Health Benefits of Evening Primrose Oil

Written by Alicia Racelis, PhD, WebMD Editorial Contributor
Medically Reviewed by Melinda Ratini, MS, DO on May 09, 2025
6 min read

Evening primrose oil (EPO) comes from the seeds of a wildflower called Oenothera biennis. The seed oil is rich in fatty acids called linoleic acid (LA) and gamma-linolenic acid (GLA). These essential fatty acids may boost skin health, eye health, and more.

Native Americans used the oil to lower skin inflammation, heal wounds, and treat bruises. Its yellow flowers bloom after sunset. Once native to North America, the plant has spread all over the world. 

In 17th-century Europe, the herb became a popular folk remedy and earned the nickname “King’s cure-all.” Other names include golden candlestick, hogweed, night willow herb, and fever plant.

EPO is sold as a dietary supplement at grocery stores, pharmacies, and online. Although some claims remain unclear, here are some possible health benefits of EPO.

Evening primrose oil contains many helpful compounds, such as proteins, vitamins, and fatty acids, which may benefit your health. These include:

Evening primrose oil contains about 74% linoleic acid and 10% gamma-linolenic acid. Your body can convert GLA to prostaglandins. These hormone-like substances are involved with:

  • Inflammation
  • Pain
  • Blood pressure
  • Blood clotting
  • Fluid balance (hydration)
  • Hormone production

The antioxidant and anti-inflammatory effects of EPO may help your immune system. But there isn't enough evidence to treat any health condition with EPO.

Keep in mind the FDA doesn't approve dietary supplements the way it does medications. Companies making herbal supplements are responsible for their safety. Although it's still unclear, many companies promote EPO for dry eyes and skin, menstrual problems, and more.

Dry eye relief

Some studies suggest EPO may help with dry eyes. Other studies don't show a difference. A few smaller studies with Sjögren's syndrome showed benefit using EPO. But without more research, it's unclear if the oil helps lower burning, dryness, and light sensitivity.

Skin health

EPO is rich in GLA, vitamins, and minerals. The oil may help eczema (atopic dermatitis) by lowering redness, itching, and crusting. But studies are unclear about EPO and skin health. A review of 19 studies showed no difference in eczema using EPO.

Premenstrual syndrome (PMS) relief

Although many people take EPO for PMS, some studies show it doesn't help at all. There aren't enough studies to prove that the essential fatty acids in EPO can help PMS.

Menopausal relief

Some claim evening primrose oil can help relieve hot flashes, but it's unclear. EPO may help lower hot flash intensity, frequency, and duration. But more research is needed to find out if EPO is helpful for menopausal relief.

Breast pain

EPO is used all over the world to treat breast pain. Research shows mixed results about evening primrose oil's benefits for mastalgia (breast pain). Because it's low-risk, some doctors may suggest EPO.

The oil may have some estrogen-like properties. So, avoid EPO if you're pregnant, have a hormone-sensitive condition, or have cancer.

Arthritis pain reduction

The GLA in evening primrose oil doesn't help with rheumatoid arthritis (RA). Although a small study showed that a few people felt better taking EPO, the oil doesn't stop joint damage. If untreated, RA can cause joint damage. Talk to your doctor about the best treatment for RA.

Diabetic neuropathy

EPO probably doesn't help ease diabetic neuropathy pain. While two studies suggest that GLA may help lower pain, it's unclear if the GLA in EPO can help with neuropathy.

Inducing labor

Don't take evening primrose oil if you're pregnant. EPO may raise your chances of pregnancy complications. There's also no strong evidence to support that EPO can help induce labor. The results have not been consistent.

You'll only find evening primrose oil from the wildflower seeds. But the two essential fatty acids found in evening primrose oil are also found in other plants. You'll find gamma-linolenic acid in plants such as:

  • Black currant oil
  • Borage oil
  • Certain fungal oils
  • Spirulina (a blue-green alga)

EPO also contains linoleic acid. You can find this polyunsaturated fatty acid in vegetable oils such as:

  • Sunflower
  • Safflower
  • Soybean
  • Corn
  • Canola

For most people, evening primrose oil is usually safe for short short-term use. But sometimes, you can get minor side effects. Try adding EPO slowly to your diet. If symptoms don't go away, stop taking it and talk to your doctor.

With EPO, you may get symptoms such as:

  • Nausea
  • Stomach pain
  • Loose stools
  • Headache

Stomach pain and diarrhea may mean you're taking too much EPO.

Who should not take EPO?

EPO is rich in omega-6 fatty acids and may act like estrogen. The oil may thin your blood, increase seizure risk, or raise your blood pressure, too. Don't take EPO if you have:

  • Seizures
  • Schizophrenia
  • Bleeding problems (stop taking EPO before any procedure or surgery)
  • Blood disorders
  • Hormone-sensitive cancers
  • Pregnancy (EPO can raise your risk of delivery complications and newborn bruising)
  • Breastfeeding (chestfeeding)

Evening primrose medication interactions

Cytochrome P450 3A4 is an enzyme that helps your body break down certain medicines. The GLA in evening primrose oil likely interacts with the enzyme. EPO can raise or lower some medication levels. 

Avoid EPO if you take:

  • Blood thinners: EPO can raise your bleeding risk if you're on any anticoagulants, antiplatelets, or herbal medicines to prevent blood clots.
  • Blood pressure medications: Ask your doctor to be sure.
  • Certain antivirals, such as lopinavir-ritonavir (Kaletra): The oil can increase their levels in your bloodstream.
  • Phenothiazines: EPO can raise your seizure risk.
  • SSRI antidepressants

You can buy evening primrose oil as a nutritional supplement. There's no recommended daily amount for the dietary herb. The 1-gram capsule often contains:

  • 0.62 gram LA
  • 0.08 gram GLA

In clinical studies, EPO soft gels came in the following sizes:

  • 250 milligrams
  • 500 milligrams
  • 1,000 milligrams
  • 1,300 milligrams

There's no safe or standard EPO dose recommended. But in some studies, the total EPO dose ranged from 1,000 to 8,000 milligrams each day.

Always talk to your doctor about how much EPO is right for your health. They can review your medications, dosing instructions, and any interactions from a reliable supplement brand.

What is evening primrose carrier oil good for?

Key fatty acids help evening primrose oil (EPO) act as a carrier oil. Health and beauty skin care products may contain EPO.

The oil is a rich source of vitamin E (67%), linoleic acid (74%), and gamma-linolenic acid (9%). These antioxidants may help soothe, moisturize, and protect your skin.

What is the main use of evening primrose?

Using evening primrose oil for skin conditions such as eczema has the most support. But there isn’t enough strong evidence to confirm that EPO can treat any medical condition.

How does evening primrose oil affect hormones?

By raising your gamma-linolenic acid, EPO may balance hormone-like compounds called prostaglandins. Prostaglandins affect inflammation and hormone-related symptoms such as breast pain, bloating, and cramps.

Why do people use evening primrose oil?

Although EPO isn't suggested to treat any health condition, people claim the high levels of GLA are good for:

  • Premenstrual syndrome (PMS)
  • Eczema, atopic dermatitis, and other skin conditions
  • Breast pain
  • Menopausal relief (hot flashes)
  • Dry eyes

But many studies show no reason to suggest evening primrose oil helps these medical conditions.

What are the risks of taking evening primrose oil?

Most people can take EPO without problems. But avoid EPO if you're pregnant, have cancer, hormone-sensitive conditions, seizure risk, or take medication.

Sometimes, you can get mild side effects from EPO, such as:

  • Headache
  • Stomach upset
  • Nausea
  • Diarrhea

Also, EPO can raise or lower some medicine levels in your bloodstream. Always talk to your doctor before taking any supplement.