Gamma-linolenic acid (GLA) is an omega-6 fatty acid that is found mostly in plant based oils such as: borage seed oil, evening primrose oil, and blackcurrant seed oil. Omega-6 fatty acids are considered essential fatty acids, as they are necessary for human health, but the body can’t make them and so you have to get them through food, or supplementation. Along with omega-3 fatty acids, omega-6 fatty acids play a crucial role in brain function, as well as normal growth, behaviour and development.


Also known as polyunsaturated fatty acids (PUFAs), they help stimulate skin and hair growth, maintain bone health, regulate metabolism, and maintain the reproductive system.


There are several different types of omega-6 fatty acids. which are largely found in vegetable oils in the form of linoleic acid (LA). The body converts linoleic acid to GLA and then to arachidonic acid (AA).


A healthy diet contains a balance of omega-3 and omega-6 fatty acids. Omega-3 fatty acids help reduce inflammation, and some omega-6 fatty acids tend to promote inflammation. Unfortunately many of our modern diets have displaced the ideal 1:1 ratio between these two essential fats, creating a position where many of us are now getting much more omega-6, and many researchers and clinicians increasingly believe that this higher ratio of omega-6 to omega-3 fatty acids has increased the rampant rise of inflammatory diseases in society. And so many of us will find we need a greater ratio of omega-3 (eg: a 2:1 ratio or even higher) to create healing and health.


So in order to get the balance right for yourself you will need to look at your whole diet, to see whether you are getting a much higher ratio of omega-6 and if that is the case, you’ll have to gauge how much omega-3 is needed to bring your diet  back into balance. It may be that you need to reduce your omega-6 intake as a way to restore the balance. However, each case should be assessed on its merits. You may need some professional help to work out the best strategy for you.


Not all omega-6 fatty acids behave the same. Linoleic acid and arachidonic acid (AA), in the wrong proportions, tend to be unhealthy because they can promote inflammation. GLA, on the other hand, may actually reduce inflammation.


GLA is converted to a substance called DGLA that fights inflammation. Having enough of certain nutrients in the body (including magnesium, zinc, and vitamins C, B3, and B6) helps promote the conversion of GLA to DGLA. However, many experts would still say that the science supporting the use of omega-3 fatty acids to reduce inflammation and prevent diseases is much stronger than that supporting the use of GLA/DGLA.


What does the research say….



GLA from evening primrose oil or other sources has a longstanding history of use for allergies. Interestingly women and children who are prone to allergies appear to have lower levels of GLA in breast milk and blood. However, there is still no solid scientific evidence that taking GLA helps reduce allergy symptoms, we mostly have anecdotal evidence, which does suggest this nutrient is helpful for some suffering with a variety of allergies. However, well conducted research studies are still needed.


Before you decide to try GLA for allergies, speak with your GP or health care professional to determine if it is safe for you. Then monitor your allergy symptoms closely for any signs of improvement or lack of improvement to determine its effectiveness for you. A good trial period is 3 months.


Attention deficit/hyperactivity disorder (ADHD)

Clinical studies suggest that children with ADHD have lower levels of essential fatty acids (EFAs), both omega-6s and omega-3s. EFAs are important to normal brain and behavioral function. Some studies suggest that taking fish oil (containing omega-3 fatty acids) may help reduce ADHD symptoms, though the studies have not always been well designed. Studies that used evening primrose oil alone have found it was no better than placebo at reducing symptoms.


Breast cancer

One study found that women with breast cancer who took GLA had a better response to tamoxifen (a drug used to treat estrogen sensitive breast cancer) than those who took only tamoxifen.

Evening primrose oil has also been used as a complementary treatment for some cancers. But again, there is not enough evidence to support such use.


Diabetic neuropathy

Some studies show that taking gamma linolenic acid (GLA) for 6 months or more may reduce symptoms of nerve pain in people with diabetic neuropathy. People who have good blood sugar control may find GLA more effective than those with poor blood sugar control.



Evidence is mixed as to whether evening primrose oil can help reduce symptoms of eczema. Some early studies found it did, but they were not well designed. Later studies that examined people who took evening primrose oil for 16 – 24 weeks found no improvement in symptoms.

There is however, some good research showing that evening primrose oil may be helpful in eczema or atopic dermatitis. Some studies suggest that supplements that contain gamma-linolenic acid (GLA), including evening primrose oil, may also be of some benefit to people with rheumatoid arthritis, which is an interesting development as there appears to be some connection between these two conditions.


High blood pressure (Hypertension)

There is some preliminary evidence that GLA may help reduce high blood pressure, either alone or in combination with the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), found in fish oil. In one study, men with borderline high blood pressure who took 6g of blackcurrant oil had a reduction in diastolic blood pressure compared to those who took placebo.

Another study examined people with intermittent claudication, pain in the legs while walking that is caused by blockages in the blood vessels. Those who took GLA combined with EPA had a reduction in systolic blood pressure compared to those who took placebo.


Menopausal symptoms

Evening primrose oil has gained most of its reputation as a way to treat hot flashes associated with menopause, but so far studies have been mixed with regards to its effectiveness, and yet there are many women who swear by it. If you want to try evening primrose oil for hot flashes and night sweats, we would recommend you discuss it with your health care professional or GP to see whether it is safe and right for you, given what has been previously said about the importance of the ratios.



Some evidence suggests that evening primrose oil may reduce breast pain and tenderness in people with cyclic mastalgia. It may also help reduce symptoms to a lesser extent in people with non-cyclic mastalgia. However, it does not seem to be effective for severe breast pain.



Some studies suggest that people who don’t get enough of some essential fatty acids (particularly EPA and GLA) are more likely to have bone loss than those with normal levels of these fatty acids. In a study of women over 65 with osteoporosis, those who took EPA and GLA supplements had less bone loss over 3 years than those who took placebo. Many of these women also experienced an increase in bone density.


Premenstrual syndrome (PMS)

Although many studies have found little or no effect, some women report relief of PMS symptoms when using GLA. The symptoms that seem to be helped the most are breast tenderness and feelings of depression, as well as irritability, swelling and bloating from fluid retention.


Rheumatoid arthritis

Studies are mixed as to whether evening primrose oil helps reduce symptoms of rheumatoid arthritis. Some preliminary evidence suggests evening primrose oil may reduce pain, swelling, and morning stiffness, but other studies have found no effect. When using GLA for arthritis symptoms, it may take 1 – 3 months to see any benefit. It is unlikely that evening primrose oil alone would help stop the progression of the disease, so joint damage could still occur.





Dietary Sources

GLA is found in the plant seed oils of evening primrose, blackcurrant, borage, and fungal oils. Spirulina (often called blue green algae) also contains GLA.


Available Forms

GLA supplements are made from evening primrose oil as well as blackcurrant seed and borage seed oils. Most GLA supplements are capsules containing oil. Evening primrose oil has been the most researched source of GLA and as a result the most used. Generally, high quality oil will be certified as organic by a reputable third party, packaged in light resistant containers, refrigerated, and marked with a use by date.


How to Take It

For your overall health, you should get a balance of omega-6 and omega-3 fatty acids. There is much disagreement in the nutrition field about what constitutes the proper ratio of omega-6 to omega-3 fatty acids in one’s diet. The average diet provides plenty of omega-6 fatty acids, so most people don’t need supplements. People with specific conditions, such as eczema or psoriasis, arthritis, diabetes, or breast tenderness (mastalgia), may want to ask their health care professional about taking omega-6 supplements. It is much more likely that omega-3 supplementation is needed, especially given the rise in brain development deficiencies, behavourial disorders and inflammatory conditions.



Also see: The Essentiality of Fats