, transunsaturated fat, nuts, and fish intake. Arch Ophthalmol . 2003;121:1728-1737.
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Evening Primrose Oil Drug Interactions
Compare Evening Primrose Oil with other medications for the treatment of:
High Cholesterol, Eczema, Heart Disease, Chronic Fatigue Syndrome, Asthma, Sjogren's Syndrome, Premenstrual Dysphoric Disorder, Diabetic Nerve Damage, Rheumatoid Arthritis
