Overview

Evening primrose oil comes from the seeds of a plant called Oenothera biennis. It is available over the counter as a dietary supplement and can also be found in some creams and lotions that are applied to the skin. People use evening primrose oil for many different reasons, but its benefits are not well defined. Common side effects may include headache, nausea, or upset stomach. Before using evening primrose oil, make sure to tell your health care provider about any health conditions you have or medicines you are taking.

Uses

What is evening primrose oil used for?

Evening primrose oil is used for many different reasons, but its benefits are not well defined. Some common reasons that people use evening primrose oil include the following.

• Breast pain (mastalgia)
• Eczema (atopic dermatitis)
• Menopause symptoms
• Premenstrual syndrome (PMS)
• Nerve pain (neuropathy)

Note: The FDA has not reviewed evening primrose oil for safety and effectiveness. Learn more about dietary supplements here.

How does evening primrose oil work (mechanism of action)?

Evening primrose oil is the oil that comes from the seeds of a plant called evening primrose (Oenothera biennis). It contains an essential fat called gamma-linolenic acid (GLA). Your body makes GLA from another fat called linolenic acid. But there is some concern that certain people may not be able to make enough GLA.

GLA is a specific type of unsaturated fat called an omega-6 fatty acid. This type of fat is thought to help reduce inflammation (swelling) and strengthen your skin barrier. If your body is not able to make enough GLA on its own, taking evening primrose oil can increase your GLA levels. This may help reduce inflammation in your body and improve skin health. But there is no clear way to know whether your body makes enough GLA. Also, the benefits of evening primrose oil are not well defined for any use, including breast pain, eczema, menopause, premenstrual syndrome (PMS), or nerve pain.

When evening primrose oil is applied to the skin, it is thought to help moisturize the skin and strengthen the skin barrier. This helps keep the skin from losing as much water. But the benefits of applying evening primrose oil to the skin are not well defined.

Herbal products like evening primrose oil naturally contain many different chemicals, such as GLA. The amounts of each chemical in a specific evening primrose oil product may vary. Different amounts of GLA may change the effects of evening primrose oil on the body. Some evening primrose oil dietary supplements are made to contain a certain amount of GLA.

How should I store evening primrose oil?

You should store evening primrose oil according to the product label. Most dietary supplements should be kept in a cool, dry location that is out of the reach of children and pets and not in direct sunlight.

Side Effects

What are the most common side effects of evening primrose oil?

The most common side effects of evening primrose oil are listed below. These side effects may vary depending on the dose or the specific product you are using. Tell your health care provider if you have any of these side effects that bother you.

• Headache
• Nausea
• Upset stomach

There may be other side effects of evening primrose oil that are not listed here. Contact your health care provider if you think you are having a side effect of a supplement. In the U.S., you can report side effects to the FDA at www.safetyreporting.hhs.gov or by calling 888-SAFEFOOD (888-723-3366). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of evening primrose oil?

While less common, the most serious side effects of evening primrose oil are described below, along with what to do if they happen.

Severe Allergic Reactions. Evening primrose oil may cause allergic reactions, which can be serious. Stop using evening primrose oil and get help right away if you have any of the following symptoms of a serious allergic reaction.

• Breathing problems or wheezing
• Racing heart
• Fever or general ill feeling
• Swollen lymph nodes
• Swelling of the face, lips, mouth, tongue, or throat
• Trouble swallowing or throat tightness
• Itching or skin rash
• Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
• Nausea or vomiting
• Dizziness, feeling lightheaded, or fainting
• Stomach cramps
• Joint pain

Precautions

Who should not use evening primrose oil?

Allergies to Ingredients. People who are allergic to any of the following should not use evening primrose oil.

• Evening primrose
• Evening primrose oil (EPO)
• Gamma-linolenic acid (GLA)
• Oenothera biennis
• Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific evening primrose oil products they stock.

What should I know about evening primrose oil before using it?

Evening primrose oil is a dietary supplement. It cannot be marketed to treat or cure a disease.

Read and follow the directions on the specific product you are using, or use it as recommended by your health care provider.

Keep evening primrose oil out of the reach of children.

Herbal products, such as evening primrose oil, naturally contain many different chemicals. The amount of each chemical in a specific evening primrose oil product can change for many reasons, including the area where the plant was grown, the weather during growth, the time of year when it was harvested, and the way that the seeds were processed after the plant was harvested. If you switch to a new bottle or a different brand, you may not have the same effects or side effects because of this variability. Talk to your health care provider if you have questions or concerns.

The FDA has not tested evening primrose oil products to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.

What should I tell my health care provider before using evening primrose oil?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know whether evening primrose oil is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions.Tell your health care provider if you have any of the following.

• Bleeding problems
• High blood pressure
• Kidney problems
• Liver problems

Other Medicines and Supplements.Evening primrose oil may interact with other medicines and supplements. Before using evening primrose oil, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how evening primrose oil could affect pregnancy or harm an unborn baby. Tell your health care provider if you are pregnant or plan to become pregnant.

Breastfeeding. Evening primrose oil passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed.

Interactions

Does evening primrose oil interact with foods or drinks?

There are no known interactions between evening primrose oil and foods or drinks.

It is unknown if drinking alcohol will affect evening primrose oil.

Does evening primrose oil interact with medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before using evening primrose oil.

• A blood thinner, which is a medicine used to treat or prevent blood clots
• A nonsteroidal anti-inflammatory drug (NSAID), such as ibuprofen, naproxen, and others, which is in many prescription and over-the-counter (OTC) products for pain, swelling, and fever
• An antiplatelet medicine, such as clopidogrel (Plavix), ticagrelor (Brilinta), aspirin/dipyridamole, or cilostazol, which is a medicine used to prevent blood clots

The interactions between evening primrose oil and medicines are not fully understood. As with most dietary supplements, the research on drug interactions with evening primrose oil is incomplete. Always check with your health care provider before using evening primrose oil with any medicines.

Dosing

What should I do if I accidentally use too much evening primrose oil?

If you or someone else has used too much evening primrose oil, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

Evening primrose oil is available as a dietary supplement in many different doses and forms. It is also available in some creams or lotions that are applied to the skin. Read the product label closely and speak with a health care provider about how to use evening primrose oil safely. Do not use double or extra doses, even if you miss a dose.