Evening Primrose: Benefits, Dosage, Contraindications
Other name(s)
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Scientific name(s)
Oenothera biennis
Family or group:
Plants
Active ingredients:
Gamma-linolenic Acid
Linoleic Acid
Indications
Rating methodology
EFSA approval.
Rheumatoid Arthritis ✪✪✪✪✪
Two small clinical studies indicate that taking 6 grams of evening primrose oil per day for 12 months improves subjective symptoms but not objective symptoms of rheumatoid arthritis compared to placebo. Evening primrose oil was also evaluated in combination with other ingredients. A preliminary clinical study shows that taking 2.6 grams per day of evening primrose oil with a fish oil product of 2 grams per day for 12 weeks modestly reduced the overall symptom score, pain intensity, and number of tender joints compared to placebo, but not compared to taking the same fish oil product at a dose of 5 grams per day without evening primrose oil, suggesting a role played by evening primrose oil.
Posologie
Oral: seed
2.6 - 6 g
oil
Synergies
Evening primrose oil in patients with rheumatoid arthritis and side-effects of non-steroidal anti-inflammatory drugs
Effects of altering dietary essential fatty acids on requirements for non-steroidal 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 α-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. The improvements were significantly greater in patients with better-controlled diabetes. The glycated hemoglobin (HbA1C) level was not significantly different between treatment groups, indicating GLA had no effect on glycemic control. The results of another trial examined the vibration perception threshold, a different measure from previous trials. This randomized, double-blind, placebo-controlled study examined 51 patients with type 1 and type 2 diabetes and peripheral autonomic neuropathy who received 480 mg of GLA per day or a placebo for 1 year. At the end of the study, patients receiving evening primrose oil showed no improvement in the vibration perception threshold compared to 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 on adults, taking 2 to 3 grams of evening primrose oil orally twice daily for 3 weeks to 5 months appears to reduce the extent of atopic dermatitis and symptoms of itching and dryness. In children up to 18 years, some small clinical studies 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 to placebo. However, in other studies, evening primrose oil at doses of 2 to 8 grams per day in 1 to 2 divided doses for 12 to 16 weeks did not improve atopic dermatitis compared to baseline or placebo. The contradictory results may be due to differences in the initial severity of atopic dermatitis, the 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 high sensitivity to prolactin, which occurs at ovulation and increases 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 is the subject of various clinical trials. Two small clinical studies show that oral intake of 3 to 4 grams per day for 3 months, from the 15th day to the end of the menstrual cycle for 4 cycles, improves subjective PMS symptoms compared to placebo. In another double-blind, placebo-controlled randomized trial, the soothing effect of 180 mg of gamma-linolenic acid was compared to placebo on the clinical symptoms of 28 women suffering from PMS in three luteal phases. Irritable bowel syndrome was the most common symptom among women with PMS, followed by breast swelling, drowsiness, and rash. After the treatment, patients in the gamma-linolenic acid group had higher levels of gamma-linolenic acid and dihomo-gamma-linolenic acid in plasma phospholipids compared to the placebo group. Physical, mental, and social severity and duration of PMS, irritability improved in the gamma-linolenic acid group compared to 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 to 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 might 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 only reduces breast pain compared to baseline, but not compared to placebo. An observational study revealed that taking evening primrose oil 1300 mg twice a day for 6 weeks reduces pain associated with mastalgia compared to acetaminophen 500 mg twice a day.
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 depressive mood, irritability, and anxiety, by about 45% compared to baseline values. These changes were statistically significant compared to placebo. Evening primrose 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, depressive mood, and irritability compared to placebo. No effect was observed on plasma lipids, joint discomfort, cardiac discomfort, anxiety, exhaustion, 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 induces a reduction of 57% to 63% in subjective symptoms of menopause compared to 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 daily for 6 months reduces disability scores and relapse rates compared to baseline. Evening primrose oil as a rich source of omega 6-GLA, which are precursors of eicosanoids, constituents of cell membranes. The biochemical pathway of dietary gamma linolenic acid (GLA) metabolism ultimately leads to prostaglandin E1 (PGE1), which possesses strong anti-inflammatory activity and is often recommended for inflammatory and autoimmune conditions. If there is a partial EFA deficiency in MS, one might expect reduced formation of PGE1 and perhaps an increased synthesis of PGE2. The PGEl deficit would result in defective T lymphocyte function with increased susceptibility to infections and autoimmune lesions. Lymphocytes in patients with MS are known to behave abnormally in various tests, and there is clear evidence of a particular defect in suppressor T lymphocytes, one of whose functions is to modulate B lymphocyte responses. Correcting the PGEl deficit should tend to restore normal immunologic function.
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 indicates that evening primrose oil is traditionally used for the symptomatic relief of itching in acute and chronic states of dry skin.
Posologie
Cutaneous, oral: seed
4 - 6 g
oil
Itching ✪✪✪✪✪
The EMA indicates that evening primrose oil is traditionally used for the symptomatic relief of itching in acute and chronic states of dry skin.
Posologie
Cutaneous: seed
4 - 6 g
oil
Wrinkles ✪✪✪✪✪
Evening primrose oil is traditionally used for its soothing properties on skin rashes, dermatoses, or skin aging, externally. Internally, it is used to fight against the loss of elasticity of the epidermis and skin dryness.
Posologie
Oral: seed, buds
alcohol 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 anti-inflammatory effects. It reduces the production of interleukin-1-beta (IL-1-beta) which may be involved in inflammatory diseases such as rheumatoid arthritis. GLA is metabolized into dihomo-gamma-linolenic acid (DGLA), a precursor to prostaglandin E1, which inhibits inflammatory polymorphonuclear leukocytes. GLA may also competitively inhibit the synthesis of pro-inflammatory series 2 prostaglandins. DGLA is converted into 15-hydroxy-DGLA, blocking the conversion of arachidonic acid into inflammatory leukotrienes. GLA and DGLA seem to improve the balance between inflammatory and non-inflammatory prostaglandins and leukotrienes.
Usages associés
Antiplatelet/Anticoagulant
Evening primrose oil may decrease platelet aggregation and prolong bleeding time. In vitro research results suggest this could be due to the dihomo-gamma-linolenic acid (DGLA) component.
Dermatological Effect
Evening primrose oil has a high content of linoleic acid and gamma-linolenic acid; it strengthens the epidermal barrier, normalizes excessive water loss through the epidermis, regenerates the skin, and improves softness, after topical and oral applications. It also shows a notable moisturizing effect in patients with acne-treated by isotretinoin. Moreover, its high gamma-linolenic acid content provides anti-inflammatory eicosanoids, preventing epidermal hyperproliferation through their anti-proliferative properties.
Usages associés
Cardiovascular
Evening primrose oil, rich in gamma-linolenic acid (GLA), seems to help reduce triglyceride levels. This reduction may result from two mechanisms: on one hand, the inhibition of triglyceride production in the liver, and on the other, the activation of enzymes that break down triglycerides into free fatty acids. Additionally, evening primrose oil may improve HDL cholesterol levels, which benefits cardiovascular health and could help prevent complications like atherosclerosis and coronary heart disease.
Safety dosage
Adult from 12 years: 2 g - 6 g
Single dose: 2-3 g. Daily dose: 4-6 g. Evening primrose has been used safely at doses of up to 6 grams per day for one year.
Child from 5 to 12 years: 2 g - 3 g
In children up to 5 years old, 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 old, 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 has been applied to affected skin areas twice daily for up to 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) alongside their usual treatment (Phenothiazines for schizophrenia) of which 3 patients developed seizures. In another study, 3 long-term schizophrenic patients taking Evening primrose oil were hospitalized for worsening schizophrenia, and their EEGs showed temporal lobe epilepsy. However, no epileptiform convulsions or other events were reported in a crossover study with 48 patients taking phenothiazines with Evening primrose oil for 4 months. Evening primrose oil may potentially increase the well-known epileptogenic effects of Phenothiazines.
Ritonavir: moderate interaction
In a case report, an HIV-positive patient taking evening primrose oil (Efamol) with lopinavir/ritonavir experienced increased lopinavir serum levels up to 15.2 mg/l. Six weeks after stopping evening primrose oil, lopinavir levels returned to the normal range of 5 to 10 mg/litre. When the patient resumed evening primrose oil for a week, their lopinavir level increased from 6.69 to 8.11 mg/l. It's 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 research.
Lopinavir: moderate interaction
A 47-year-old HIV-positive man taking: Lopinavir boosted by Ritonavir 533/133 mg twice a day, Tenofovir 245 mg/day, and Lamivudine 150 mg twice a day, developed persistent diarrhea (diarrhea 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. Lopinavir level returned to normal (5 to 10 mg/L) 6 weeks after stopping all herbal preparations. The patient resumed evening primrose oil for 1 week, and the Lopinavir level increased 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 lithium dose 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 of stopping evening primrose oil, reaching 0.73 mmol/L; no clinical effects were noted.
Antiplatelet/Anticoagulant: weak interaction
Evening primrose oil may inhibit platelet aggregation and increase bleeding time. A clinical study with 12 patients with hyperlipidemia taking Evening primrose oil (3g/day) for 4 months showed a decrease in platelet aggregation and a 40% increase in bleeding time. Evening primrose oil was given in the form of 6 soft capsules of 500 mg/day. The daily dose contained 2.2 g of linoleic acid and 240 mg of gamma-linolenic acid. Similar results in animals receiving 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 with evening primrose involving pregnant women, 4 grams have been used orally daily for up to 10 weeks during pregnancy without issues. Evening primrose has also been used safely during the last week of pregnancy to improve the maturation of the cervical canal, although in a retrospective case series, there was no improvement.
Breastfeeding women: use with caution
Supplementation with evening primrose oil during lactation leads to the secretion of high levels of gamma-linolenic acid in breast milk; however, this fatty acid is normally present in significant quantities in breast milk.
Surgical intervention: avoid
Gamma-linolenic acid has antiplatelet effects. Gamma-linolenic acid may cause excessive bleeding if used peri-operatively. It is advised to stop taking gamma-linolenic acid at least 2 weeks before surgery.
