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Evening Primrose Oil

Evening primrose oil (EPO) is extracted from the seeds of a North American plant’s flowers.

Pure Medical - Evening primrose

Evening Primrose Oil

Evening primrose oil (EPO) is extracted from the seeds of a North American plant’s flowers.


Evening primrose oil (EPO) is extracted from the seeds of a North American plant’s flowers. Traditionally, the plant has been used to treat:

  • Bruises
  • Haemorrhoids
  • Digestive issues
  • Sore throat

Evening primrose oil is used to treat premenstrual syndrome (PMS), menopause symptoms, arthritis, high cholesterol, acne, and a variety of other conditions, but there is no good scientific evidence to back up these claims.

Its healing properties may be due to the presence of gamma-linolenic acid (GLA). GLA is a type of omega-6 fatty acid that can be found in plant oils.

EPO is typically taken orally or applied topically. Continue reading to learn how EPO may be used to treat a variety of common health issues today.



Evening primrose is a plant that can be found all over Europe and North America.

Evening primrose oil is derived from the seeds of the yellow evening primrose wildflower, Oenothera biennis.

It is high in linoleic acid and gamma-linoleic acid (GLA), both of which are Omega-6 essential fatty acids. Evening primrose oil should not be confused with other plants or oils that contain GLA and omega-6 fatty acids, such as black currant, borage, and flaxseed oil.


Uses & effectiveness

Evening primrose oil serves a variety of purposes.

These are some of them:

  • Menopause symptoms. Anecdotal evidence from menopausal women suggests that using evening primrose oil can alleviate hot flushes. According to one 2013 study, taking EPO for six weeks could reduce the frequency, intensity, and duration of hot flushes. The study’s female participants also reported a significant improvement in their sense of well-being.
  • Pre-menstrual syndrome (PMS). Many women use EPO to treat PMS symptoms like water retention, breast tenderness, and low mood; the Royal College of Obstetricians and Gynecologists reports that it can help with breast tenderness. A 1983 study concluded that taking EPO was ‘highly effective’ in treating PMS symptoms, but more research is required.
  • Dry skin conditions. According to the European Medicines Agency, EPO can be used to relieve itching in both short-term and long-term dry skin conditions, and it is commonly used by eczema patients to help prevent dry, itchy skin. However, a Cochrane Review published in 2013 concluded that evening primrose oil is no more effective than a placebo in treating eczema.
  • Acne. The GLA in evening primrose oil is thought to improve acne by reducing inflammation and scarring, with a Korean study published in 2014 concluding that GLA reduced inflammation in acne sufferers. Before EPO can be recommended as an acne treatment, more research is needed.
  • Arthritis. Rheumatoid arthritis patients frequently use EPO to relieve pain and stiffness. One study found that taking it helped patients with the condition of morning stiffness. According to Versus Arthritis, while the evidence isn’t conclusive, it may ‘assist in the regulation of pain and inflammation.’
  • Osteoporosis. Unsaturated fat consumption has been linked to a lower risk of osteoporosis (bone mineral loss), particularly in postmenopausal women. Because evening primrose oil is almost entirely made up of unsaturated fat, it is thought to help prevent bone loss in osteoporosis patients and the elderly.
  • Bile flow. Taking 2g of evening primrose oil twice a day for 12 weeks improves itchy skin in some people with bile flow disorders in the liver, according to preliminary research. Within 1 to 2 weeks of beginning treatment, signs of improvement begin to emerge.
  • Chronic Fatigue Syndrome (CFS). According to one preliminary study, taking a specific combination of evening primrose and fish oil may potentially reduce CFS-like symptoms that occur after a viral infection. In another study, however, the same product performed no better than a placebo in people with a confirmed diagnosis of CFS (sugar pill).
  • Dry eyes. According to preliminary research, taking a specific evening primrose product – 3g per day for 6 months – improves dry eye symptoms in female contact lens wearers.
  • Cholesterol levels. Evening primrose oil has been shown in some studies to lower total cholesterol and blood fats (triglycerides) while increasing good (HDL) cholesterol. Other studies, on the other hand, have reached the opposite conclusion. As a result, more research is required.
  • Diabetes. Diabetes causes nerve damage. According to research, taking evening primrose oil daily for 6-12 months improves symptoms of diabetic nerve damage.

There is some interest in using evening primrose oil for a variety of other purposes, but there isn’t enough reliable scientific evidence to substantiate whether it’s beneficial.


Side Effects

When taken orally. evening primrose oil is probably safe for most people in doses of up to 6 grammes daily for up to a year. Some people may experience mild side effects such as:

  • Upset stomach
  • Nausea
  • Diarrhoea
  • Headaches
  • Allergic reactions (rare) – seek medical attention immediately if you notice a rash, itching, or breathing difficulties after taking it.

When applied to the skin. There is insufficient reliable information to determine whether evening primrose is safe or what the potential side effects are.

The following are more serious side effects of EPO use:
  • Increased risk of bleeding if used in conjunction with anticoagulant and antiplatelet medication.
  • Seizures are more likely in people who take phenothiazine, a medication used to treat schizophrenia and other psychotic disorders.
  • A decrease in blood pressure – in people who are taking blood pressure medication, EPO may reduce it even more.
  • Seizures can occur if you take it at the same time you are given an anaesthetic.


If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed on this page. In the UK you can also report side effects directly to the Yellow Card Scheme By reporting side effects you can help provide vital information on the safety of this medical supplement.

Is this medicine suitable for you?

Take precautions:

  • Pregnant. Taking evening primrose oil orally may be safe during pregnancy. It appears that taking up to 4 grammes by mouth daily for up to 10 weeks is safe. But, until this is confirmed, proceed with caution. Taking evening primrose oil in the final weeks of pregnancy may cause labour to be delayed. This product should not be used near the end of a pregnancy.
  • Breastfeeding. It is possible that taking evening primrose oil while breastfeeding is safe, but it is best to consult your healthcare provider first.
  • Children. Evening primrose may be safe when taken orally in doses of up to 6 grammes per day. When applied to the skin, it may also be safe.
  • Bleeding disorders. Evening primrose oil may increase the likelihood of bruising and bleeding. If you have a bleeding disorder, avoid using it.
  • Epilepsy or another seizure disorder. In some people, evening primrose may increase the likelihood of seizures.
  • Surgery. Evening primrose may increase the likelihood of bleeding during or after surgery. Stop using it at least two weeks before your surgery.


Consult your doctor

If you are taking any of the following medicines please consult your doctor:

  • Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs) interacts. Evening primrose oil may help to slow blood clotting. Taking evening primrose with other medications that slow blood clotting may increase the risk of bruising and bleeding.
  • Phenothiazines. Evening primrose combined with phenothiazines may increase the risk of seizures in some people.
  • Lopinavir and Ritonavir (Kaletra). Evening primrose may slow the rate at which the body breaks down lopinavir/ritonavir. Taking evening primrose with lopinavir/ritonavir may increase the effects and side effects of the medication.
  • Lithium. Evening primrose may lower lithium levels in the body. Taking evening primrose with lithium may reduce the effects of the lithium.
  • Medications altered by the liver (substrates of Cytochrome P450 2C9 (CYP2C9)). The liver changes and breaks down some medications. Evening primrose may affect how quickly the liver degrades these medications. This could have an impact on the effectiveness and side effects of these medications.



While taking 500mg of evening primrose oil per day is thought to be safe for adults, and even up to 1,300mg per day, it should not be given to children unless advised by a health professional.

Although there is no official ‘upper limit’ for EPO, the European Medicines Agency advises that children under the age of 12 should not take it.

You should also avoid taking EPO if you:

  • Are on blood-thinning drugs like Warfarin. This is due to the fact EPO has blood-thinning effects.
  • Are due to have surgery in two weeks. EPO may cause excessive bleeding if you continue to take it right up until your surgery date.
  • Have epilepsy, schizophrenia or any other seizure disorder. There’s a chance evening primrose oil may increase the risk of seizure.
  • Are pregnant. EPO can cause complications and may increase the risk of miscarriage or induced labour.

Before taking evening primrose oil, consult your healthcare professional and read the label carefully, as dosing instructions vary between products.


Other names

 Aceite de Onagra, Acide Cis-linoléique, Cis-Linoleic Acid, EPO, Evening Primrose, Evening Primrose Seed Oil, Fever Plant, Herbe-aux-ânes, Huile de Graines d’Onagre, Huile D’Onagre, Huile de Primerose, Huile de Primevère Vespérale, Jambon de Jardinier, Jambon du Paysan, King’s Cureall, Mâche Rouge, Night Willow-Herb, Oenothera biennis, Oenothera muricata, Oenothera purpurata, Oenothera rubricaulis, Oenothera suaveolens, Œnothère, Oil of Evening Primrose, Onagra biennis, Onagraire, Onagre Bisannuelle, Onagre Commune, Primevère du Soir, Primrose, Primrose Oil, Scabish, Sun Drop
Evening primrose oil (EPO) is extracted from the seeds of a North American plant’s flowers.