6 Benefits of Evening Primrose Oil for Rheumatoid Arthritis [UPDATED]

Rheumatoid arthritis (RA) is one type arthritis which is described as an autoimmune disease, which means this arthritis results when your immune system attacks your own body tissues.

Rheumatoid arthritis is characterised by pain, inflammation, stiffness and problem in joints functioning.

This type of arthritis is seen more in women as compared to men.

Studies have revealed that around 1.5 million people in America are found to suffer from this type of arthritic problem.

The main causes of RA are hereditary, environmental and hormonal factors.

And the treatment includes medicines such as NSAIDs and DMARDs drugs, surgery and lifestyle changes such as proper rest, exercise, joint care, stress reduction, and diet management.

What is Evening Primrose Oil?

Evening primrose oil is the oil produced from evening primrose plant (Oenothera biennis, O. biennis) which a biennial herbaceous forb (broad-leaved herb), belonging to family of Onagraceae.

The plant gets its name because of its large fragrant flowers which bloom in the evening and partially or fully closed during day time.

The plant can thrive in various adverse climatic conditions such as sandy soils, in dunes, meadows and also in wasteland.

Evening primrose plant is found native to North America but also grows in Europe and other parts of Sothern Hemisphere zone.

It is observed that it is grown commercially in more than 30 countries.

Evening primrose oil (EPO) is an oil extracted from the seeds of these plants which has been used from ancient times as herbal remedy for treatment of number of ailments but mainly skin related problems such as eczema (inflammation of the skin). Evening primrose oil also helps in improving the pains related to menstrual cycle, menopausal problems and breast pain in women. Recently studies have proved that it is also very effective in inflammatory related diseases, especially in rheumatoid arthritis.

Evening primrose oil is found to be a rich source of essential fatty acid known as gamma-linolenic acid ( GLA) which has a number of therapeutic uses.

Evening primrose oil is used from ancient times as a part of folk medicine in the treatment of a number of skin disorders such as eczema, psoriasis, and acne.

It has many other health benefits too, such as is used in treatment of rheumatoid arthritis, osteoporosis (weak bones), neurodermatitis (itching disorder), attention deficit- hyperactivity disorder (ADHD), obesity, weight loss and number of gastrointestinal problems(such as ulcerative colitis, irritable in gastrointestinal tract, peptic ulcers).

The oil is also found to be effective in alleviating symptoms of syndromes like Raynaud’s syndrome (blood vessel disorder), multiple sclerosis (disease of the central nervous system), Sjogren’s syndrome (a chronic autoimmune disease), cancer, etc.

Evening primrose oil is also used as a dietary source in food and found use in cosmetic and soap industry.

Therefore due to its various health benefits, it was classified as a “dietary supplement” under the Dietary Supplement Health and Education Act of 1994.

What does Evening Primrose Oil contain?

Evening primrose oil is produced from seeds of evening primrose oil plant that is obtained by cold pressing using screw presses or extracted using solvent hexane followed by refining process of the crude extract.

The constituents of evening primrose oil are separated and identified using gas chromatography spectrometry or high performance liquid chromatography methods.

The crude extract of evening primrose oil is found to have maximum contents of antioxidants such as tocopherols which usually get washed away in the process of refining.

Therefore mostly vitamin E or other antioxidants are added to the final product to increase its oxidative stability before packaging.

Evening primrose oil is an excellent source of polyunsaturated omega-6 fatty acids that is made up of 2-15% gamma-linolenic acid (GLA) and 70% linolenic acid (LA) and smaller amount of oleic acid, palmitic acid stearic acid.

So when evening primrose oil is consumed, the later portion containing 70% of linolenic acid is being converted into GLA in our body, which plays an important role in maintaining joint structure and its function.

These gamma-linolenic acid is reported to suppress inflammatory responses which are directly related to inflammatory diseases.

But the scientist has shown some factors such as aging, nutritional deficiencies, viral infections and other health diseases that can affect the production of GLA in body and therefore there is a need of supplementary diet to supply the adequate quantity of GLA in body, especially during the arthritic condition.

A comparison study carried was out in between evening primrose oil and borage oil ( also containing GLA), and was found that the biological activity of GLA found in evening primrose oil was much better than that found in borage oil.

And the reason behind this mechanism was explained in vitro studies which says that the hydrolysis of triglyceride moieties present in GLA in evening primrose oil was much faster (80%) as those compared with those found in borage oil (20%).

6 Benefits of Evening Primrose Oil In Rheumatoid Arthritis

Evening primrose oil has gamma linoleic acid which contributes to its anti-inflammatory effect. Here are a few ways in which evening primrose oil can benefit in rheumatoid arthritis.

1. Various compounds in evening primrose oil help in reducing inflammation

Diets rich in omega 6 fatty acids like arachidonic acid can cause formation of pro-inflammatory mediators like 2 series prostaglandins and 4 series leukotrienes.

NSAIDs prescribed in rheumatoid arthritis inhibit the activity of inflammatory enzyme COX and decrease the production of 2 series prostaglandins.

However, the activity of LOX enzyme remains intact which increases the inflammation.

A diet rich in evening primrose oil raises the level of dihomo gamma linoleic acid which leads to the production of 1 series prostaglandins.

These do not cause much inflammation. DGLA blocks the formation of leukotrienes.

Additionally, it inhibits the activity of 2 series prostaglandins and 4 series leukotrienes.

An animal study also proves that dietary supplementation with evening primrose oil reduces inflammation, oxidative stress, inhibits the activity of inflammatory mediators and reduces stimulation of immune cells.

Study in humans shows that EPO (evening primrose oil) supplementation increases the level of dihomo gamma linoleic acid which can contribute to the anti-inflammatory effect.

Animal study shows that long chain fatty acids present in evening primrose oil exert anti-inflammatory effect.

A decrease in nitric oxide concentration, inhibition of nitric oxide synthase enzyme, inhibition of inflammatory mediators like 2 series prostaglandin, thromboxane, tumor necrosis factor, and interleukin are few of the mechanisms involved in their anti-inflammatory effect.

Sterols or steroid alcohols present in evening primrose oil also contribute to the anti-inflammatory effect.

They inhibit release pro-inflammatory mediators by inhibiting nitric oxide synthase and cyclooxygenase 2.

Evening primrose oil supplementation in diet reduces activation of immune cells-lymphocytes and inhibits production of inflammatory agents.

This is of relevance in treatment of rheumatoid arthritis and other inflammatory and autoimmune conditions.

What does this mean? GLA present in evening primrose oil gets converted to DGLA in the body which produces anti-inflammatory effect. Other compounds found in evening primrose oil such as sterols and esters are also responsible for its anti-inflammatory effect.

2. Evening primrose oil exerts antioxidant effect in rheumatoid arthritis

Rheumatoid arthritis is characterised by production of damaging reactive oxygen species.

These free radicals are produced by nitric oxide present in cells of joint tissue.

Inflammatory mediators support the production of nitric oxide by increasing the level of enzyme nitric oxide synthase.

Nitric oxide further aggravates inflammation by causing bone resorption. Painkillers like aspirin and steroids inhibit the activity of nitric oxide synthase.

A study investigating the composition of evening primrose oil has identified 3 antioxidants in EPO: betulinic, morolic, and oleanolic acid.

These compounds had potent radical scavenging properties (free radicals are compounds that cause oxidative damage) and also inhibited the activity of inflammatory enzyme COX-2.

Researchers conducted a study where they investigated the effect of evening primrose oil supplementation on antioxidant status in rheumatoid arthritis.

Individuals were assigned to 3 groups:
• Group 1: received only standard rheumatologic therapy
• Group 2: received concentrated fish oil
• Group 3: received concentrated fish oil and evening primrose oil

There were no changes in oxidative stress parameters in group 1.

However, in group 2 and 3 improvement in antioxidant enzyme levels and decrease in oxidative stress was observed.

Researchers stated that intake of fish oil and evening primrose oil can help reduce inflammation and disease activity by raising antioxidant enzymes.

What does this mean? Evening primrose oil supplementation improves antioxidant status in individuals suffering from rheumatoid arthritis and reduces oxidative stress.

3. Evening primrose oil supplementation reduces inflammation in Rheumatoid Arthritis

Brzeski et. al conducted a study where individuals suffering from rheumatoid arthritis and having gastric erosions as a side effect of non steroidal anti-inflammatory drugs, were treated with either evening primrose oil (6g/day) or olive oil.

3 patients in each group reduced dose of painkillers. 3 month treatment with evening primrose oil reduced morning stiffness.

Cameron et. al conducted a review study identifying various herbal therapies for rheumatoid arthritis.

Gamma-linoleic acid and evening primrose oil were identified as potential therapeutic agents and evidence showed that they improved joint function and reduced pain.

However, an increased number of side effects were reported in comparison to placebo.

A clinical trial was conducted where 18 patients with rheumatoid arthritis were treated with 10 ml olive oil or evening primrose oil for 12 weeks.

A decrease in prostaglandin levels and thromboxane levels both of which aggravate inflammation. However, no significant improvement was observed in any group.

Similar results have been proven by Hansen et. al where evening primrose oil supplementation brought about a difference in biochemical parameters but not in disease severity.

What does this mean? Human studies report mixed effects of EPO supplementation in humans. However a reduction in inflammatory parameters was reported by most studies. Some studies do indicate reduction in pain.

4. Evening primrose oil can reduce dependence on painkillers

An animal study investigated the effect of evening primrose oil in combination with aspirin and celecoxib, medications prescribed to deal with arthritic pain.

Evening primrose oil administration reduced levels of inflammatory mediators and restored antioxidant defences.

Evening primrose oil administration reduced the swelling in joint tissues and also reduced infiltration of immune cells in the joint tissues which would otherwise aggravate inflammation.

This effect was enhanced in by concurrent administration of aspirin and celecoxib.

Researchers concluded that evening primrose oil with medications prescribed for arthritis can reduce the progression of arthritis better.

Non steroidal anti-inflammatory drugs help in reducing pain and inflammation by inhibiting the activity of inflammatory enzyme, COX.

However some of them do not inhibit the activity of inflammatory enzyme, LOX which leads to production of other inflammatory mediators called leucotrienes.

GLA leads to series 1 prostaglandins which are less inflammatory and inhibits production of leukotrienes.

EPA found in fish oil also reduces inflammation.

A study was conducted where individuals were treated with 540mg GLA as evening primrose oil, 15 patients 240 mg EPA and 450 mg GLA/day (EPO/fish oil) and some were treated with placebo.

12 months treatment reduced the requirement of NSAIDs in GLA and GLA/EPA group. But despite the decrease in use of NSAIDS, the measure of disease activity did not reduce. In other words GLA and EPA brought about symptomatic improvement but did not treat the disease.

What does this mean? Research shows that evening primrose oil has a synergistic effect with painkillers like aspirin and celecoxib. Evening primrose oil supplementation can reduce dependence on NSAIDs and provide symptomatic relief in rheumatoid arthritis.

5. Evening primrose oil reduces side effects of NSAIDs

In animal model of gastric erosions caused by NSAIDs , evening primrose oil supplementation strongly inhibited the formation of gastric ulcers and protected gastric mucosa from irritation and inflammation.

Prichard et. al conducted a similar study in humans where they found that evening primrose oil supplementation did not protect from gastric damage caused by aspirin but reduced recurrence of peptic ulcer.

Medicines prescribed to treat arthritic pain and inflammation selectively inhibit COX enzyme.

An increased risk of a cardiovascular event is associated with these medications.

Co-administration of evening primrose oil with celecoxib (a medicine prescribed for arthritis) reduces the rise of blood pressure and clot formation caused by celecoxib administration.

What does this mean? Animal studies show that evening primrose oil can reduce gastric erosions and cardiovascular risk associated with painkillers and anti-arthritic drugs.

6. Evening primrose oil can help in complications of rheumatoid arthritis

Individuals suffering from rheumatoid arthritis were treated with 20 ml evening primrose oil or olive oil for 12 weeks and changes in fatty acids in blood was observed.

The treatment brought a decrease in oleic acid, eicosapentaenoic acid, and apolipoprotein B and there was an increase in levels of linoleic acid, gamma-linolenic acid, dihomo-gamma-linolenic acid, and arachidonic acid.

Decrease in apolipoprotein B indicates decrease in bad cholesterol levels and increase in linoleic acid and gamma linoleic acid indicates anti-inflammatory activity.

However decrease in eicosapentaenoic acid and increase in arachidonic acid is indicative of possible rise in inflammation.

Animal model of atherosclerosis (formation of plaque in blood vessels) and hyperlipidemia (elevated levels of cholesterol) was developed to understand the effect of evening primrose oil on these conditions.

Evening primrose oil supplementation reduced the lipid peroxidation, a marker of oxidative damage and raised the level of antioxidant enzymes.

Overall evening primrose oil reduced oxidative stress in these conditions.

Research shows that EPO reduces cholesterol level by facilitating excretion of cholesterol from the body.

Sjogren’s syndrome is a complication associated with rheumatoid arthritis. It is characterised by dry eyes and dry mouth.

Evening primrose oil supplementation is found to reduce inflammation and bring about slight improvement in ocular (eye) status in Sjogren’s syndrome.

Rheumatoid arthritis increases the risk of Raynaud’s phenomenon. This is characterised by reduced blood flow in cold conditions and emotional stress.

Treatment with evening primrose oil (12 capsules a day) brought about reduction in number of attacks, severity of attacks and coldness in those receiving the treatment.

What does this mean? Evening primrose oil can benefit in rheumatoid arthritis associated risks such as high cholesterol, atherosclerosis. Sjogren’s syndrome, Raynaud’ phenomenon etc.

How to use Evening primrose oil in food

Evening primrose oil is taken as a dietary supplement as it is a rich source of essential fatty acid, GLA as these fatty acids are not produced by body and has to be obtained from external source.

As they are good plant source of GLA, Native Americans normally incorporate its seeds, leaves and roots in diet to get its health benefits.

  • Roots are boiled and eaten just like potato pieces.
  • Young leaves of EPO are boiled and eaten as green vegetables.
  • The shoots are consumed raw like salad.
  • The roots are chewed and used to muscles to improve strength.
  • Tea made from plant parts is used as a stimulant for laziness and obesity.
  • A hot poultice is used to treat piles, boils, and bruises.

Otherwise, they are usually recommended by your health experts, if your body is found to be deficient in essential fatty acids.

Dosage of Evening Primrose Oil In Rheumatoid Arthritis

Evening Primrose Oil is available in capsule form or as an oil. You have to store evening primrose oil in refrigerator and protect from direct sun rays to avoid from becoming rancid.

Generally high-quality oil are available in the light-resistant container, certified as organic by reputed third party.

Evening primrose oil is available as oil and capsules. EPO should be standardized to contain 8% gamma-linolenic acid.

For most of the ailments, EPO can be taken in dosage of 1000 milligrams for 3 times in a day which provides around 250 milligrams of GLA in a day.

Average studies recommend taking 6g of evening primrose oil a day which provides 540mg GLA.

It is advisable to consult a doctor before taking evening primrose oil supplements to avoid allergic reactions and drug interactions.


Evening primrose oil is generally considered safe when taken in recommended dosage.

But reports have shown that evening primrose oil can cause some mild side effects such as nausea, stomach pain, and headache in some people.

And more stomach problems such as loose stools are reported with high dose intake. Pregnant and breastfeeding women are also advice to use evening primrose oil only after proper medical advice.

GLA present in evening primrose oil is found to increase the risk of bleeding in patients who are administered with anticoagulant drugs (blood thinners) such as aspirin, warfarin and clopidogrel and anti-depressants drugs.

It is also reported to lower the blood pressure in patients suffering already with high pressure problem.

Long term use of evening primrose oil can cause serious side effects.

Evening primrose oil can have drug interactions with blood-thinning medicines, blood pressure medicines, antidepressants and medicines used to treat seizures.


Gamma-linoleic acid present in evening primrose oil is the prime reason for its anti-inflammatory action.

Sterols and esters present in the oil also show anti-inflammatory and antioxidant properties.

Clinical studies investigating the role of evening primrose oil in rheumatoid arthritis have shown a moderate decrease in pain and observable reduction in inflammatory parameters.

Evening primrose oil can reduce dependence on NSAIDs and side effects associated with.

Additionally, evening primrose oil may ameliorate complications associated with rheumatoid arthritis.

Evening primrose oil can be a safe adjunct therapy for rheumatoid arthritis.

However, if you are taking aspirin or other blood thinners, please consult a doctor before taking evening primrose oil.

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.