Centuries ago, Native Americans and pilgrims ate evening primrose flowers to relieve hemorrhoids, stomachaches, sore throats and bruising. Europeans exploring the Americas brought the root of the pretty yellow flower home to Germany and England, where it was called the "king's cure all" because of its many healing properties.
The evening primrose, an annual that grows wild in North America and blooms only in the evening, contains an oil rich in essential fatty acids that our body needs to regulate inflammation, blood pressure, clotting, fluid balance and hormone production [source: Hudson].
Like olives and nuts, evening primrose oil is rich in Vitamin E. But its real claim to fame is its high concentration of gamma-linolenic acid (GLA) -- a fatty acid we can only get in the foods we eat that helps provide energy, maintain body temperature, insulate nerves and protect bodily tissues [source: Brown].
Today, the oil extracted from its seeds is made into capsules and ingested to treat such ailments as eczema, arthritis, diabetes, PMS, infertility, heart disease and schizophrenia. Some midwives swear it helps induce labor by softening the cervix. Doctors in Sweden are studying whether it can slow the aging process [source: Brown].
Is this the miracle drug we've all been waiting for? Not exactly. Scientific studies have found little evidence that it has any effect on these conditions, including claims that it can cure cancer, multiple sclerosis, infertility and the darker (and hotter) side of menopause [source: Mayo Clinic]. But that doesn't mean that it's impossible.
Read on to find out how GLA works and what this could mean for you.
Evening Primrose Oil Benefits
Evening primrose oil has a high concentration of gamma-linolenic acid (GLA) -- a fatty acid with a long name and an even longer list of functions it helps control in your body. When you eat food or take a supplement that contains this fatty acid, your body converts it into a hormone-like substance called prostaglandin E1, which stimulates contraction of the blood vessels [source: Whole Health MD].
Because of this anti-inflammatory effect, evening primrose oil has been used to treat a wide range of aches and pains caused by swelling, such as bloating, breast tenderness and cramping associated with PMS and joint pain in patients with rheumatoid arthritis. It's also been used to treat numbness and tingling in diabetics, skin problems like eczema, acne and rosacea, and patients with high cholesterol, multiple sclerosis and osteoporosis [source: Mayo Clinic].
The benefit of taking evening primrose oil is increasing the levels of GLA in your body, which could be low if you're not eating enough of the right fats, drink too much alcohol, have low thyroid function, or are undergoing radiation treatment [source: Brown].
But whether it will make your pimples or hot flashes go away remains unproven. In fact, scientific studies to support the claims that evening primrose oil helps cure any of these conditions are inconclusive. Most have been too small or poorly designed to produce reliable results, with one exception: eczema.
In a report by the Mayo Clinic, researchers gave evening primrose oil a "B" on a grading scale from A to F on the amount of evidence that supports claims it relieves itching, inflammation and flaking in patients with eczema [source: Mayo Clinic].
For most of the other conditions -- including multiple sclerosis, diabetes, breast pain, arthritis, high blood pressure and osteoporosis -- Mayo researchers gave the evening primrose oil a "C," or "unclear evidence" that it has any impact. For treatment of PMS and menopause, primrose oil got a "D" for lack of proof of its effectiveness [source: Mayo Clinic].
But for the same reason evening primrose oil may not help you, it probably won't hurt you either. Read on to find out why.
Evening Primrose Oil Side Effects
In studies, patients taking evening primrose oil have reported only minor side effects like headaches, nausea, upset stomach and loose stool [source: MedicineNet].
Because evening primrose oil may cause uterine contractions, it is not recommended for pregnant women. Patients with blood disorders or those taking blood thinners are also discouraged from using it [source: Memorial Sloan-Kettering Cancer Center].
In one study, researchers found it increased the risk of epilepsy in schizophrenic patients taking anti-psychotic medications like Thorazine and Prolixin. Another study found it could increase the number of seizures in patients with seizure disorder who underwent surgery requiring anesthesia [source: Mayo Clinic].
Remember, like all herbal remedies, evening primrose oil has not been approved by the FDA, which considers herbs dietary supplements rather than drugs. That's why they don't undergo rigorous clinical review before being released on the market. So like all things you put into your body, you should exercise caution. But if you're trying to get pregnant, you may want to throw caution to the wind -- at least where evening primrose oil is concerned. Read on to find out why.
Evening Primrose Oil and Pregnancy
There are plenty of old wives' tales about pregnancy. Wearing briefs reduces a man's sperm count. Conceiving on a full moon means you'll have a girl. Carrying low means it's a boy; carrying high means it's a girl. You need hot water during childbirth.
Is evening primrose oil one more? Possibly. Manufacturers of herbal fertility treatments claim that taking evening primrose oil can help a woman conceive by making her cervical mucus more stretchable and slippery, enabling the sperm to move more quickly through the uterus and into the fallopian tube [source: Baby Hopes].
Taking evening primrose oil supposedly increases a woman's "egg white" cervical mucus during ovulation, which helps the sperm stay viable longer and move more quickly toward the egg [source: Labor of Love]. As promising as it sounds, be aware that no scientific studies have confirmed its effectiveness for making babies.
Evening primrose oil has been used to help induce labor. Because it contains GLA, it's considered a good source of prostaglandins, which can help soften the cervix and prepare it to open [source: Birthing Naturally]. It's the same reason some people claim having sex can induce labor. Semen also contains prostaglandins, which stimulates moisture production at the mucus membranes.
Because it may cause contractions, it is recommended that you don't take evening primrose oil until you are at least 34 weeks into your pregnancy [source: Hudson]. You can take it orally or apply it directly to your cervix using your fingers or by inserting the capsule vaginally.
And again, evening primrose oil's ability to induce labor is still strictly theory. Some midwives swear by it, but most experts say it does nothing more than what the body was already ready to do naturally.
Read on to learn about its potential in affecting your brain chemistry.
Evening Primrose Oil and Brain Health
There are still plenty of questions about whether evening primrose oil can help treat brain-related conditions like hyperactivity, attention deficit hyperactivity disorder (ADHD), multiple sclerosis, depression, schizophrenia and Alzheimer's disease.
In one study involving psychiatric patients with tardive dyskinesia (abnormal, involuntary movements) who were given primrose oil for four months, researchers found the oil did nothing to stop the patients' involuntary movements, but did help improve their memory and calm their mental state [source: Hudson]. In studies of primrose oil's impact on children with attention-deficit/hyperactivity disorder (ADHD), the results have been mixed [source: Mayo Clinic].
The reason researchers even consider evening primrose oil for treating these types of conditions goes back to our friend, GLA. The importance of GLA, an omega-6 fatty acid also found in borage seeds and black current seeds, is that the body converts it to prostaglandin E1, which regulates body activity, including brain functioning [source: Schmidt].
Prostaglandin E1, considered a "messenger" in the brain, is vital to regulating nerve impulses -- one reason some experts believe that increasing prostaglandin E1 in the brain can improve things like memory, mood, impulse control and concentration [source: Schmidt].
But like all the alleged health benefits of evening primrose oil, the jury is still out. For more on the research that has been done thus far, see the links on the next page.
Related HowStuffWorks Articles
- Baby Hopes. "Evening Primrose Oil - Its Role in Trying to Conceive." (Accessed 3/10/09)http://www.babyhopes.com/articles/epo.html
- Birthing Naturally. "Evening Primrose Oil." (Accessed 3/10/09)http://www.birthingnaturally.net/cn/natural/primrose.html
- Brown, Marian. "Evening Primrose Oil." Holistic Health News. (Accessed 3/10/09)http://www.hhnews.com/epo.htm
- Early-Pregnancy-Tests. "Evening Primrose Oil." (Accessed 3/10/09)http://www.early-pregnancy-tests.com/epo.html
- Hudson, Jessica. "Natural Induction Methods." Maternity Corner. (Accessed 3/10/09)http://www.maternitycorner.com/mcmag/articles/preg0007.html
- Hudson, Tori. "Evening Primrose Oil." Bioriginal Publishing, October 2000. (Accessed 3/10/09)http://www.fatsforhealth.com/library/libitems/Evening_Primrose_Oil.php
- Mayo Clinic. "Evening Primrose Oil (Oenothera biennis L.)" (Accessed 3/10/09)http://www.mayoclinic.com/health/evening-primrose-oil/NS_patient-Primrose
- MedicineNet. "Generic Name: Evening Primrose Oil - Oral." (Accessed 3/10/09)http://www.medicinenet.com/evening_primrose_oil-oral/article.htm
- Memorial Sloan-Kettering Cancer Center. "Evening Primrose Oil." (Accessed 3/10/09)http://www.mskcc.org/mskcc/html/69216.cfm
- Schmidt, Michael A. Brain-Building Nutrition. Frog Books, 2007.
- The Labor of Love. "Trying to Conceive by Using Evening Primrose Oil." (Accessed 3/10/09)http://www.thelaboroflove.com/articles/trying-to-conceive-by-using-evening-primrose-oil-epo/
- University of Maryland Medical Center. "Evening Primrose Oil." (Accessed 3/10/09)http://www.umm.edu/altmed/articles/evening-primrose-000242.htm
- Whole Health MD. "Evening Primrose Oil." (Accessed 3/10/09)http://www.wholehealthmd.com/ME2/Apps/AWHN/Modules/Supplements/Print.asp?id=8715E6985B0845D091ECFD3F79A381C8&Title=evening+primrose+oil