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Dietary supplements are a popular option for people who want to treat physical symptoms with natural products. Evening primrose oil, derived from a flower, has been consumed for years as a food source and for medicinal purposes. However, research is lacking to support the benefits of evening primrose capsules. Check with your health care provider before taking any supplements to make sure they're safe for you.

Read more: The Side Effects of Evening Primrose Oil

Evening Primrose Capsules

Evening primrose supplements are taken in capsule form. The oil's medicinal ingredient is gamma linolenic acid, a type of fatty acid. The recommended dosage for evening primrose varies based on the condition you're trying to treat. It's commonly available in 500 to 1,000 mg capsules.

Treatment for Eczema

Evening primrose oil has been used to treat eczema, an inflammatory condition of the skin. However, according to a study published in 2013 by the Cochrane Database of Systematic Reviews, a review of the research has concluded that it's not effective as a treatment for eczema, and further research is not recommended. The Cochrane Database of Systematic Reviews, also reported that side effects of taking evening primrose oil for more than one year can include increased risk of inflammation in the body, blood clot development and suppression of the immune system.

Premenstrual Syndrome Relief

Evening primrose oil capsules are sometimes taken to help treat premenstrual syndrome (PMS). Symptoms associated with this condition include bloating and breast pain, as well as irritability, mood swings, depression and anxiety.

The 2016 guidelines for PMS management published by the Royal College of Obstetricians and Gynaecologists indicate that evening primrose oil may be included as a complementary treatment for PMS. However, the study also points out that research in this area is outdated and limited.

Breast Pain Reduction

Evening primrose capsules are sometimes used to treat breast pain. This type of pain is often treated with medications that can have serious side effects. A study published in 2017 by the Journal of Education and Health Promotion suggests that evening primrose oil can help decrease breast pain. However, other supplements, such as flaxseed and vitamin E, have been shown to decrease breast pain as effectively as evening primrose oil or even better.

Read more: Flax Seeds: How Much Per Day?

Benefits for Diabetes

Evening primrose oil has been shown to help slow the progression of complications caused by Type 2 diabetes. According to a study published in 2016 by the International Journal of Pharmaceutical Sciences Review and Research, the addition of evening primrose oil to conventional diabetes medication that regulates blood sugar reduced blood pressure and levels of inflammation in people with Type 2 diabetes.

Safety of Evening Primrose Oil

The National Center for Complementary and Integrative Health notes that taking evening primrose oil intermittently is likely safe for most people, although it can cause gastrointestinal upset in some. However, there is no research to demonstrate that long-term intake of this supplement is safe.

Evening primrose oil can also cause complications in pregnancy and can interact negatively with other medications. Talk to your health care provider before taking this supplement.