Evening Primrose Oil


Evening primrose oil is an edible, medicinal oil expelled from the seeds of the common evening primrose. This oil is distinguished because it features in the company of those oils that are rich in a powerful anti-inflammatory compound, called as GLA. Only black currant seed oil and borage oil, besides evening primrose oil, have significant levels of GLA in them. Evening primrose oil is used as a natural remedy to relieve inflammation and pain due to rheumatoid arthritis. It also alleviates the symptoms that accompany premenstrual syndrome (PMS), hot flashes during menopause and the periodic pain in breasts (cyclical mastalgia) experienced by some women of reproductive age. Many of the benefits of evening primrose oil have been confirmed by medical studies, but some are still hotly debated.

With new research coming in, we are seeing that evening primrose oil could play a role in alleviating neurological disorders, like multiple sclerosis. Due to its potent anti-inflammatory role, it is useful in atopic dermatitis and may also be helpful in psoriasis. What is even more interesting is that when it is applied topically, it can improve the elasticity, suppleness and moisturization of skin, making it look and feel younger.

However, it is not entirely free of side effects. Evening primrose oil should be taken with caution as it can be detrimental in pregnancy and for those on blood thinners. We shall discuss its potential side effects in detail.


Evening primrose is very common along the eastern states of United States of America. It can tolerate a wide range of climatic conditions as it grows naturally in New Foundland which is very cold, to the tropical climates of Florida. Its scientific name is Oenothera biennis. It is an herb that can grow to heights of 1.50 meters. It bears yellow flowers and they have a characteristic feature that they spring open in the evenings. That is why the name “Evening” primrose. It is known by other names such as Evening Star, and my favorite, Sun drop.

European settlers reaching the new continent of America noticed that the native tribes were using this herb as a poultice to speed up wound healing. It was transported to Europe where it began to be used for a wide array of inflammatory conditions.

Of great interest to us are its seeds. They are oily and rich in gamma-linolenic acid (GLA). Oil extraction is mechanized. Seeds are first pressed mechanically and then the oil is extracted using the Soxhlet apparatus.Hexane is the solvent medium to leach out its fats. Then it is refined (raffinated) and filled into softgel capsules to be sold as a supplement. And due to refining processes, most of the micronutrients are lost. There is a scarcity of cold pressed evening primrose oil. And these nutrients, found usually in trace amounts, exert antioxidant effects. [1]

Color and Aroma

Evening primrose oil has a mild or faint yellow color. Its aroma has a faint sweet tone. Evening primrose oil is highly susceptible to rancidity. Its polyunsaturated fats get oxidized by the elements of nature (sunlight, heat, oxygen, free radicals). It quickly becomes rancid and then its smell is awful. Moreover, one can get familiar with its aroma only if the product is cold pressed and unrefined. Refined products are often bleached to eliminate natural aroma, and in its place, firms put in natural identical flavoring compounds to make it resemble the natural product.


Evening primrose oil brings about many changes in the body’s functioning. Most of these health benefits are dependent on the anti-inflammatory action of GLA.

  • Anti-inflammation – Oils rich in GLA exert anti-inflammatory action when they are ingested and also when they are applied topically on the skin. This mechanism is the basis for its wide applicability in numerous conditions that are caused by an increase in inflammation. [2],[3]
  • Antioxidant – A medical study has proven that evening primrose oil acts as an antioxidant by boosting the levels of glutathione. This compound is a natural antioxidant found inside our body and which protects the cells of our vital organs, the brain, liver, kidneys and heart from oxidative damage. Eating foods rich in antioxidant capacity keeps us from premature ageing and protects the internal organs from unnatural decay. [4] Its antioxidant effect complements anti-inflammatory effects to keep the skin healthier.
  • Skin Rejuvenation – Evening primrose oil is very rich in linoleic acid, which is structurally very similar to GLA. Linoleic acid is a polyunsaturated fat (PUFA) which is essential for our body. We cannot make it on our own, so we need to eat foods that rich in Linoleic acid. In case we fall deficient of linoleic acid, we suffer from essential fatty acid deficiency (EFAD) disease. In this condition, skin and hair become weak, brittle and undernourished. There is dermatitis and risk of hair fall. Dermatological research clearly indicates the role that linoleic acid plays in protecting the outermost fatty barrier (lipid rich stratum corneum) which safeguards our skin from pathogens and free radicals. This ultra-thin oily covering prevents water inside our skin from evaporating out. In this way, linoleic acid is essential for moisture retention in the skin. [3]
  • Hormone Balance – Evening primrose oil does play a role in alleviating the symptoms of certain conditions specific to women. It has been known to reduce breast pain, premenstrual syndrome and related symptoms which are a result of natural hormonal variations during a woman’s monthly reproductive cycle. It is verifiably useful in alleviating hot flashes. Moreover, it is known to cause cervical ripening and induce early labor. [5], [6], [7]

Health Benefits and Uses

Anti-Ageing Oil

Evening primrose oil is a natural remedy to keep the skin young and taut. Linoleic acid provides structural integrity and conserves moisturization. GLA protects the skin from damage due to chronic inflammation. This type of inflammation may be linked to low sebum production, skin dryness and premature ageing. In a study, healthy adults were put on a regimen of evening primrose oil (EPO) softgel capsules 3 times a day. Each capsule contained 500 mg of EPO. After 12 weeks, the performance of skin was noted. It was found that supplementation with EPO improved moisture levels in the skin by repairing the natural protective outer layer of the skin. This effect is most probably due to linoleic acid in it. Secondly, participants noted that their skin felt smoother. Skin elasticity improved, although only slightly. Maintenance of elasticity of skin is a prerequisite to prevent sagging. Supplementation with EPO (evening primrose oil) brought about increased firmness in the skin. [8]

Evening primrose oil can thus be used as a part of anti-ageing regimen. Apart from this, omega-3 fat rich foods are incredibly healthy for the skin.


Evening primrose oil can help to reduce hormonal acne, particularly in women. It is not clear whether it could be due to the anti-inflammatory effects of GLA in it or because of some modulating effect that it has on hormones. It could be more likely due to anti-inflammatory action because in one study, GLA from borage oil was found to reduce acne lesions. [10] The common denominator seems to be GLA. But it does not help everyone. For some women, it doesn’t help with acne at all. It just provides relief from PMS. In few other women, evening primrose oil even leads to worsening of acne. In this regard, it is similar to biotin. Although most people benefit from biotin supplementation in acne, in some other it leads to severe flare ups.

Atopic Dermatitis (Eczema)

One of the most problematic and stubborn conditions is eczema. It creates multiple, itchy rashes that are so itchy that the affected person may be compelled to scratch them. Skin becomes sensitive and scratching often tears the skin apart. Bodily fluid oozes out and thickens. Since eczema flare ups last many months at a time, it can leave the skin sore and thickened. It usually begins in childhood and continues for life, and till date, no cure has been found. In fact, the underlying mechanisms that lead to this condition have not yet been clearly understood.

Only a few natural substances help to alleviate symptoms of eczema. In some studies, evening primrose oil supplements were found to provide relief to children suffering from it. [9] Similar improvement in condition was also observed when children were made to wear undergarments smeared with borage seed oil (starflower oil). [10] Since both EPO and borage seed oil are rich in GLA, it is speculated that the relief from itching and the extent and appearance of rashes is due to GLA.

Rheumatoid Arthritis

This form of arthritis is auto-immune in nature. Body’s defense mechanism, the immune system, begins attacking our own cells. Although the noticeable manifestations of this condition are tender, swollen, reddish, warm and very painful joints and it becomes more and more painful and debilitating to move the joint. It usually starts to show up in the joints of the fingers and toes. Joint mobility is affected to such an extent that it feels like a disability. However, the condition is not just limited to the decay of joints. In fact, it is so entrenched and systemic that it even starts to degrade the lungs, bone and heart cells. And the biggest problem is that despite all our medical advances, we still haven’t been able to pinpoint the exact mechanisms underlying it, or any certified cure. Almost all treatment is palliative.

Oils rich in gamma linoleic acid (GLA) can provide relief from joint pain, tenderness and redness. In one randomized, double blind study, participants were either given supplements of GLA or cottonseed oil. The cotton seed oil served as placebo as it doesn’t have GLA. After 24 weeks of sustained supplementation with GLA at 1.4 grams per day, it was found that it brought about a reduction in the number of swollen joints, swelling in individual joint and tenderness. [11]

Evening primrose oil curbs the formation of cytokines. These are inflammation flaring chemicals that are surprisingly enough, produced due to the action of our immune system. One of them, the TNF-alpha cytokine is involved in the process of perpetrating rheumatoid arthritis and many such autoimmune conditions. By suppressing its activity, evening primrose oil exerts another mechanism that helps in RA. [14]

In fact, some of the strongest evidences for relief in rheumatoid arthritis have been obtained from GLA. There are also some studies that recommend intake of fatty fish, or its main active constituent, the omega-3 fats (EPA and DHA). Omega-3 does not cure the disease, but it does reduce the need for anti-inflammation medication. [2]

Women’s Health Conditions

Quite possibly the most definitive role of GLA is its beneficial effect on a series of conditions that affect women only.

Although recent studies are inconclusive, one study performed in 1983 recognized the ability of evening primrose oil in alleviating the symptoms of premenstrual syndrome (PMS). It reduced breast pain and tenderness which is linked to the monthly cyclical fluctuations of hormones associated with reproductive and sexual function. Fluid retention in the body is reduced, and along with it, there is relief from bloating. Evening primrose oil also helps to calm irritability and reduce depression that may accompany the period. However, it is not clear whether it can help with cramps that accompany menstrual flow. [12]

This health benefit is attributed to the formation of a powerful anti-inflammatory eicosanoid molecule called Prostaglandin E 1 (PGE1). It opens up constricted blood vessels, especially in the uterus. However, it is this same molecule which is believed to be responsible for inducing of labor and dilation of cervix. Pregnant women should not take evening primrose oil without the prescription or advice of their doctor.

Evening primrose oil can also be taken to relieve hot flashes during menopause. It is one of the few herbal remedies that seem to have a beneficial impact in this condition. Although in most cases, hot flashes and other symptoms of menopause, like night sweats, run on for a year or two. Hormone therapy is usually prescribed for alleviation of symptoms. But a new study recognizes a fact that women have been telling for years. In many women, hot flashes and other distressing symptoms of menopause may go on for as long as 9 to 11 years. Notwithstanding the effectiveness of hormone therapy, long-term use of artificial hormones (over years) aggravates the risk of blood clots, stroke and breast cancer. It becomes essential to find out about non-hormone therapies for mitigating the symptoms. Harvard Health has noted that even some diet and lifestyle modification play an additional role in providing relief. Cutting down on tea and coffee (due to caffeine in them), indulging in meditation and relaxation techniques and practicing mindfulness are some of them. [13]

Diabetic Neuropathy

It refers to a set of nerve related damage and degeneration that is caused by diabetes mellitus. In early stages, it usually begins to affect the nerves of the extremities, causing tingling, burning sensations and pain. Balance is also affected. But this is just the preliminary evidence of diabetic neuropathy. As time passes, the range of nerves that are getting affected rises.

Diabetes is understood to interfere the regulation of blood glucose levels. But it is not common knowledge that it also causes systemic inflammation and subjects the cells of our body to increased levels of free radicals. Since evening primrose oil contains the anti-inflammatory GLA, it was studied for efficacy in diabetic neuropathy. One study involving 111 patients with mild neuropathy noticed that supplementation with 480 mg per day of GLA over the course of 1 year led to a significant reduction in symptoms. [15]

Another study found that a combination therapy using antioxidants and GLA reduced kidney nerve damage in rats in whom diabetes was induced chemically. [16] Now we may hold our suspicions about whether chemically induced diabetes is the same as diabetes mellitus. But antioxidants plus GLA seems like a plausible approach to deal with diabetic neuropathy in humans, and frankly, more in vivo studies should be undertaken based on this premise.

Nutritional and Medicinal Information

The key to an edible oil’s nutritional role is its composition of fatty acids. These fatty acids are natural fats that are mildly acidic.

Fatty acid Carbon notation and type Percentage (by weight)
Linoleic acid (LA) C 18: 2 omega-6 PUFA 73.88
Gamma Linoleic acid (GLA) C 18: 3 omega-6 PUFA 9.24
Oleic acid C 18: 1 omega-9 MUFA 6.93
Palmitic acid C 16: 0 Saturated fat 6.31
Stearic acid C 18: 0 Saturated fat 1.88

Source: 14

We know that major bioactive fats in EPO are linoleic acid and gamma linoleic acid. Oleic acid is a powerful natural moisturizer and pain reliever. It is the dominant fat in olive oil and hazelnut oil. Palmitic and stearic acid are useful saturated fats that help to cleanse the skin off dirt and keep it soft. Palmitic acid helps the skin to keep a well buffered acidity level. Healthy skin should be mildly acidic to counter the pathogens that it encounters all the time.

But an edible oil is not entirely made up of just the fatty acids. When an oily nut or seed is cold pressed, it expresses a wide range of bioactive compounds that are found only in very minute amounts. Despite their minor amounts, they have profound impacts on our health.

Evening primrose oil provides useful amounts of vitamin E. We know from school science that Vitamin E plays a role in preventing neurodegenerative diseases. It reduces the chances of such diseases and conditions like Alzheimer’s, Parkinson’s, Huntington’s, ataxias and age-related neurodegeneration. Vitamin E is also one of the most ubiquitous fat-soluble antioxidant in our body. Alpha tocopherol form of vitamin E protects all our cells from the peroxides that are produced when free radicals attack fats in our body. This mechanism, known as lipid peroxidation, is central to ageing and numerous systemic diseases like the coronary artery disease. We need to take in foods that are rich in antioxidants to keep free radicals under control. The lesser known form of vitamin E, gamma tocopherol, has been found to protect our cells from reactive nitrogen species. These are also a sub-class of free radicals. They are present in the air in cities that have a lot of air pollution from vehicular exhaust, paint and varnish fumes.

Vitamin E sub-type Amount in EPO
Alpha-tocopherol 78 mg per kg
Gamma-tocopherol 187 mg per kg
Delta tocopherol 15 mg per kg


Now we discuss the health benefits of a very special kind of phytonutrients, known as the Polyphenols. It is common knowledge that polyphenols are powerful antioxidants. They are the ones responsible for the especially unique health benefits of berries, fruits, tea, coffee and cocoa. These foods are rich not in vitamins or minerals, but in these phytonutrients. Evening primrose and its oil are also rich in sub-class of Polyphenols known as Phenolic acids.

Phenolic Acid Proven health benefit
Salicylic acid Reduces risk of heart attack and stroke through its platelet inhibitory effect
Vanillic acid Cardioprotective, nephroprotective (protects kidney tissue)
Protocatechuic acid Cardioprotective, boost cognitive function, exerts insulin like effects
Gallic acid Antioxidant, gastroprotective (protects inner lining of stomach), anti-cancer effect by prohibiting metastasis,
Caffeic acid Cardioprotective effect in diabetes, anti-cancer by preventing angiogenesis,
Ferulic acid Anti-diabetes (by protecting beta cells of pancreas), anti-inflammatory, anti-hypertension, neuroprotective (protects spinal cord)

Source:14, 16

The above table lists only the most well-known health benefits of prominent phenolic acids found in evening primrose. These phytonutrients exert a much wider array of therapeutic effect and we have yet to study synergies within them and with other nutrients.

So, we can now appreciate that evening primrose oil is not just the linoleic acid and the gamma linoleic acid. It has so many more bioactive compounds. And frankly, it is the presence of these phytonutrients, in the proportion that they are in EPO, that makes EPO truly unique.

Side Effects, Safe Dosage and Toxicity Issues

Evening primrose oil has some side effects which have been documented and verified by medical research. We should know about them and exercise due caution before deciding to supplement our diet with EPO.

  • Pregnant women should generally avoid using evening primrose oil because the GLA in it has been known to induce labor. It aids in cervical dilation and ripening, which makes it popular with midwives. But in any case, one should discuss with the gynecologist about the suitability of evening primrose oil if it is recommended by midwife.
  • It interferes with platelet aggregation and that is why, it should not be used by those who suffer from bleeding disorders and those who are on blood thinning medication. Evening primrose oil increases the risk of bleeding in people who are taking anti-coagulant drugs or anti-platelet drugs.
  • Evening primrose oil interacts with phenothiazines. These are used for treating or managing depression and mental disorders. Evening primrose oil increases the risk of seizures in people taking this medication. It can even increase the risk of seizures in people suffering from epilepsy. Also, people suffering from schizophrenia should not take EPO. [5]

Suitable dosage of evening primrose oil depends on many factors. As a rule, medical studies estimate dosage of EPO based on the severity of inflammation. Some conditions may be benefitted with a small dosage, like 350 mg per day. In cancer studies, dosages up to 2000 mg per day or even higher are tried. However, there is unanimity of opinion on one matter. EPO should always be taken in the minimal dosage that is just right for a condition. Secondly, if you have been taking omega-3 fats (EPA and DHA), then the body’s need for anti-inflammatory support reduces. As age progresses, our body’s enzymatic activity that naturally converts linoleic acid from edible oil that we use daily, into gamma linoleic acid comes down drastically. Therefore, as we age, we may need to take supplements containing GLA or directly use oils that are rich in it.

Note – Mayo clinic reports that evening primrose oil interferes with absorption of anti-viral drugs used to treat HIV.

Buying and Storage

As with any edible oil, one should make sure to buy from a reputed manufacturer. Evening primrose oil is more likely to be fiddled with. There can be adulterated products on the market. Only firms that use hygienic processing and scientific extraction can deliver a pure product.

It is difficult to source and purchase organic, cold pressed EPO. Much of the products on the market are sold by supplement marketing firms. But if you search more, you would find that some reputed makers of essential oil do produce some EPO as well. They are the few sellers who are selling it in a bottled oil form.

EPO is highly susceptible to rancidity. It contains about 70% linoleic acid which gets oxidized easily. It does not have such high levels of antioxidants to protect it from rancidity for a long period of time. Since it has a short shelf life, it is wise to but it in small volumes only.


  1. The clinical advantages of cold-pressed non-raffinated evening primrose oil over refined preparations. Puri B.K. et al, Med Hypotheses. 2004;62(1):116-8.
  2. Essential fatty acids – Linus Pauling institute at the Oregon State University.
  3. Essential fatty acids and skin health – Linus Pauling institute at the Oregon State University.
  4. Antioxidant potential of evening primrose oil administration in hyperlipemic rabbits. De La Cruz J.P. et al, Life Sci. 1999;65(5):543-55.
  5. Evening primrose – Mayoclinic.
  6. The effect of oral evening primrose oil on menopausal hot flashes: a randomized clinical trial. Farzaneh F. et al, Arch Gynecol Obstet. 2013 Nov;288(5):1075-9
  7. Evening primrose oil and labour, is it effective? A randomised clinical trial. Kalati M. et al, J Obstet Gynaecol. 2018 May;38(4):488-492.
  8. Systemic evening primrose oil improves the biophysical skin parameters of healthy adults. Muggli L., Int J Cosmet Sci. 2005 Aug;27(4):243-9
  9. A long-term study on the use of evening primrose oil (Efamol) in atopic children. Biagi P.L. et al, Drugs Exp Clin Res. 1988;14(4):285-90
  10. Borage oil – OilHealthBenefits.com
  11. Treatment of rheumatoid arthritis with gammalinolenic acid. Leventhal l.J. et al, Ann Intern Med. 1993 Nov 1;119(9):867-73.
  12. The role of essential fatty acids and prostaglandins in the premenstrual syndrome. Horrobin F., J Reprod Med. 1983 Jul;28(7):465-8.
  13. https://www.health.harvard.edu/blog/menopause-related-hot-flashes-night-sweats-can-last-years-201502237745
  14. Evening Primrose (Oenothera biennis) Biological Activity Dependent on Chemical Composition. Magdalena Timoszuk et al, Antioxidants (Basel). 2018 Aug; 7(8): 108.
  15. Treatment of diabetic neuropathy with gamma-linolenic acid. The gamma-Linolenic Acid Multicenter Trial Group. Keen H. et al, Diabetes Care. 1993 Jan;16(1):8-15.
  16. Interaction between oxidative stress and gamma-linolenic acid in impaired neurovascular function of diabetic rats. Cameron N.E. and Cotter M.A. , Am J Physiol. 1996 Sep;271(3 Pt 1):E471-6.
  17. Therapeutic Potential of Dietary Phenolic Acids. Venkata Saibabu et al, Adv Pharmacol Sci. 2015; 2015: 823539.
  18. Effect of dietary supplementation with omega-3 fatty acid and gamma-linolenic acid on acne vulgaris: a randomised, double-blind, controlled trial.  – Jung JY et al, Acta Derm Venereol. 2014 Sep;94(5):521-5

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