Each capsule contains: Oenothera biennis 500 mg. Other Ingredients: Gelatin, Glycerin, Purified Water, Tocopherol.
Brand name products often contain multiple ingredients. To read detailed information about each ingredient, click on the link for the individual ingredient shown above.
In 2004, Canada began regulating natural medicines as a category of products separate from foods or drugs. These products are officially recognized as "Natural Health Products." These products include vitamins, minerals, herbal preparations, homeopathic products, probiotics, fatty acids, amino acids, and other naturally derived supplements.
In order to be marketed in Canada, natural health products must be licensed. In order to be licensed in Canada, manufacturers must submit applications to Health Canada including information about uses, formulation, dosing, safety, and efficacy.
Products can be licensed based on several criteria. Some products are licensed based on historical or traditional uses. For example, if an herbal product has a history of traditional use, then that product may be acceptable for licensure. In this case, no reliable scientific evidence is required for approval.
For products with non-traditional uses, some level of scientific evidence may be required to support claimed uses. However, a high level of evidence is not necessarily required. Acceptable sources of evidence include at least one well-designed, randomized, controlled trial; well-designed, non-randomized trials; cohort and case control studies; or expert opinion reports.
Finished products licensed by Health Canada must be manufactured according to Good Manufacturing Practices (GMPs) as outlined by Health Canada.
Below is general information about the effectiveness of the known ingredients contained in the product Evening Primrose Oil 500 mg. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
INSUFFICIENT RELIABLE EVIDENCE to RATE
Below is general information about the safety of the known ingredients contained in the product Evening Primrose Oil 500 mg. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
LIKELY SAFE ...when used orally and appropriately. Evening primrose oil has been used safely in doses up to 6 grams daily for up to 1 year (7566,7567,8926,12036,20512,49286,49360,109426). There is insufficient reliable information available about the safety of evening primrose oil when used topically. There is also insufficient reliable information available about the safety of evening primrose seed, flower, or leaf when used orally or topically.
CHILDREN: POSSIBLY SAFE
when evening primrose oil is used orally and appropriately, short-term.
In children up to 5 years of age, doses of evening primrose oil up to 3 grams daily have been used safely for 5 months (20512,49273), and 0.5 grams/kg daily has been used safely for 8 weeks (7570). In children up to 12 years of age, doses of 4-6 grams daily have been used safely for 3-5 months (7565,7566,20512,49286). ...when used topically and appropriately, short-term. In children 2-10 years of age, evening primrose oil has been applied to affected areas of the skin twice daily for up to 3 months (96718). There is insufficient reliable information available about the safety of evening primrose seed, flower, or leaf when used orally or topically.
PREGNANCY: POSSIBLY SAFE
when evening primrose oil is used orally and appropriately.
In small studies of evening primrose oil for pre-eclampsia, 4 grams has been used orally daily for up to 10 weeks during pregnancy with apparent safety (1409,20525). Evening primrose oil has also been used safely during the last week of pregnancy to improve cervical ripening (20524,96717), although in one retrospective case series improvement was lacking and there was a trend toward prolonged labor, increased rates of arrest of descent, and increased oxytocin requirements (1411). Evening primrose oil has also been linked to a case report of petechiae and ecchymoses in a newborn infant whose mother took a total of 6.5 grams during the week before giving birth (16303); use with caution, especially in high doses.
LACTATION: POSSIBLY SAFE
when evening primrose oil is used orally.
Supplementation with evening primrose oil during lactation results in the secretion of high levels of the constituent gamma linolenic acid into breast milk (1982); however, this fatty acid is normally present in significant amounts in breast milk (11884).
Below is general information about the interactions of the known ingredients contained in the product Evening Primrose Oil 500 mg. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
 Details
Evening primrose oil contains gamma linolenic acid (GLA). There is preliminary clinical evidence that GLA can reduce platelet aggregation and prolong bleeding time (1979).
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Theoretically, evening primrose may increase the levels and clinical effects of CYP2C9 substrates.
Details
In vitro research shows that linoleic acid, a constituent of evening primrose oil, inhibits CYP2C9 (21017).
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Theoretically, concomitant use of lithium with evening primrose oil might decrease lithium levels and effects.
Details
In a case report, a patient on a stable dose of lithium for 10 years experienced a reduction in lithium levels after taking evening primrose oil 500 mg daily. 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 discontinuing evening primrose oil, to 0.73 mmol/L; no clinical effects were noted (96715).
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Theoretically, evening primrose oil might increase the levels and effects of lopinavir.
Details
In a case report, an HIV patient who took evening primrose oil (Efamol) along with lopinavir/ritonavir experienced an increase in serum levels of lopinavir to 15.2 mg/L. Six weeks after discontinuing evening primrose oil, levels of lopinavir returned to the normal range of 5-10 mg/L. When re-challenged with evening primrose oil for a week, the patient's lopinavir levels increased from 6.69 to 8.11 mg/L. It is suspected that evening primrose oil increases levels of lopinavir by inhibiting cytochrome P450 3A4 (CYP3A4), which metabolizes lopinavir (93578). However, this effect has not been reported in other research.
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Theoretically, taking evening primrose oil with phenothiazines might increase the risk of convulsions.
Details
Evening primrose oil contains gamma-linolenic acid (GLA). There is some concern that taking supplements containing GLA might cause seizures, or lower the seizure threshold, when taken with phenothiazines (88187). In one report, three patients with schizophrenia who had received phenothiazines developed EEG changes suggestive of temporal lobe epilepsy after starting treatment with GLA, although none experienced an actual seizure (21013). In another report, two patients with schizophrenia who were stabilized on phenothiazines developed seizures when evening primrose oil 4 grams daily was added. One of these patients had a prior history of seizures (21010). It is unclear whether evening primrose oil had any additive epileptogenic effects with the phenothiazines; there is no evidence that taking evening primrose oil alone causes seizures (88187).
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Below is general information about the adverse effects of the known ingredients contained in the product Evening Primrose Oil 500 mg. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
General
...Orally and topically, evening primrose oil is generally well tolerated.
There is limited reliable information available regarding the safety or adverse effects of other parts of the plant.
Most Common Adverse Effects:
Orally: Abdominal pain and distention, diarrhea, dyspepsia, flatulence, nausea, and vomiting.
Dermatologic ...Orally, use of evening primrose oil has been associated with reports of skin rash and acne (9156,9794,49338). There is a case report of extensive but transient petechiae and purpuric ecchymoses in a newborn infant whose mother had consumed raspberry leaf tea and a total of 6.5 grams of evening primrose oil orally and vaginally during the week prior to delivery. The infant had a normal platelet count and no signs of hemorrhage, and was discharged healthy at 3 days of age (16303).
Gastrointestinal ...Gastrointestinal complaints, including abdominal pain, distension and fullness, nausea and vomiting, diarrhea, dyspepsia, and flatulence are the most common adverse effects of evening primrose (8926,9794,20533,49188,49286,49339,49365,65864,88184,102556). Often these effects resolve with continued use. Altered taste has also been reported (49339).
Hematologic ...There is preliminary clinical evidence that evening primrose oil can decrease platelet aggregation and prolong bleeding time. In a small study of patients with hyperlipidemia, taking evening primrose oil 3 grams daily for 4 months was associated with a 40% increase in bleeding time, and decreases in ADP- and epinephrine-induced platelet aggregation of 50% and 60% respectively (1979). There is also a case report of diffuse ecchymoses and petechiae in a neonate whose mother had consumed 6.5 grams of evening primrose oil over the week prior to delivery (16303).
Neurologic/CNS
...Cases of dizziness (9794) and headache (88184) have been reported with evening primrose oil when used orally.
There is a report of seizures in a patient taking evening primrose oil and receiving anesthesia; however, the patient was also taking other drugs and it is therefore unclear if evening primrose was the cause (613). There is also concern that evening primrose oil might cause seizures, or lower the seizure threshold, in patients with schizophrenia who are treated with phenothiazines. This is based on limited data from two studies published in the 1980s. In one report, three patients with schizophrenia who had received phenothiazines developed EEG changes suggestive of temporal lobe epilepsy after starting treatment with evening primrose, although none experienced an actual seizure (21013). In the other report, two patients with schizophrenia who were stabilized on phenothiazines developed seizures when evening primrose oil 4 grams daily was added. One of these patients had a prior history of seizures (21010). There is no evidence that evening primrose taken alone, without medications known to lower the seizure threshold, can cause seizures (88187).
Other ...Weight gain has been reported in individuals receiving evening primrose oil (49338).
