Evening Primrose Oil

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a7_3star Reliable and relatively consistent scientific data showing a substantial health benefit.

a7_2star Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.

a7_1star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.

Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.

For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.

This supplement has been used in connection with the following health conditions:

Used for	Amount	Why
Type 1 Diabetes	4 grams daily	Taking evening primrose oil may help relieve pain from diabetic neuropathy.
Type 1 Diabetes 4 grams daily Supplementing with 4 grams of evening primrose oil per day for six months has been found in double-blind research to improve nerve function and to relieve pain symptoms in people with diabetic nerve damage (neuropathy).¹ Learn More

Used for	Amount	Why
Type 2 Diabetes	4 grams daily	Supplementing with evening primrose oil has been found to improve nerve function and to relieve pain symptoms of diabetic neuropathy.
Type 2 Diabetes 4 grams daily Supplementing with 4 grams of evening primrose oil per day for six months has been found in double-blind research to improve nerve function and to relieve pain symptoms of diabetic neuropathy.² Learn More

Used for	Amount	Why
Eczema	Adults: 500 to 1,000 mg a day of GLA; children: proportionately less, according to body weight	Supplementing with evening primrose oil can supply anti-inflammatory fatty acids that are missing in many people with eczema.
Eczema Adults: 500 to 1,000 mg a day of GLA; children: proportionately less, according to body weight Researchers have reported that people with eczema do not have the normal ability to process fatty acids, which can result in a deficiency of gamma-linolenic acid (GLA).³ GLA is found in evening primrose oil (EPO), borage oil, and black currant seed oil. Some,⁴ ^{, 5} ^{, 6} but not all,⁷ ^{, 8} ^{, 9} ^{, 10} double-blind trials have shown that EPO is useful in the treatment of eczema. An analysis of nine trials reported that the effects for reduced itching were most striking.¹¹ Much of the research uses 12 pills per day; each pill contains 500 mg of EPO, of which 45 mg is GLA. Smaller amounts have been shown to lack efficacy.¹² Learn More

Used for	Amount	Why
Fibrocystic Breast Disease	3 grams daily	Taking evening primrose oil may help alleviate symptoms.
Fibrocystic Breast Disease 3 grams daily In double-blind research, evening primrose oil (EPO) has reduced symptoms of FBD,¹³ ^{, 14} though only slightly.¹⁵ One group of researchers reported that EPO normalizes blood levels of fatty acids in women with FBD.¹⁶ However, even these scientists had difficulty linking the improvement in lab tests with an actual reduction in symptoms. Nonetheless, most reports continue to show at least some reduction in symptoms resulting from EPO supplementation.¹⁷ ^{, 18} Based on this research, many doctors recommend a trial of 3 grams per day of EPO for at least six months to alleviate symptoms of FBD. Learn More

Used for	Amount	Why
Osteoporosis (Fish Oil)	6 grams daily	Fish oil combined with evening primrose oil (EPO) may improve calcium absorption and promote bone formation.
Osteoporosis 6 grams daily A preliminary trial found that elderly women with osteoporosis who were given 4 grams of fish oil per day for four months had improved calcium absorption and evidence of new bone formation.¹⁹ Fish oil combined with evening primrose oil (EPO) may confer added benefits. In a controlled trial, women received 6 grams of a combination of EPO and fish oil, or a matching placebo, plus 600 mg of calcium per day for three years.²⁰ The EPO/fish oil group experienced no spinal bone loss in the first 18 months and a significant 3.1% increase in spinal bone mineral density during the last 18 months. Learn More

Used for	Amount	Why
Premenstrual Syndrome	3 to 4 grams daily	Women with PMS may have impaired conversion of linoleic acid to gamma linolenic acid (GLA). Evening primrose oil contains GLA and may reduce PMS symptoms.
Premenstrual Syndrome 3 to 4 grams daily Women with PMS have been shown to have impaired conversion of linoleic acid (an essential fatty acid) to gamma linolenic acid (GLA).²¹ Because a deficiency of GLA might, in theory, be a factor in PMS and because evening primrose oil (EPO) contains significant amounts of GLA, researchers have studied EPO as a potential way to reduce symptoms of PMS. In several double-blind trials, EPO was found to be beneficial,²² ^{, 23} ^{, 24} ^{, 25} whereas in other trials it was no more effective than placebo.²⁶ ^{, 27} Despite these conflicting results, some doctors consider EPO to be worth a try; the amount usually recommended is 3–4 grams per day. EPO may work best when used over several menstrual cycles and may be more helpful in women with PMS who also experience breast tenderness or fibrocystic breast disease.²⁸ Learn More

Used for	Amount	Why
Rheumatoid Arthritis	540 to 1,100 mg daily of GLA	Evening primrose oil appears to be an effective treatment for people with rheumatoid arthritis. It contains gamma linolenic acid, which is converted in part to an anti-inflammatory substance.
Rheumatoid Arthritis 540 to 1,100 mg daily of GLA Oils containing the omega-6 fatty acid gamma linolenic acid (GLA)—borage oil,²⁹ ^{, 30} ^{, 31} black currant seed oil,³² and evening primrose oil (EPO)³³ ^{, 34}—have been reported to be effective in the treatment for people with RA. Although the best effects have been reported with use of borage oil, that may be because more GLA was used in borage oil trials (1.1–2.8 grams per day) compared with trials using black currant seed oil or EPO. The results with EPO have been mixed and confusing, possibly because the placebo used in those trials (olive oil) may have anti-inflammatory activity. In a double-blind trial, positive results were seen when EPO was used in combination with fish oil.³⁵ GLA appears to be effective because it is converted in part to prostaglandin E1, a hormone-like substance known to have anti-inflammatory activity. Learn More

Used for	Amount	Why
Skin Ulcers	1,500 mg with each meal	A preliminary report suggested that evening primrose oil improves blood flow to the legs and heals or reduces the size of venous leg ulcers.
Skin Ulcers 1,500 mg with each meal A preliminary report suggested that evening primrose oil improves blood flow to the legs and heals or reduces the size of venous leg ulcers.³⁶ No controlled research has further investigated this claim. Learn More

Used for	Amount	Why
Alcohol Withdrawal	Refer to label instructions	In a double-blind study of alcoholics in a detox program, supplementing with EPO led to greater improvement than did placebo in some parameters of liver function.
Alcohol Withdrawal Alcoholics may be deficient in a substance called prostaglandin E1 (PGE1) and in gamma-linolenic acid (GLA), a precursor to PGE1.³⁷ In a double-blind study of alcoholics who were in a detoxification program, supplementation with 4 grams per day of evening primrose oil (containing 360 mg of GLA) led to greater improvement than did placebo in some, but not all, parameters of liver function.³⁸ Learn More

Used for	Amount	Why
Atherosclerosis	Refer to label instructions	Taking evening primrose oil has been shown to lower cholesterol in double-blind research. Lowering cholesterol levels should in turn reduce the risk of atherosclerosis.
Atherosclerosis Though low levels (2 grams per day) of evening primrose oil appear to be without action,³⁹ 3–4 grams per day have lowered cholesterol in double-blind research.⁴⁰ Lowering cholesterol levels should in turn reduce the risk of atherosclerosis. Preliminary research shows that chondroitin sulfate may prevent atherosclerosis in animals and humans and may also prevent heart attacks in people who already have atherosclerosis.⁴¹ ^{, 42} However, further research is needed to determine the value of chondroitin sulfate supplements for preventing or treating atherosclerosis. Learn More

Used for	Amount	Why
Attention Deficit–Hyperactivity Disorder	Refer to label instructions	A deficiency of several essential fatty acids has been observed in some children with ADHD. In one study, children who received evening primrose oil showed minor improvements.
Attention Deficit–Hyperactivity Disorder A deficiency of several essential fatty acids has been observed in some children with ADHD compared with unaffected children.⁴³ ^{, 44} One study gave children with ADHD evening primrose oil supplements in an attempt to correct the problem.⁴⁵ Although a degree of benefit was seen, results were not pronounced. In a 12-week double-blind study, children with ADHD were given either a placebo or a fatty-acid supplement providing daily: 186 mg of eicosapentaenoic acid (EPA), 480 mg of docosahexaenoic acid (DHA), 96 mg of gamma-linolenic acid (GLA), 864 mg of linoleic acid, and 42 mg of arachidonic acid. Compared with the placebo, the fatty-acid supplement produced significant improvements in both cognitive function and behavioral problems.⁴⁶ No adverse effects were seen. In a preliminary trial, supplementation with approximately 400 mg of flaxseed oil and 25 mg of vitamin C, each twice a day for three months, was associated with an improvement of symptoms in children with ADHD.⁴⁷ Learn More

Used for	Amount	Why
Chronic Obstructive Pulmonary Disease	Refer to label instructions	Evening primrose oil contains gamma-linolenic acid, a type of omega-3 fatty acid that has been linked to reduced risk of COPD.
Chronic Obstructive Pulmonary Disease A greater intake of the omega-3 fatty acids found in fish oils has been linked to reduced risk of COPD,⁴⁸ though research has yet to investigate whether fish oil supplements would help people with COPD. In a double-blind trial, people with COPD received a fatty acid supplement (providing daily 760 mg of GLA [gamma-linolenic acid], 1,200 mg of ALA [alpha-linolenic acid], 700 mg of EPA [eicosapentaenoic acid], and 340 mg of DHA [docosahexaenoic acid]) or a placebo (80% palm oil and 20% sunflower oil) during an eight-week rehabilitation program. Compared with the placebo, the fatty acid supplement significantly improved exercise capacity.⁴⁹ While two of the fatty acids supplied in this supplement (EPA and DHA acid) are found in fish oil, it is not known which components of the supplement were most responsible for the improvement. Gamma-linolenic acid is found in evening primrose oil, black currant seed oil, and borage oil; alpha-linolenic acid is found in flaxseed oil and other oils. Learn More

Used for	Amount	Why
Intermittent Claudication	Refer to label instructions	In a preliminary trial, supplementing with evening primrose oil led to a 10% increase in exercise tolerance in people with intermittent claudication.
Intermittent Claudication Caution: One study showed a slightly increased risk of vascular surgery among people with intermittent claudication who took beta-carotene supplements.⁵⁰ Until more is known, people with intermittent claudication wishing to use beta-carotene supplements should first consult with their doctor. Learn More

Used for	Amount	Why
Irritable Bowel Syndrome and PMS	Refer to label instructions	In one trial, women with IBS who experienced worsening symptoms before and during their menstrual period were helped by taking evening primrose oil.
Irritable Bowel Syndrome and PMS In one trial, women with IBS who experienced worsening symptoms before and during their menstrual period were helped by taking enough evening primrose oil (EPO) to provide 360–400 mg of gamma linolenic acid (GLA) per day.⁵¹ In that trial more than half reported improvement with EPO, but none was helped in the placebo group. The effects of EPO in other groups of IBS sufferers have not been explored.

Used for	Amount	Why
Multiple Sclerosis	Refer to label instructions	The omega-6 fatty acids found in such oils as evening primrose oil (EPO) may be beneficial. When people with MS were given EPO, their hand grip improved in one study.
Multiple Sclerosis The omega-6 fatty acids, found in such oils as evening primrose oil (EPO) and sunflower seed oil, also may be beneficial. When people with MS were given 4 grams of EPO for three weeks, their hand grip improved.⁵² In a review of three double-blind trials, two of the trials reported that linoleic acid reduced the severity and length of relapses.⁵³ When the data were re-examined, it was found that taking linoleic acid decreased disability due to MS in all three trials. According to these researchers, taking linoleic acid while following a diet low in animal fat and high in polyunsaturated fat may be even more beneficial. Amounts used in these trials were approximately 17 to 23 grams of linoleic acid per day, provided by 26 to 35 grams of sunflower seed oil. Learn More

Used for	Amount	Why
Raynaud’s Disease	Refer to label instructions	Fatty acids in evening primrose oil (EPO) inhibit the formation of prostaglandins, which promote blood vessel constriction. One study found that supplementing with EPO reduced the number and severity of attacks.
Raynaud’s Disease Fatty acids in evening primrose oil (EPO) inhibit the formation of biochemical messengers (prostaglandins) that promote blood vessel constriction. A double-blind trial of 21 people with Raynaud’s disease found that, compared with placebo, supplementation with EPO reduced the number and severity of attacks despite the fact that blood flow did not appear to increase.⁵⁴ Researchers have used 3,000–6,000 mg of EPO per day. Learn More

Used for	Amount	Why
Tardive Dyskinesia	Refer to label instructions	Several people have experienced improvement while taking evening primrose oil.
Tardive Dyskinesia Several people have experienced an improvement in TD while taking evening primrose oil (EPO).⁵⁵ In a double-blind study, however, supplementing with EPO (12 capsules per day) resulted only in a minor, clinically insignificant improvement.⁵⁶ Learn More

Also indexed as:

botanicals,
evening primrose oil,
herbal dietary supplements,
herbal medicine,
herbal remedies,
herbal therapy,
herbalism,
plant Medicine,
primrose oil

About this treatment

How to Use It

Although many people may have inadequate levels of GLA, the optimal intake for this nutrient remains unknown. Researchers often use 3,000–6,000 mg of EPO per day, which provides approximately 270–540 mg of GLA.

Where to Find It

EPO is found primarily in supplements. Its presumed active ingredient, GLA, can also be found in black currant seed oil and borage oil supplements. However, it is not known whether the effects of these three oils in the body are the same.

Possible Deficiencies

Those with premenstrual syndrome,diabetes, scleroderma, Sjogren’s syndrome,tardive dyskinesia,eczema, and other skin conditions can have a metabolic block that interferes with the body’s ability to make GLA. In preliminary research, supplementation with EPO has helped people with these conditions.

There is evidence that alcoholics may be deficient in GLA, and a double-blind study suggested that alcohol withdrawal may be facilitated with EPO supplementation. Many people in Western societies may be at least partially GLA-deficient as a result of aging, glucose intolerance, high dietary fat intake, and other problems. People with deficiencies would presumably benefit from supplemental GLA intake from EPO, black currant seed oil, or borage oil.

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Last Review: 05-11-2011

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The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2011.

© 1995-2011 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated. This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.

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