Natural Health Products

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Evening Primrose Oil

General Information

Evening primrose is a plant native to North America, but it grows in Europe and parts of the southern hemisphere as well. It has yellow flowers that bloom in the evening. Evening primrose oil contains gamma-linolenic acid (GLA).

Common Name(s)
evening primrose oil, EPO
Scientific Name(s)
Oenothera biennis
How is this product usually used?

Evening primrose oil is extracted from the seeds of the evening primrose. The oil is usually put into capsules for use. The recommended dose is 1.3 g to 6 g of evening primrose oil per day.

What is this product used for?

Evening primrose oil is used as a supplement to maintain good health. It’s a source of healthy fatty acids such as omega-6 and linoleic acid. It may be used in treating a variety of other health conditions such as diabetes, osteoporosis, and psoriasis.

Your health care provider may have recommended this product for other conditions. Contact a health care provider if you have questions.

What else should I be aware of?

There is not enough evidence to support the use of evening primrose oil for any health condition.

Evening primrose oil is well tolerated by most people, when taken for short periods of time. Common side effects include abdominal pain or swelling, diarrhea, gas, nausea, upset stomach, and vomiting.

The safety of long-term use of evening primrose oil has not been established.

Evening primrose oil may interact with the following:

  • anticoagulants (e.g., apixaban, warfarin)
  • antiplatelets (e.g., acetylsalicylic acid (ASA), clopidogrel)
  • certain types of antipsychotics called phenothiazines (e.g., chlorpromazine, prochlorperazine)
  • lithium
  • lopinavir
  • ritonavir

Evening primrose oil should not be used by those who experience seizures. Stop taking evening primrose oil at least 2 weeks before surgery.

Before taking any new medications, including natural health products, speak to your physician, pharmacist, or other health care provider. Tell your health care provider about any natural health products you may be taking.

  1. Health Canada. Drugs & Health Products. Monograph – Evening Primrose Oil. 
  2. Natural Medicines Comprehensive Database. Evening Primrose.

All material copyright MediResource Inc. 1996 – 2020. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.