Evening Primrose

Introduction

This fact sheet provides basic information about evening primrose oil, including its common names, uses, potential side effects, and resources for further information. Evening primrose is a plant native to North America but also grows in Europe and parts of the Southern Hemisphere. It features yellow flowers that bloom in the evening. Evening primrose oil contains gamma-linolenic acid (GLA), an essential fatty acid necessary for growth and development, which must be obtained through diet.

Common Names

• Evening primrose oil
• EPO

Latin Names

• Oenothera biennis

What It Is Used For

• Eczema: Used since the 1930s for treating eczema, a condition characterized by inflamed, itchy, or scaly skin due to allergies or irritation.
• Inflammatory Conditions: More recently used for conditions like rheumatoid arthritis.
• Women’s Health: Used for breast pain related to the menstrual cycle, menopausal symptoms, and premenstrual syndrome (PMS).
• Other Conditions: Sometimes used for cancer and diabetes.

How It Is Used

Evening primrose oil is extracted from the evening primrose plant’s seeds and is typically available in capsule form.

What the Science Says

• Eczema: Evening primrose oil may have modest benefits for eczema, but study results are mixed. Most studies are small and poorly designed.
• Rheumatoid Arthritis: It may be helpful in rheumatoid arthritis.
• Breast Pain: Some clinical trials suggest benefits for breast pain, but well-designed trials have found no significant effect on menopausal symptoms or PMS.
• Other Health Conditions: Insufficient evidence supports its use for other health issues.

Side Effects and Cautions

• Evening primrose oil is generally well tolerated, with mild side effects such as gastrointestinal upset and headaches.
• It is essential to inform healthcare providers about complementary and alternative practices to ensure coordinated and safe care.

Sources

• Shahidi F, Miraliakbari H. Evening primrose (Oenothera biennis). In: Coates P, Blackman M, Cragg G, et al., eds. Encyclopedia of Dietary Supplements. New York, NY: Marcel Dekker; 2005:197-210.
• Evening primrose oil. Natural Medicines Comprehensive Database Web site. Accessed on July 6, 2007.
• Evening primrose oil (Oenothera biennis L.). Natural Standard Web site. Accessed on July 3, 2007.
• NCCAM National Institutes of Health