Common Names: evening primrose oil, EPO

Scientific Name: Oenothera biennis

Background

• Evening primrose is a flowering plant native to the Americas that also grows in Europe and parts of Asia. Its yellow blossoms open in the evening and close during daylight. The oil derived from its seeds is a source of omega-6 fatty acids, including gamma-linolenic acid (GLA).

• Indigenous peoples traditionally used sap from its stems and leaves for minor skin issues like rashes, bruises, and surface wounds. The leaves were sometimes consumed to help with digestive issues and sore throats.

• Today, evening primrose oil is available as a supplement and promoted for various uses such as treating eczema, rheumatoid arthritis, breast tenderness, premenstrual syndrome, and menopausal symptoms. It’s also sometimes used in topical products or taken orally or vaginally near term in pregnancy to promote labor.

How Much Do We Know?

• There is a fair amount of clinical research on evening primrose oil for conditions like eczema, breast pain, and labor induction. However, the evidence for its effectiveness in other uses is limited.

What Have We Learned?

• Overall, there is not enough reliable evidence to confirm that evening primrose oil is helpful for any medical condition.

• Research indicates that taking evening primrose oil by mouth does not significantly relieve eczema symptoms.

• For breast pain, results suggest it performs no better than a placebo.

• Although it is believed that evening primrose oil might trigger labor through prostaglandin production, studies have not consistently proven this effect when taken orally or vaginally.

• There is currently insufficient data to support its use for rheumatoid arthritis, PMS, or menopause-related complaints.

What Do We Know About Safety?

• In most cases, oral evening primrose oil is considered safe for adults. Information on its use in children is not well established.

• The supplement is generally well tolerated, with possible mild digestive side effects like upset stomach, nausea, or diarrhea.

• If you're taking any medications, it’s important to check with your healthcare provider before using herbal remedies due to possible interactions.

• Though many women use evening primrose oil during pregnancy or while breastfeeding, its safety in these circumstances is not fully verified. When used late in pregnancy for labor induction, side effects are typically mild, but its long-term safety remains unknown. It does raise GLA levels in breastmilk but hasn’t been shown to harm infants.

Keep in Mind

• Always communicate openly with your healthcare professionals about any complementary or alternative products you use. Working together allows for informed and safe decisions about your care.

• Herbal supplements are regulated differently than medications. Many are sold as dietary supplements, which means they don’t require FDA approval before hitting the market. The manufacturers are responsible for making sure their products are safe and appropriately labeled before they are sold.

• If there’s a concern about a dietary supplement’s safety, regulatory agencies can step in to investigate and take action to protect consumers. Until then, most herbal products are available without the same level of testing as prescription drugs.

For More Information

• Getting the Most from Dietary Supplements

• Understanding How Medications and Supplements May Interact

• How to Interpret Scientific Research Articles

NCCIH Clearinghouse

Offers general details on complementary health practices, including publications and access to scientific literature. It does not give medical advice or referrals.

Phone (toll-free): 1-888-644-6226

TRS: 7-1-1

Email: [email protected]

PubMed®

This is a resource by the National Library of Medicine featuring abstracts from research journals in health and medicine.

Office of Dietary Supplements (ODS), NIH

ODS supports public knowledge about dietary supplements through education, research, and information sharing. It offers detailed fact sheets and publications on various supplements.

Email: [email protected]

Key References

• Ahmad Adni LL, Norhayati MN, Mohd Rosli RR, et al. A review and meta-analysis evaluating evening primrose oil for breast pain. Int J Environ Res Public Health. 2021;18(12):6295.

• Bamford JTM, Ray S, Musekiwa A, et al. Effect of oral evening primrose oil and borage oil for eczema. Cochrane Database Syst Rev. 2013(4):CD004416.

• Information on evening primrose from the Drugs and Lactation Database, NICHD. Updated May 2021.

• Data on evening primrose sourced from the NatMed Pro database. Accessed October 2023.

• Hutcherson TC, Cieri-Hutcherson NE, Lycouras MM, et al. Review of evening primrose oil use for aiding labor. Pharmacy (Basel). 2022;10(6):172.

• Kenda M, Glavač NK, Nagy M, et al. Review of herbal remedies for menopause and other women’s health issues. Molecules. 2021;26(24):7421.

• Kloter E, Albanese F, Schweighoffer R, et al. Herbal treatments in pediatric dermatology—A systematic review. Complement Ther Med. 2023;74:102942.

This content is in the public domain and may be freely reproduced.

The NCCIH shares this information to support informed decisions. It is not a replacement for professional medical advice. Always consult your healthcare provider before starting or stopping any treatment or supplement. Mention of products or services in this material does not imply endorsement.