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Evening primrose oil

Evening Primrose Oil  

Natural Standard Monograph, Copyright © 2014 (www.naturalstandard.com). Commercial distribution prohibited. This monograph is intended for informational purposes only, and should not be interpreted as specific medical advice. You should consult with a qualified health care professional before making decisions about therapies and/or health conditions.

Related Terms

  • (+)-catechin, aceite de onagra (Spanish), arachadonic acid (AA), cis-linoleic acid, dihomo-gamma-linolenic acid (DGLA), Echte Nachtkerze (German), ellagic acid, EPO, fever plant, gallic acid, gamma-linolenic acid (GLA), gamolenic acid (GLA), herbe aux anes (French), Huile D'Onagre (French), kaempe natlys, King's Cureall, la belle de nuit (French), linoleic acid (LA), nachtkerzenol (German), night willow-herb, Oenothera biennis L., Oenothera communis Leveill, Oenothera graveolens Gilib, Oenothera paradoxa, omega-6 essential fatty acid, Onagra biennis Scop, Onagraceae (family), Onogra vulgaris, onagre bisannuelle, pentagalloylglucose, penta-O-galloyl-beta-D-glucose, primrose oil, procyanidins, scabish, Spach, stella di sera, sun drop, Teunisbloem (Dutch), unsaturated fatty acids.
  • According to secondary sources, Epogam (40mg GLA and 10mg vitamin E) and Efamast (gamolenic acid) had their product licenses withdrawn October 7, 2002, following a review by the MCA/Committee on Safety of Medicines (CSM) of all the relevant information. It was determined that the information available did not support the standard of efficacy required for the authorization of these products as medicines for the treatment of eczema and mastalgia.
  • Combination product examples: Bronchicum® Tropfen (thyme and primrose), Bronchipret® TP FCT (thyme and primrose), Bronchicum® Elixir S (thyme and primrose).
  • Zestra® (borage seed oil, evening primrose oil, angelica root extract, and coleus extract)
  • The combination compound was called IOVE and was composed of 60mg isoflavones, 440mg primrose oil (consisting of 9-10% gamma linolenic acid (GLA)), and 10mg vitamin E.

Background

  • Native Americans traditionally considered the evening primrose plant's seeds, leaves, and roots to be a food. They also used the plant to treat bruises or wounds, hemorrhoids, stomach problems, and sore throats.
  • Oil extracted from evening primrose (Oenothera biennis) plant seeds consists of a high amount of unsaturated fatty acids. These fatty acids include omega-6 fatty acids, linolenic acid, and gamma-linolenic acid (GLA). GLA has been licensed for treating breast pain and eczema in numerous countries.
  • Evening primrose oil (EPO) has been studied for several disorders, particularly those affected by metabolic products of essential fatty acids. There is good scientific evidence to support EPO for eczema treatment.

Evidence

 

Uses based on scientific evidence 

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare professional.

Grade* 

Atopic dermatitis (eczema) 

Overall, evidence suggests a moderate improvement of eczema with EPO. Large, well-designed studies are needed to provide a definitive conclusion. EPO has been approved for atopic dermatitis and eczema in several countries outside the United States.

B 

Breast cancer 

Early research suggests a beneficial effect of evening primrose oil (EPO) over corn oil in breast tumors. In human research, EPO treatment helped prevent breast cancer recurrence. However, additional studies using EPO alone are needed in this area.

C 

Breast cysts 

Human research is lacking for beneficial effects in EPO use for breast cysts. More well-designed studies are needed before a conclusion may be made.

C 

Breast pain (mastalgia) 

Evening primrose oil (EPO) is licensed for the treatment of mastalgia (breast pain) in the United Kingdom. Conflicting evidence has been reported with EPO in the treatment of breast pain. Additional well-designed studies are needed before a firm conclusion may be made.

C 

Bronchitis 

It is unclear if evening primrose oil (EPO) is an effective treatment for bronchitis. Several studies have evaluated EPO in combination with thyme with some evidence of benefit. Additional well-designed studies using EPO alone are needed.

C 

Cardiovascular health 

Research with EPO has shown a lack of significant beneficial effects on heart function and health. Early research suggests that EPO may decrease blood pressure. Additional research is needed in this area.

C 

Childbirth (labor induction/cervical ripening) 

Historically, EPO has been used to promote easier birth, prevent preterm delivery, induce labor, and ripen the cervix. Low quality studies have revealed that evidence of benefit is lacking. Additional well-designed studies are needed on this topic.

C 

Diabetes 

EPO studies have demonstrated beneficial effects on serum markers in diabetes. Additional studies are required before a conclusion may be made.

C 

Diabetic neuropathy (nerve damage) 

Gamma-linolenic acid (GLA), one of the components of evening primrose oil, may be helpful in people with diabetic neuropathy. Additional studies are needed in this area.

C 

Dry eyes 

Individuals with dry eyes had improved symptoms after supplementation with GLA, a component of EPO. Additional research is needed in this area.

C 

Dyslexia (difficulty reading) 

EPO may benefit people with dyslexia by improving movement skills. However, many studies conducted were low quality or EPO was part of a combination product. Further high quality research evaluating EPO alone is needed.

C 

High cholesterol 

Human research has shown EPO may lower cholesterol and triglycerides. However, there are conflicting reports. Additional studied are needed before a conclusion may be made.

C 

Inflammatory bowel disease (Crohn's disease, ulcerative colitis) 

Evening primrose oil has been studied in people with ulcerative colitis with evidence of benefit. The effects of EPO alone are unclear. Additional research is warranted in this area.

C 

Liver cancer 

Clinical trials have been conducted to assess the effects of EPO on liver cancer with mixed results. Additional studies are required before a conclusion may be made.

C 

Liver disease 

Some research has shown that evening primrose lacks benefit in liver disease symptoms. Other studies suggest that EPO may reduce itching in people with liver disease. Additional, well-designed studies are necessary before a conclusion may be made.

C 

Multiple sclerosis (MS) 

Investigation of linoleic acid (LA) and gamma-linolenic acid (GLA) in the management of MS began in the 1970s. However, evidence is limited regarding EPO for multiple sclerosis. Additional research is needed in this area.

C 

Obesity/weight loss 

Research suggests a lack of evidence for EPO's efficacy in weight-loss and obesity. Additional studies are needed before a conclusion may be made.

C 

Osteoporosis 

Although primrose oil has been suggested as a possible treatment for bone loss and osteoporosis, there is a lack of research involving primrose oil alone. Well-designed research is needed before a firm conclusion may be made.

C 

Postviral/chronic fatigue syndrome 

Studies with high doses of evening primrose oil shoed evidence of benefit in people with chronic fatigue syndrome. However, additional well-designed studies are needed before a conclusion may be made.

C 

Pre-eclampsia/high blood pressure of pregnancy 

Evening primrose oil may have effects on chemicals in the blood called prostaglandins, which may play a role in pre-eclampsia. The combination of EPO and fish oil may be equally as effective as magnesium oxide for pre-eclampsia. Further research in this area is needed.

C 

Raynaud's phenomenon (poor circulation) 

There have been reports of EPO improving symptoms of Raynaud's phenomenon. Well-designed human studies are needed before a conclusion can be made.

C 

Rheumatoid arthritis 

Evening primrose oil for arthritis treatment has conflicting results. GLA may benefit arthritis better than corn oil. More research is needed before a firm conclusion can be made.

C 

Sinus disorders 

An herbal combination product containing primrose has been used in people with sinus inflammation. Additional high quality research in this area is needed.

C 

Scale-like dry skin (ichthyosis vulgaris) 

Early research with evening primrose oil reports a lack of benefit for treating scale-like dry skin. However, additional studies are needed to confirm this conclusion.

C 

Skin conditions (cellulite) 

A combination product containing EPO has had conflicting results for cellulite reduction. Well-designed studies on EPO alone are needed before conclusions can be drawn.

C 

Alcohol intoxication 

Studies have described the effects of individuals receiving EPO after consuming alcohol and in people with alcoholism. However, well-designed studies evaluating EPO alone are lacking. Additional research is warranted before a conclusion may be made.

D 

Asthma 

Research has demonstrated a lack of efficacy for evening primrose oil (EPO) in people with asthma. Further research is needed to confirm this conclusion.

D 

Attention deficit hyperactivity disorder (ADHD) 

Several studies show a lack of benefit from evening primrose oil in treating ADHD. Further research is needed to confirm this conclusion.

D 

Hepatitis B 

In human research, evidence of benefit following GLA (a component of EPO) supplementation was lacking in individuals with hepatitis B. Additional study is needed in this area.

D 

Infant development / neonatal care 

In infants, various effects on fatty acid levels have been described with EPO and fish oil. However, well designed research evaluating EPO alone is still warranted.

D 

Menopause (flushing/bone metabolism) 

Some research reports a lack of evidence that EPO is useful for menopause symptoms, such as flushing and bone mineral density. A combination EPO essential oil and massage may reduce blood pressure. Additional study is needed in this area.

D 

Pre-menstrual syndrome (PMS) 

EPO is widely used internationally by women for symptoms of premenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD). According to some experts, EPO is regarded as an effective treatment for PMS symptoms. However, evidence is conflicting with studies showing a lack of benefit. Additional research is needed in this area.

D 

Psoriasis (skin disorder) 

Initial research lacks a benefit from EPO for psoriasis treatment. Some studies have been done in combination with fish oil, and the effects of EPO alone are unclear. More well-designed trials are needed before a conclusion can be drawn.

D 

Schizophrenia 

Results from most studies do not support EPO use for schizophrenia. Additional well-designed clinical trials are needed.

D 

 

*Key to grades: 

A: Strong scientific evidence for this use;
B: Good scientific evidence for this use;
C: Unclear scientific evidence for this use;
D: Fair scientific evidence against this use (it may not work);
F: Strong scientific evidence against this use (it likely does not work).

For full grading rationale, click here.

Uses based on tradition or theory 

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified health care professional

Acne, acute respiratory distress syndrome (lung condition), anti-aging, antioxidant, bladder disturbances, blood clot prevention, bruises (topical), cancer, cancer prevention, chemical sensitivities (multiple), chemotherapy induced nausea and vomiting, chemotherapy-induced neuropathy (nerve damage), clogged arteries, common cold treatment (symptomatic relief), cystic fibrosis, depression, dry skin, fertility, gastritis (stomach inflammation), gastrointestinal disorders, hangover remedy, headache, hemorrhoids, high blood pressure, inflammation, itching, kidney disease, lupus, mental illness, migraine, pain, postpartum depression, osteoarthritis, scleroderma (skin hardening), Sjogren's syndrome (dry eyes and mouth), skin cancer, skin conditions (in dialysis patients), stomach ulcer, tumors (noncancerous breast tumors/fibroadenomas), urolithiasis (urinary tract stones), vision (acuity), whooping cough, wound healing (poultice).


Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare professional before starting a new therapy. Consult a healthcare professional immediately if you experience side effects.

Allergies

  • Allergy or sensitivity reactions to evening primrose oil (EPO), although rare, have been reported. People who are allergic to EPO, plants in the Onagraceae family, gamma-linolenic acid (GLA), or other ingredients or constituents in EPO should avoid its use.
  • Inflammation on the hands and face has been reported.
  • A healthy pregnant female, who consumed raspberry leaf tea and thirteen 500 milligram EPO capsules, had a ripened cervix and shorter duration of childbirth. After delivery, skin lesions were experienced by the newborn infant, which were resolved by five days after delivery.

Side Effects and Warnings

  • Evening primrose oil is likely safe when taken by mouth in suggested doses for up to one year for premenstrual syndrome (PMS), breast pain, or eczema (atopic dermatitis).
  • Evening primrose oil may cause low blood pressure. Caution is advised in people taking drugs or herbs and supplements that lower blood pressure.
  • Evening primrose oil may increase the risk of bleeding. Caution is advised in people with bleeding disorders or taking drugs that may increase the risk of bleeding. Dosing adjustments may be necessary.
  • Use cautiously in people with seizure disorders or mania. Use cautiously in pregnant or breastfeeding women.
  • Use cautiously in people taking agents for convulsions or depression, agents for the brain, central nervous system (CNS) stimulants, or people undergoing anesthesia.
  • Avoid in people with an allergy or sensitivity reaction to evening primrose oil (EPO). People who are allergic to EPO, plants in the Onagraceae family, gamma-linolenic acid (GLA), or other ingredients or constituents in EPO should avoid its use.
  • Evening primrose oil may also cause abdominal pain, acidity, acne, altered immune system function, anxiety, belching, bloating, cellulitis (skin infection), cervix ripening, colic, constipation, cough, cramping, crying, decreased or increased duration of childbirth, depression, diarrhea, difficulty swallowing, dizziness, dryness of mucous membranes, eczema, fullness, gas, gastrointestinal adverse effects, headache, heartburn, increased bleeding time or decreased platelet aggregation, increased risk of inflammation, indigestion, irregular menstruation, irritability, itchy and fatty skin, loose stools, musculoskeletal adverse effects, nausea, nervous system adverse effects, pneumonia, reproductive system adverse effects, respiratory system adverse effects, seizures or lowered seizure threshold, short temper, skin lesions in newborns, skin rash, slower dilation during childbirth, stomachache, tension, vivid dreams, vomiting, weight gain, or worsening mania.

Pregnancy and Breastfeeding

  • There is a lack of sufficient data on the use of EPO during pregnancy or lactation.
  • A study has reported women taking EPO by mouth to have a longer labor, slower dilation rate, prolonged rupture of membranes, use of oxytocin, and arrest of descent.
  • Females receiving Efamol® for eight months of lactation had increased total fat and essential fatty acids in breast milk. Evidence of adverse effects was lacking in breastfed infants.
  • A healthy pregnant female, who consumed raspberry leaf tea and thirteen 500 milligram EPO capsules, had a ripened cervix and shorter duration of childbirth. After delivery, skin lesions were experienced by the newborn infant, which were resolved by five days after delivery.

Interactions

Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare professional before starting a new therapy.

Interactions with Drugs

  • Evening primrose oil may lower blood sugar levels. Caution is advised when using medications that may also lower blood sugar. People taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.
  • Evening primrose oil may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants ("blood thinners") such as warfarin (Coumadin®) or heparin, anti-platelet drugs such as clopidogrel (Plavix®), and non-steroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).
  • Evening primrose oil may interfere with the way the body processes certain drugs using the liver's "cytochrome P450" enzyme system. As a result, the levels of these drugs may be increased in the blood, and may cause increased effects or potentially serious adverse reactions. People using any medications should check the package insert, and speak with a qualified healthcare professional, including a pharmacist, about possible interactions.
  • Evening primrose oil may increase the amount of drowsiness caused by some drugs. Examples include benzodiazepines such as lorazepam (Ativan®) or diazepam (Valium®), barbiturates such as phenobarbital, narcotics such as codeine, some antidepressants, and alcohol. Caution is advised while driving or operating machinery.
  • Evening primrose oil may cause low blood pressure. Caution is advised in people taking drugs that lower blood pressure.
  • Evening primrose oil may also interact with agents for arthritis, cancer, or obesity; agents for the brain, skin, stomach, or intestines; agents that lower cholesterol; alcohol; aldose reductase inhibitors; anesthetics; antibiotics; anticonvulsants; antidepressant agents such as monoamine oxidase inhibitors (MAOIs) or selective serotonin reuptake inhibitors (SSRIs); anti-inflammatory agents; antipsychotics; antiviral agents; beta-blockers; celecoxib; CNS depressants or stimulants; corticosteroids; COX-2 inhibitors; Faslodex®; phenothiazines; seizure threshold-lowering agents; tamoxifen; or vincristine.

Interactions with Herbs and Dietary Supplements

  • Evening primrose oil may alter blood sugar levels. Caution is advised when using herbs or supplements that may also alter blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.
  • Evening primrose oil may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.
  • Evening primrose oil may interfere with the way the body processes certain herbs or supplements using the liver's "cytochrome P450" enzyme system. As a result, the levels of other herbs or supplements may become too high in the blood. It may also alter the effects that other herbs or supplements possibly have on the P450 system.
  • Evening primrose oil may increase the amount of drowsiness caused by some herbs or supplements.
  • Evening primrose oil may cause altered blood pressure. Caution is advised in people taking herbs or supplements that alter blood pressure.
  • Evening primrose oil may also interact with anesthetics; antibacterials; anticonvulsants; antidepressants such as monoamine oxidase inhibitors (MAOIs) or selective serotonin reuptake inhibitors (SSRIs); anti-inflammatories; antioxidants; antipsychotics; antivirals; CNS depressants or stimulants; COX inhibitors; herbs and supplements for arthritis, cancer, or obesity; herbs and supplements for the brain, skin, stomach, or intestines; herbs and supplements that reduce cholesterol; seizure threshold-lowering herbs and supplements; thyme; vitamin C; zinc.

Authors

Selected References

Natural Standard developed the above evidence-based information based on a systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

  1. Cameron, M., Gagnier, J. J., and Chrubasik, S. Herbal therapy for treating rheumatoid arthritis. Cochrane Database Syst.Rev. 2011;(2):CD002948.
  2. Centre for Reviews and Dissemination. Phyto-anti-inflammatories: a systematic review of randomized, placebo-controlled, double-blind trials (Structured abstract). Database of Abstracts of Reviews of Effects. 2012;(3)
  3. Cronin, H. and Draelos, Z. D. Top 10 botanical ingredients in 2010 anti-aging creams. J Cosmet.Dermatol. 2010;9(3):218-225.
  4. Dante, G. and Facchinetti, F. Herbal treatments for alleviating premenstrual symptoms: a systematic review. J Psychosom.Obstet.Gynaecol. 2011;32(1):42-51.
  5. Darsareh, F., Taavoni, S., Joolaee, S., and Haghani, H. Effect of aromatherapy massage on menopausal symptoms: a randomized placebo-controlled clinical trial. Menopause. 2012;19(9):995-999.
  6. Gupta, H., Pawar, D., Riva, A., Bombardelli, E., and Morazzoni, P. A randomized, double-blind, placebo-controlled trial to evaluate efficacy and tolerability of an optimized botanical combination in the management of patients with primary hypercholesterolemia and mixed dyslipidemia. Phytother.Res 2012;26(2):265-272.
  7. Koo, J. H., Lee, I., Yun, S. K., Kim, H. U., Park, B. H., and Park, J. W. Saponified evening primrose oil reduces melanogenesis in B16 melanoma cells and reduces UV-induced skin pigmentation in humans. Lipids 2010;45(5):401-407.
  8. Platzbecker, U., Aul, C., Ehninger, G., and Giagounidis, A. Reduction of 5-azacitidine induced skin reactions in MDS patients with evening primrose oil. Ann Hematol. 2010;89(4):427-428.
  9. Pruthi, S., Wahner-Roedler, D. L., Torkelson, C. J., Cha, S. S., Thicke, L. S., Hazelton, J. H., and Bauer, B. A. Vitamin E and evening primrose oil for management of cyclical mastalgia: a randomized pilot study. Altern.Med Rev. 2010;15(1):59-67.
  10. Rabahi, M. F., Ferreira, A. A., Madeira, J. G., Galvao, P. M., and Pinto, S. A. Lipoid pneumonia secondary to long-term use of evening primrose oil. J Bras.Pneumol. 2010;36(5):657-661.
  11. Reden, J., El-Hifnawi, D., Zahnert, T., and Hummel, T. The effect of a herbal combination of primrose, gentian root, vervain, elder flowers, and sorrel on olfactory function in patients with a sinonasal olfactory dysfunction. Rhinology 2011;49(3):342-346.
  12. Simmer, K., Patole, S. K., and Rao, S. C. Long-chain polyunsaturated fatty acid supplementation in infants born at term. Cochrane Database Syst.Rev. 2011;(12):CD000376.
  13. Wang, W. Liu P. J. Evening Primrose Oil or other essential fatty acids for the treatment of pre-menstrual syndrome (PMS). Cochrane Database Sys Rev 2010 2010;11:CD001123.
  14. Yakoot, M., Salem, A., and Omar, A. M. Effectiveness of a herbal formula in women with menopausal syndrome. Forsch.Komplementmed. 2011;18(5):264-268.
  15. Zaitone, S. A., Moustafa, Y. M., Mosaad, S. M., and El-Orabi, N. F. Effect of evening primrose oil and omega-3 polyunsaturated fatty acids on the cardiovascular risk of celecoxib in rats. J Cardiovasc.Pharmacol 2011;58(1):72-79.