Evening primrose: benefits, dosage, contraindications
Scientific name(s)
Oenothera biennis
Family or group:
Plants
Active ingredients:
Gamma-linolenic acid
Linoleic acid
Indications
Scoring methodology
EFSA approval.
Rheumatoid arthritis ✪✪✪✪✪
Two small clinical studies show that taking 6 grams of evening primrose oil per day for 12 months improves subjective symptoms, but not objective symptoms of rheumatoid arthritis, compared with placebo. nnEvening primrose oil has also been evaluated in combination with other ingredients. A preliminary clinical trial shows that taking evening primrose oil at 2.6 grams per day together with a fish oil product at 2 grams per day for 12 weeks modestly reduces total symptom score, pain intensity, and the number of painful joints compared with placebo, but not compared with taking the same fish oil product at 5 grams per day without evening primrose oil, which suggests a role for the evening primrose oil.nn
Posologie
By mouth: seed
2.6 - 6 g
oil
Synergies
Evening primrose oil in patients with rheumatoid arthritis and the side effects of nonsteroidal anti-inflammatory drugs
Effects of altering dietary essential fatty acids on requirements for nonsteroidal anti-inflammatory drugs in patients with rheumatoid arthritis: a double-blind, placebo-controlled study
Treatment of rheumatoid arthritis with prostaglandin E1 precursors cis-linoleic acid and gamma-linolenic acid
Clinical Benefits of n-3 PUFA and γ-Linolenic Acid in Patients with Rheumatoid Arthritis
Diabetic neuropathy ✪✪✪✪✪
Clinical research shows that taking evening primrose oil providing 360 to 480 mg of gamma-linolenic acid (GLA) per day for 6 to 12 months improves measures of nerve conduction velocity, amplitudes of muscle and nerve action potentials, reflexes, and temperature sensation in patients with mild diabetic neuropathy. Improvements were significantly greater in patients with better-controlled diabetes. The glycated hemoglobin (HbA1C) level was not significantly different between treatment groups, indicating that GLA had no effect on glycemic control. The results of another trial examined the vibratory perception threshold, a measure different from those used in previous trials. This randomized, double-blind, placebo-controlled study examined 51 patients with type 1 and type 2 diabetes and autonomic peripheral neuropathy who received 480 mg of GLA per day or placebo for 1 year. At the end of the study, patients receiving evening primrose oil showed no improvement in vibratory perception threshold compared with placebo.
Posologie
Oral: seed
3 g
12 months
oil
Purewal TS, Evans PMS, Havard F, O’Hare JP. Lack of effect of evening primrose oil on autonomic function tests after 12 months of treatment. Diabetologia
Botanicals and Dietary Supplements in Diabetic Peripheral Neuropathy
Treatment of diabetic neuropathy with gamma-linolenic acid. The gamma-Linolenic Acid Multicenter Trial Group
Eczema ✪✪✪✪✪
In studies conducted in adults, taking 2 to 3 grams of evening primrose oil orally twice a day for 3 weeks to 5 months appears to reduce the extent of atopic dermatitis and symptoms of itching and dryness.nnIn children up to 18 years of age, a few small clinical trials show that taking evening primrose oil orally at age-dependent doses of 0.5 to 6 grams per day for 2 weeks to 5 months reduces the extent and severity of atopic dermatitis and improves symptoms such as itching, dryness, and pruritus compared with placebo.nnHowever, in other studies, evening primrose oil at 2 to 8 grams per day in 1 to 2 divided doses for 12 to 16 weeks did not improve atopic dermatitis compared with baseline or placebo.nnThe conflicting results may be due to differences in baseline severity of atopic dermatitis, time since diagnosis, or the dose of evening primrose oil used.
Posologie
Oral: seed
2 - 3 g
oil
A long-term study on the use of evening primrose oil (Efamol) in atopic children
Oral evening primrose oil and borage oil for eczema
Evening primrose oil is effective in atopic dermatitis: a randomized placebo-controlled trial
Evening primrose oil is effective in atopic dermatitis: a randomized placebo-controlled trial
Evening primrose oil (Efamol) in the treatment of children with atopic eczema
Atopic dermatitis and essential fatty acids: a biochemical basis for atopy?
Evening primrose oil in the treatment of atopic eczema: effect on clinical status, plasma phospholipid fatty acids and circulating blood prostaglandins
Treatment of atopic eczema with evening primrose oil
Oral evening-primrose-seed oil improves atopic eczema
The therapeutic effect of evening primrose oil in atopic dermatitis patients with dry scaly skin lesions is associated with the normalization of serum gamma-interferon levels
Treatment of atopic eczema with evening primrose oil
Premenstrual syndrome ✪✪✪✪✪
A low level of prostaglandin E1 (PGE1), resulting from a deficiency in essential fatty acids, causes increased sensitivity to prolactin, which occurs at ovulation and rises during the luteal phases. Linoleic acid, as an essential precursor in the synthesis of PGE1, promotes their synthesis and alleviates premenstrual syndrome (PMS). The therapeutic potential of evening primrose oil in the management of PMS has been the subject of numerous clinical trials. Two small clinical studies show that oral intake of 3 to 4 grams per day for 3 months, from day 15 to the end of the menstrual cycle for 4 cycles, improves the subjective symptoms of PMS compared with placebo. In another randomized, double-blind, placebo-controlled trial, the soothing effect of 180 mg of gamma-linolenic acid was compared with placebo on the clinical symptoms of 28 women with PMS across three luteal phases. Irritable bowel syndrome was the most common symptom among women with PMS, followed by breast swelling, drowsiness, and skin rash. After treatment, patients in the gamma-linolenic acid group showed higher levels of gamma-linolenic acid and dihomo-gamma-linolenic acid in plasma phospholipids compared with the placebo group. Severity and duration of PMS (physical, mental, and social aspects), and irritability improved in the gamma-linolenic acid group compared with the placebo group. However, other clinical research shows that taking 3 to 6 grams of evening primrose oil per day for 2 to 4 menstrual cycles is not beneficial compared with placebo.
Posologie
Oral: seed
3 - 4 g
oil
Efficacy of γ-linolenic Acid for Treatment of Premenstrual Syndrome, as Assessed by a Prospective Daily Rating System
Biochemical and clinical effects of treating the premenstrual syndrome with prostaglandin synthesis precursors
Evening primrose oil and treatment of premenstrual syndrome
Evening Primrose (Oenothera biennis) Oil in Management of Female Ailments
A double‐blind trial of evening primrose oil in the premenstrual syndrome: Nervous symptom subgroup
Mastalgia ✪✪✪✪✪
Although some low-quality clinical studies have suggested that taking 1 to 4 grams of evening primrose oil per day for 3 to 6 months may reduce breast pain, higher-quality clinical research shows that taking 3 to 4 grams of evening primrose oil in 2 to 3 divided doses per day for 6 to 12 months reduces breast pain only compared with baseline, but not compared with placebo. nnAn observational study found that taking evening primrose oil 1300 mg twice daily for 6 weeks reduced pain associated with mastalgia compared with acetaminophen 500 mg twice daily.nn
Posologie
Oral: seed
1 - 4 g
oil
Mastalgia: a 3 year Australian study
DANAZOL VERSUS OIL OF EVENING PRIMROSE IN THE TREATMENT OF MASTALGIA
Mastalgia cured! Randomized trial comparing centchroman to evening primrose oil
Evening Primrose (Oenothera biennis) Oil in Management of Female Ailments
A Systematic Review and Meta-Analysis of the Efficacy of Evening Primrose Oil for Mastalgia Treatment
Menopause ✪✪✪✪✪
Taking evening primrose oil at a dose of 1 gram per day for 8 weeks reduces psychological symptoms, such as depressed mood, irritability and anxiety, by about 45% compared with baseline. These changes were statistically significant compared with placebo. Evening primrose oil has also been evaluated in combination with other ingredients. A clinical trial shows that taking one capsule per day of a combination of evening primrose oil with soy isoflavones, black cohosh and chaste tree for 12 weeks moderately reduces the severity of hot flashes, sweating, sleep problems, depressed mood and irritability compared with placebo. No effect was observed on plasma lipids, joint discomfort, cardiac discomfort, anxiety, fatigue or sexual problems. Another preliminary clinical trial shows that taking a combined product providing 440–880 mg of evening primrose oil per day with isoflavones and vitamin E for 6 months results in a 57% to 63% reduction in subjective menopausal symptoms compared with baseline.
Posologie
Oral: seed
1 g
oil
Synergies
Efficacy and Safety of Nutraceutical on Menopausal Symptoms in Post-Menopausal Women: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial
Effect of a compound containing isoflavones, primrose oil and vitamin E in two different doses on climacteric symptoms
The effect of oral evening primrose oil on menopausal hot flashes: a randomized clinical trial
Evening Primrose (Oenothera biennis) Oil in Management of Female Ailments
Multiple sclerosis ✪✪✪✪✪
Preliminary clinical research in adults with MS shows that taking a combination of evening primrose oil 0.6–0.7 gram and hemp oil (5.4 g–6.3 g) three times a day for 6 months reduces disability scores and relapse rate compared with baseline.nnEvening primrose oil is a rich source of omega-6 gamma-linolenic acid (GLA), which is a precursor of eicosanoids, constituents of cell membranes. The biochemical pathway of dietary gamma-linolenic acid (GLA) metabolism ultimately leads to prostaglandin E1 (PGE1), which has powerful anti-inflammatory activity and is often recommended for inflammatory and autoimmune conditions.nnIf there is a partial deficiency of GLA in MS, one might expect reduced formation of PGE1 and perhaps increased synthesis of PGE2. The deficit in PGE1 would result in defective T-lymphocyte function with increased susceptibility to infections and autoimmune damage. It is known that lymphocytes from patients with MS behave abnormally in various tests and there is clear evidence of a particular defect of suppressor T lymphocytes, one function of which is to modulate B-lymphocyte responses.nnCorrection of the PGE1 deficiency should tend to restore normal immunological function.nn
Posologie
Oral: seed
1.8 - 2.1 g
oil
Synergies
Multiple sclerosis: the rational basis for treatment with colchicine and evening primrose oil
The effect of evening primrose oil on fatigue and quality of life in patients with multiple sclerosis
Dry skin ✪✪✪✪✪
The EMA states that evening primrose oil is traditionally used for the symptomatic relief of itching in acute and chronic dry skin conditions.
Posologie
Topical, oral: seed
4 - 6 g
oil
Itching ✪✪✪✪✪
The EMA states that evening primrose oil is traditionally used for the symptomatic relief of itching in acute and chronic dry skin conditions.
Posologie
Topical: seed
4 - 6 g
oil
Wrinkles ✪✪✪✪✪
Evening primrose oil is traditionally used externally for its soothing properties on skin eruptions, dermatoses, or skin aging. When taken internally, it is used to combat loss of epidermal elasticity and skin dryness.
Posologie
Oral: seed, buds
alcoholic extract, oil
Effect of the Oral Administration of Common Evening Primrose Sprout (Oenothera biennis L.) Extract on Skin Function Improvement in UVB-irradiated Hairless Mice
Properties
Anti-inflammatory
Gamma-linolenic acid (GLA) is the main constituent of evening primrose responsible for its anti-inflammatory effects. It reduces the production of interleukin-1 beta (IL-1β), which can be involved in inflammatory diseases such as rheumatoid arthritis. GLA is metabolized into dihomo-gamma-linolenic acid (DGLA), a precursor of prostaglandin E1, which inhibits inflammatory polymorphonuclear leukocytes. GLA may also competitively inhibit the synthesis of series-2 pro-inflammatory prostaglandins. DGLA is converted into 15-hydroxy-DGLA, which blocks the conversion of arachidonic acid into inflammatory leukotrienes. GLA and DGLA appear to improve the balance between inflammatory and non-inflammatory prostaglandins and leukotrienes.
Usages associés
Antiplatelet agents/Anticoagulant
Evening primrose oil may decrease platelet aggregation and prolong bleeding time. In vitro research results suggest that this may be due to the component dihomo-gamma-linolenic acid (DGLA).
Dermatologic effect
Evening primrose oil has a high content of linoleic acid and gamma-linolenic acid; it strengthens the epidermal barrier, normalizes excessive transepidermal water loss, regenerates the skin, and improves smoothness after topical and oral applications. It also shows a notable moisturizing effect in patients with acne treated with isotretinoin. Additionally, its high gamma-linolenic acid content provides anti-inflammatory eicosanoids that prevent epidermal hyperproliferation through their antiproliferative properties.
Usages associés
Cardiovascular
Evening primrose oil, rich in gamma-linolenic acid (GLA), appears to help reduce triglyceride levels. This reduction could result from two mechanisms: on the one hand, inhibition of triglyceride production in the liver, and on the other hand, activation of enzymes that break these triglycerides down into free fatty acids.nnIn addition, evening primrose oil may improve HDL cholesterol levels, which is beneficial for cardiovascular health and could help prevent complications such as atherosclerosis and coronary heart disease.nn
Safe dosage
Adults aged 12 years and over: 2 g - 6 g
Single dose: 2-3 g Daily dose: 4-6 g. Evening primrose has been used safely at doses up to 6 grams per day for one year.
Children aged 5 to 12 years: 2 g - 3 g
In children up to 5 years of age, doses of evening primrose oil up to 3 grams per day have been used safely for 5 months, and 0.5 gram/kg per day has been used safely for 8 weeks. In children up to 12 years of age, doses of 4 to 6 grams per day have been used safely for 3 to 5 months. In children aged 2 to 10 years, evening primrose oil was applied to the affected skin areas twice daily for a maximum of 3 months.
Interactions
Médicaments
Phenothiazines: moderate interaction
In a placebo-controlled study, 8 patients received EFAMOL capsules (evening primrose oil providing 329 mg linoleic acid and 58 mg gamma-linolenic acid + Vitamin E 7.5 IU) in addition to their usual treatment (phenothiazines for schizophrenia), of whom 3 patients developed epileptic seizures. In another study, 3 long-standing schizophrenic patients taking evening primrose oil were hospitalized for worsening of their schizophrenia and their EEG showed temporal lobe epilepsy. In contrast, no epileptiform convulsions or other events were reported in a crossover study of 48 patients taking phenothiazines with evening primrose oil for 4 months. Evening primrose oil could possibly increase the well-recognized epileptogenic effects of phenothiazines.
Ritonavir: moderate interaction
In a case report, an HIV-positive patient who was taking evening primrose oil (Efamol) at the same time as lopinavir/ritonavir experienced serum lopinavir levels rising to as high as 15.2 mg/L. Six weeks after stopping the evening primrose oil, lopinavir levels returned to the normal range of 5 to 10 mg/L. When the patient resumed evening primrose oil for one week, his lopinavir level rose from 6.69 to 8.11 mg/L. It is suspected that evening primrose oil increases lopinavir levels by inhibiting cytochrome P450 3A4 (CYP3A4), which metabolizes lopinavir. However, this effect has not been reported in other studies.
Lopinavir: moderate interaction
A 47-year-old HIV-positive man taking: Lopinavir boosted with Ritonavir 533/133 mg twice daily, Tenofovir 245 mg/day and Lamivudine 150 mg twice daily. He developed persistent diarrhea (diarrheal episodes occurring more than 5 times/day) and a high Lopinavir level of 15.2 mg/L (a 56% increase) after consuming evening primrose oil and a supplement containing Aloe, Rhubarb, Licorice and Peppermint. The Lopinavir level returned to normal (5 to 10 mg/L) 6 weeks after stopping all herbal preparations. The patient re-used evening primrose oil for 1 week and the Lopinavir level rose from 6.69 mg/L to 8.11 mg/L, with no adverse effects reported.
Lithium: weak interaction
In a case report, a patient receiving a stable dose of lithium for 10 years experienced a reduction in lithium levels after taking 500 mg of evening primrose oil per day. Baseline levels were 0.69 mmol/L, which decreased to 0.37 mmol/L after 2 months and 0.23 mmol/L after 3 months of use. Lithium levels increased within 6 weeks after stopping evening primrose oil, reaching 0.73 mmol/L; no clinical effect was noted.
Antiplatelet agents/Anticoagulants: weak interaction
Evening primrose oil could inhibit platelet aggregation and increase bleeding time. A clinical study in 12 patients with hyperlipidemia taking evening primrose oil (3 g/day) for 4 months showed a decrease in platelet aggregation and a 40% increase in bleeding time. Evening primrose oil was given as 6 softgel capsules of 500 mg/day. The daily dose contained 2.2 g of linoleic acid and 240 mg of gamma-linolenic acid. Similar results were observed in animals given evening primrose oil or gamma-linolenic acid. The results of another clinical study suggest that evening primrose oil has considerable anticoagulant and antiplatelet activity in animals.
Precautions
Pregnant women: use with caution
In small studies of evening primrose that included pregnant women, 4 grams were used orally daily for up to 10 weeks during pregnancy without problems. Evening primrose has also been used safely during the last week of pregnancy to improve cervical ripening, although in a retrospective case series there was no improvement.
Breastfeeding: use with caution
Supplementation with evening primrose oil during lactation results in the secretion of high levels of gamma-linolenic acid into breast milk; however, this fatty acid is normally present in significant amounts in breast milk.
Surgery: avoid
Gamma-linolenic acid has antiplatelet effects. Gamma-linolenic acid may cause excessive bleeding if used perioperatively. It is recommended to stop taking gamma-linolenic acid at least 2 weeks before surgery.
