Evening Primrose: Health Benefits, Side Effects, Uses, Dose & Precautions

Other Name(s):

Aceite de Onagra, Acide Cis-linoléique, Cis-Linoleic Acid, EPO, Evening Primrose, Evening Primrose Seed Oil, Evening Star, 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 rubricaulis, Oenothera suaveolens, Œnothère, Oil of Evening Primrose, Onagra biennis, Onagraire, Onagre Bisannuelle, Onagre Commune, Primevère du Soir, Primrose, Primrose Oil, Scabish, Scurvish, Sun Drop, Tree Primrose.

Overview

Evening primrose is a plant native to North and South America. It also grows throughout Europe and parts of Asia. It has yellow flowers which open at sunset and close during the day. The oil from the seeds of evening primrose is used to make medicine.

Evening primrose is taken by mouth for skin disorders such as eczema (atopic dermatitis), psoriasis, acne, and dry, itchy, or thickened skin (ichthyosis). It is also used for rheumatoid arthritis, a type of arthritis that affects people with psoriasis, weak bones (osteoporosis), bone loss (osteopenia), Raynaud's syndrome, multiple sclerosis (MS), Sjogren's syndrome, dry eyes, liver cancer, hepatitis B, severe itchy skin due to biliary cirrhosis, high cholesterol, heart disease, a movement disorder in children called dyspraxia, a learning disorder characterized by reading problems (dyslexia), leg pain due to blocked blood vessels (intermittent claudication), alcoholism, a nerve condition usually caused by certain psychiatric drugs (tardive dyskinesia), Alzheimer's disease, and schizophrenia.

Some people take evening primrose by mouth for chronic fatigue syndrome (CFS), asthma, nerve damage related to diabetes, attention deficit-hyperactivity disorder (ADHD), and obesity. Evening primrose is also taken by mouth for stomach and intestinal disorders including ulcerative colitis, irritable bowel syndrome, and peptic ulcer disease.

Women take evening primrose by mouth during pregnancy for preventing high blood pressure (pre-eclampsia), shortening labor, starting labor, and preventing late deliveries. Women also use evening primrose for premenstrual syndrome (PMS), breast pain, and symptoms of menopause such as hot flashes. It is also taken by mouth for endometriosis, a condition in which tissue that normally lines the uterus grows outside the uterus.

Evening primrose is applied to the skin for eczema (atopic dermatitis).

In foods, the oil from evening primrose is used as a source of essential fatty acids.

In manufacturing, the oil from evening primrose is used in soaps and cosmetics.

In Britain, evening primrose used to be approved for treating eczema and breast pain. However, the Medicines Control Agency (MCA), which is the British equivalent of the US Food and Drug Administration (FDA), withdrew the licenses for evening primrose products marketed as prescription drug products for these uses. The licenses were withdrawn because the agency concluded that there is not enough evidence that they are effective. The manufacturer disagreed, but it hasn't published studies yet to prove the effectiveness of evening primrose for these uses.

How does work?

Evening primrose oil contains gamma-linolenic acid which is an omega-6 essential fatty acid. It is involved in regulating inflammation and the immune system.

QUESTION

Next to red peppers, you can get the most vitamin C from ________________. See Answer

Uses

Possibly Ineffective for...

Asthma. Several small studies show that taking 15-20 mL or 4-6 grams of evening primrose daily for up to 16 weeks does not improve asthma symptoms.
Attention deficit-hyperactivity disorder (ADHD). Taking evening primrose, up to 4 grams daily for 4-6 weeks, does not seem to improve ADHD symptoms in children. Taking a specific supplement containing fish oil and evening primrose (Eye Q, Equazen / Novasel) daily for 12 weeks does seem to improve some symptoms in children 7-12 years-old. But it's not clear if this benefit is due to evening primrose or fish oil.
High blood pressure during pregnancy (pre-eclampsia). Early research shows that taking evening primrose during pregnancy does not reduce blood pressure in women with pregnancy-induced high blood pressure or a condition called pre-eclampsia. Taking a combination of evening primrose and fish oil during pregnancy may reduce the risk of tissue swelling (edema). However, the combination also does not reduce the risk of high blood pressure.

Insufficient Evidence to Rate Effectiveness for...

Atopic dermatitis (eczema). Research evaluating evening primrose for eczema shows conflicting results. Some research shows that taking evening primrose, up to 6 grams per day by mouth for 3-5 months, reduces the severity and symptoms of eczema in adults and children. However, other studies show that taking evening primrose, 6-8 grams per day in adults or 2-4 grams per day in children for 12-16 weeks, has no benefit. Other early research shows that applying cream containing evening primrose for 2 weeks may improve symptoms of eczema.
Disorders affecting bile flow in the liver. Early research suggests that taking 2 grams of evening primrose twice daily for 12 weeks improves itchy skin in some people with disorders affecting bile flow in the liver. Improvement seems to take place within 1-2 weeks of starting treatment.
Chronic fatigue syndrome (CFS). One early study shows that taking a specific combination of evening primrose and fish oil (Efamol Marine, Scotia Pharmaceuticals) might reduce CFS-like symptoms that occurred after a viral infection. However, in another study in people with a confirmed diagnosis of CFS, the same product was no better than a placebo (sugar pill).
Nerve damage caused by diabetes. Evidence on the effectiveness of evening primrose for treating nerve damage (neuropathy) in people with diabetes is conflicting. One study shows that taking up to 6 grams of evening primrose daily for up to 12 months improves how well the nerves work in people with nerve damage caused by diabetes. Other research suggests that taking a similar amount of evening primrose does not improve nerve function in people with this condition.
Dry eyes. Early research shows that taking a specific evening primrose product (Qarma, Equazen, London, UK) 3 grams daily for 6 months improves dry eye symptoms in women wearing soft contact lenses.
Dyslexia. An early study shows that taking a combination of evening primrose, tuna oil, and vitamin E (Efalex, Efamol Ltd., UK) for 5 months might improve reading and learning skills in children with dyslexia.
Coordination and movement problems (dyspraxia). One early study shows that taking a combination of evening primrose, fish oil, thyme oil and vitamin E (Efalex, Efamol Ltd., UK) for 4 months might improve motor skills in children with dyspraxia.
Hepatitis B. Early research shows that taking 4 grams per day of evening primrose (Efamol, Scotia Pharmaceuticals, UK) for 12 months does not improve liver damage in people with hepatitis B.
High cholesterol. Some research shows that taking evening primrose can decreases total cholesterol and blood fats called triglycerides while increasing good (HDL) cholesterol. However, in other studies it was ineffective.
Skin disorders characterized by dry, scaly, or thickened skin (ichthyosis). Early research suggests that taking evening primrose, 3 grams per day in adults or 2 grams per day in children, does not improve symptoms of ichthyosis.
Infant development. Some early research shows that adding evening primrose and fish oil to regular infant formula might provide levels of some types of fats that are closer to those in breast milk. In one study, infants fed this formula had better eyesight than infants fed regular formula, but not better than those who were breastfed. It's not clear if this benefit results from evening primrose or fish oil.
Liver cancer. Early research shows that taking 18 grams of evening primrose per day does not affect liver size or survival in people with liver cancer.
Breast pain (mastalgia). Research evaluating evening primrose for breast pain shows conflicting results. Some early research shows that taking up to 4 grams daily for 6-12 months reduces breast pain. However, in other higher quality research, evening primrose is no more effective than a placebo (sugar pill).
Hot flashes and night sweats due to menopause. In most studies, taking evening primrose up to 4 grams daily for up to 6 months does not reduce hot flashes or night sweats any more than a placebo (sugar pill). However, in one study, taking a combination of evening primrose, damiana, ginseng, and royal jelly (Lady 4, Pharco Pharmaceuticals, Egypt) seems to improve how women rated their menopausal symptoms compared to baseline.
Multiple sclerosis (MS). Some early research shows that taking evening primrose for 6 months improves disability scores in some people with MS. However, other research shows that using a specific evening primrose product (Naudicelle, Bio-Oil Research Ltd., Nantwich, Cheshire, UK) for 2 years may increase the likelihood of symptom worsening compared with a placebo (sugar pill).
Obesity. Early research shows that taking 4.8 grams of evening primrose per day for 12 weeks does not add to the weight loss achieved with a reduced calorie diet in obese women.
Low bone mineral density (osteopenia). Research shows that taking a specific product containing evening primrose, calcium, and fish oil (Efacal, Scotia Pharmaceuticals) does not improve bone mineral density compared to just calcium alone in healthy women.
Childbirth (parturition). Research evaluating evening primrose for improving childbirth shows conflicting results. One study shows that taking evening primrose for one week before delivery increases the likelihood that vaginal delivery will be successful. However, other early research shows that taking evening primrose from week 37 of pregnancy until delivery doesn't improve childbirth. In fact, it might prolong labor and increase the need for contraction-inducing medicine (oxytocin).
Common form of psoriasis (plaque psoriasis). Early research shows that taking a combination of evening primrose and fish oil for up to 7 months does not improve long-term plaque psoriasis.
Premenstrual syndrome (PMS). Research evaluating evening primrose for PMS shows conflicting results. Some research shows that taking 4 grams daily for 3 months, or 3 grams daily from day 15 until the end of the menstrual cycle for 4 cycles, improves self-reported symptoms. However, other studies using up to 6 grams daily for up to 4 menstrual cycles found no benefit.
Arthritis in people with psoriasis (psoriatic arthritis). Early research shows that taking a product containing evening primrose and fish oil (Efamol Marine, Scotia Pharmaceuticals, UK) does not improve skin or joint symptoms in people with psoriatic arthritis.
Raynaud's syndrome. Raynaud's syndrome is a condition in which people experience reduced blood flow in response to cold or stress. Early research suggests that taking 6 grams per day of evening primrose (Efamol, Efamol Ltd., UK) for 10 weeks may reduce the occurrence of digital ulcers. However, it does not seem to improve finger temperature or spasm of the blood vessels caused by cold in people with this condition.
Rheumatoid arthritis (RA). One early study suggests that taking 6 grams per day of evening primrose for 12 months improves self-reported symptoms of RA. However, other research has found evening primrose to be no better than a placebo (sugar pill).
Schizophrenia. Research evaluating evening primrose for schizophrenia shows conflicting results. One early study shows that taking 6 grams daily for16 weeks improves scores on a psychological rating scale. However, other research shows that taking 4 grams per day of evening primrose for 2-4 months does not benefit people with long-term, severe schizophrenia.
A disorder in which the glands that produce tears and saliva are damaged (Sjogren's syndrome). Early research suggests that taking evening primrose for 8-10 weeks does not improve dry eye and mouth symptoms in people with Sjogren's syndrome.
A nerve condition caused by long-term use of certain psychiatric drugs (tardive dyskinesia). Early research suggests that taking 6 grams per day of evening primrose for 6-16 weeks does not improve psychiatric drug-induced tardive dyskinesia in schizophrenics.
Ulcerative colitis. Early research shows that taking evening primrose with borage oil improves stool consistency, but not other symptoms of ulcerative colitis.
Alzheimer's disease.
Heart disease.
Other conditions.

More evidence is needed to rate evening primrose for these uses.

Side Effects

Evening primrose is LIKELY SAFE for most people when used in doses up to 6 grams daily for up to a year. When taken by mouth, it can sometimes cause mild side effects including upset stomach, nausea, diarrhea, and headache.

Precautions

Pregnancy and breast-feeding: Taking evening primrose by mouth is POSSIBLY SAFE during pregnancy. Taking up to 4 grams daily for up to 10 weeks during pregnancy seems to be safe. But until this is confirmed by additional research, it is best to stay on the safe side and avoid use, Taking evening primrose during the last weeks of pregnancy might delay labor. Don't use close to the end of pregnancy.

It is POSSIBLY SAFE to take evening primrose oil during breast-feeding, but it's best to check with your healthcare provider first.

Bleeding disorders: There is a concern that evening primrose might increase the chance of bruising and bleeding. Don't use it if you have a bleeding disorder.

Epilepsy or another seizure disorder: There is a concern that taking evening primrose might make seizures more likely in some people.

Schizophrenia: Seizures have been reported in people with schizophrenia treated with phenothiazine drugs, GLA (a chemical found in evening primrose oil), and vitamin E. Get your healthcare provider's opinion before starting evening primrose.

Surgery: Evening primrose might increase the chance of bleeding during or after surgery. Stop using it at least 2 weeks before a scheduled surgery.

Interactions

Lopinavir/Ritonavir (Kaletra)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.

Lopinavir / ritonavir (Kaletra) is changed and broken down by the body. Evening primrose might decrease how quickly the body breaks down lopinavir / ritonavir (Kaletra). Taking evening primrose along with lopinavir / ritonavir (Kaletra) might increase the levels and effects of lopinavir / ritonavir (Kaletra).

Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.

Evening primrose contains GLA (gamma-linolenic acid), which might slow blood clotting. Taking evening primrose along with medications that also slow clotting might increase the chances of bruising and bleeding.

Some medications that slow blood clotting include aspirin, clopidogrel (Plavix), nonsteroidal anti-inflammatory drugs (NSAIDs) such as diclofenac (Voltaren, Cataflam, others), ibuprofen (Advil, Motrin, others), and naproxen (Anaprox, Naprosyn, others), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, warfarin (Coumadin), and others.

Medications used during surgery (Anesthesia)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.

Evening primrose might interact with medications used during surgery. One person who was taking evening primrose and other medications had a seizure during surgery. But there isn't enough information to know if evening primrose or the other medications caused the seizure. Be sure to tell your doctor what natural products you are taking before having surgery. To be on the safe side, you should stop taking evening primrose at least 2 weeks before surgery.

PhenothiazinesInteraction Rating: Moderate Be cautious with this combination.Talk with your health provider.

Taking evening primrose with phenothiazines might increase the risk of having a seizure in some people.

Some phenothiazines include chlorpromazine (Thorazine), fluphenazine (Prolixin), trifluoperazine (Stelazine), thioridazine (Mellaril), and others.

Medications changed by the liver (Cytochrome P450 2C9 (CYP2C9) substrates)Interaction Rating: Minor Be cautious with this combination.Talk with your health provider.

Some medications are changed and broken down by the liver. Evening primrose might decrease how quickly the liver breaks down some medications. Taking evening primrose along with some medications that are changed by the liver might increase the effects and side effects of these medications. Before taking evening primrose, talk to your healthcare provider if you take any medications that are changed by the liver.

Some of these medications that are changed by the liver include celecoxib (Celebrex), diclofenac (Voltaren), fluvastatin (Lescol), glipizide (Glucotrol), ibuprofen (Advil, Motrin), irbesartan (Avapro), losartan (Cozaar), phenytoin (Dilantin), piroxicam (Feldene), tamoxifen (Nolvadex), tolbutamide (Tolinase), torsemide (Demadex), and warfarin (Coumadin).

Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates)Interaction Rating: Minor Be cautious with this combination.Talk with your health provider.

Some medications changed by the liver include lovastatin (Mevacor), clarithromycin (Biaxin), cyclosporine (Neoral, Sandimmune), diltiazem (Cardizem), estrogens, indinavir (Crixivan), triazolam (Halcion), and others.

Dosing

The appropriate dose of evening primrose depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for evening primrose. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.

SLIDESHOW

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Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).

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