Gamma-Linolenic Acid (GLA): Uses, Side Effects & More

Gamma-linolenic acid (GLA) is a type of omega-6 fatty acid that's in borage, primrose, and black currant seed oils.

In general, omega-6 fatty acids—like GLA—play an essential role in normal bodily functions.

GLA may have some anti-inflammatory effects, meaning it can help reduce inflammation that causes swelling, redness, and pain. It likely does this by blocking inflammatory pathways and decreasing the amounts of certain substances.

GLA may benefit people with certain medical conditions, such as autoimmune conditions like rheumatoid arthritis (RA).

Chronic (long-term) inflammation is the likely cause of symptoms in autoimmune conditions. In RA, an overactive immune system (the body's defense system) attacks parts of the body by mistake.

Interestingly, GLA may also promote inflammation. High amounts or long-term use of omega-6 fatty acids might cause more harm than good.

This article discusses what you should know about GLA—its potential uses, side effects, and interactions.

Gamma-Linolenic Acid Uses

As with many natural products, more extensive research is necessary.

People use GLA for various reasons, including to improve skin conditions and to fight inflammation.

Skin Conditions

Several studies have supported GLA-enriched supplements for skin conditions such as atopic dermatitis (eczema). GLA supplements may contain borage, primrose, or black currant seed oils.

However, one review questioned the actual effectiveness of GLA-enriched supplements. While a 2014 clinical trial suggested GLA from primrose oil may benefit children and adults with atopic dermatitis.

Due to mixed research results, additional high-quality, longer-term clinical trials with larger groups of people are necessary to better assess the effects of GLA-enriched supplements.

Rheumatoid Arthritis

Several studies have supported GLA-enriched supplements for rheumatoid arthritis. However, other studies suggest it's unclear if GLA-enriched supplements are effective for RA.

One study suggested people with RA might benefit from GLA derived from primrose oil, but in this study, GLA was also combined with omega-3 fatty acids.

High-quality, longer-term clinical trials with a larger group of people are necessary to better evaluate the effects of GLA-enriched supplements on RA.

Diabetic Neuropathy

A small clinical trial suggested GLA might relieve neuropathy symptoms (nerve pain) from diabetes (high blood sugar caused by a problem in the way the body regulates and uses glucose for energy).

However, higher-quality, longer-term, and larger studies are necessary better to evaluate GLA's effects and safety for diabetic neuropathy.

What Are the Side Effects of Gamma-Linolenic Acid?

As with many medications and natural products, side effects are possible with GLA.

Common Side Effects

Common mild side effects may include:

• Acid reflux
• Diarrhea
• Itchiness
• Nausea
• Problems with concentration (focus)
• Stomach pain
• Tiredness

Severe Side Effects

One study showed no serious side effects with GLA from primrose oil.

However, a severe allergic reaction is a serious side effect possible with any medication, including supplements.

If you're having a severe allergic reaction to GLA or any of the plants it may be derived from, you will experience symptoms such as breathing difficulties, itchiness, and rash.

Omega-6 fatty acids may reduce inflammation, but it can also promote inflammation at high doses or with long-term use. This might result in heart-related effects.

Until more high-quality and long-term clinical trials are available, consider using GLA for only a short period.

Call 911 and get medical help immediately if you have a severe allergic reaction or any of your symptoms feel life-threatening.

Precautions

A healthcare provider may advise against using GLA if any of the following applies to you:

Severe allergic reaction: If you have or have had in the past a severe allergic reaction to GLA, the plants it is derived from, or any of its components (ingredients or parts), you should not take this medication.

Pregnancy and breastfeeding: Everyone—including pregnant and breastfeeding people—likely gets omega-6 fatty acids in 5% to 10% of total calories through their diet. Primrose oil, which is abundant in GLA, might be safe while pregnant or breastfeeding.

High amounts of omega-6 fatty acids may negatively affect an unborn fetus or nursing infant. Moreover, borage seed oil is rich in GLA but may also contain certain chemicals that might be toxic to the liver and lungs. And these chemicals may also be present in breast milk. Contact a healthcare provider to discuss the benefits and risks before taking GLA.

Children: Children have participated in GLA-related studies, but many labels of GLA-containing products usually are for adults, not children. Talk with their healthcare provider if you are considering GLA for your child.

Older adults over 65 years: Older adults participated in some GLA-related clinical trials, but these studies were small. In addition, some older adults are more likely to have medication side effects. For this reason, take GLA with caution.

Heart-related conditions: High amounts or long-term use of omega-6 fatty acids might negatively affect the heart. A healthcare provider may want to closely monitor you if you already have a heart-related condition, such as heart disease.

Dosage: How Much Should I Take Gamma-Linolenic Acid?

While there are some studies on GLA in humans, additional high-quality clinical trials are still necessary.

This is due to several reasons, including that many of the available studies are small in size, and dosages differ in each study.

For these reasons, there are no guidelines on the appropriate dosage to take GLA for any condition.

If you take GLA, follow a healthcare provider's recommendations or label instructions.

What Happens If I Take Too Much Gamma-Linolenic Acid?

There is little information about GLA toxicity and overdoses in humans, however, high doses or long-term use of omega-6 fatty acids might negatively affect the heart.

If you suspect you're experiencing life-threatening side effects, seek immediate medical attention.

Interactions

There is limited information about possible medication interactions with omega-6 fatty acids.

However, omega-6 fatty acids found in GLA may affect inflammation pathways and substances in your body. These are the likely causes of symptoms and problems in several autoimmune diseases.

For these reasons, GLA might interact with other medications that affect inflammation or the immune system.

For example, GLA might interact with nonsteroidal anti-inflammatory drugs (NSAIDs), such as Motrin or Advil (ibuprofen). GLA might also have additive effects (harmful increased effects of using more one drug with similar outcomes) with certain drugs, including biologics and other medications that tamp down the immune system, such as Humira (adalimumab).

With high doses or long-term use, omega-6 fatty acids may also negatively affect the heart and blood vessels. Therefore, GLA might interfere with the benefit from heart-related medications, such as blood pressure medications—like Zestril (lisinopril)—and blood thinners—like Jantoven (warfarin).

It is essential to carefully read a supplement's ingredients list and nutrition facts panel to learn which ingredients are present and how much of each ingredient is included. Please review this supplement label with a healthcare provider to discuss potential interactions with foods, other supplements, and medications. 

How to Store Gamma-Linolenic Acid

Carefully read the directions and packaging label on the container. Keep your medications tightly closed and out of the reach and sight of children and pets, ideally locked in a cabinet or closet. Store in a cool and dry place.

Discard after one year or as indicated on the packaging.

Avoid putting unused and expired medicines down the drain or in the toilet. Visit the FDA website to learn where and how to discard of all unused and expired medicines. You may also find disposal boxes in your area.

Ask a pharmacist or healthcare provider any questions you may have regarding disposing of your medications or supplements.

Similar Supplements

GLA may have potential uses for skin conditions, rheumatoid arthritis (RA), and nerve pain from high blood sugar. Other potentially similar supplements include:

• Probiotics: Probiotics—particularly Lactobacillus rhamnosus GG in infants or pregnant parents—may help relieve atopic dermatitis (eczema) symptoms, especially when combined with standard medications.
• Omega-3 fatty acids: Omega-3 fatty acids, as well as the traditional Chinese medicine thunder god vine herb (Tripterygium wilfordii), may improve some RA symptoms.
• Alpha-lipoic acid (ALA): Alpha-lipoic acid is also known as thioctic acid. It's a naturally occurring antioxidant made in the body to attack free radicals, which are unstable molecules created during normal cell division that interfere with body processes and properties, like DNA, causing damage. ALA may also help relieve some symptoms of diabetic neuropathy, which is nerve pain from diabetes (high blood sugar).

Don't combine multiple natural products until you first talk with a registered dietitian, healthcare provider, or pharmacist. Inquiring about adverse side effects can help you avoid possible interactions and side effects and ensure you're giving these supplements a fair trial at appropriate doses.

Sources of Gamma-Linolenic Acid & What to Look For

There are several different sources of GLA.

Food Sources of Gamma-Linolenic Acid

In general, omega-6 fatty acids—like GLA—are found in various plants and seed oils, such as borage, primrose, and black currant seed oils.

Gamma-Linolenic Acid Supplements

GLA is likely available as GLA-enriched supplements, such as borage, primrose, and black currant seed oils. GLA-containing supplements might also be combined with other ingredients.

GLA-enriched supplements are generally available in several forms, including capsules and tablets.

These supplements might also be available in the following formats:

• Chewables
• Liquids
• Powder

Vegetarian and vegan options might also be available.

What may work for you will depend on your preferences and what you hope to get regarding effects. Each product will work a bit differently, depending on the form.

Following a healthcare provider's recommendations or label directions is essential.

Summary

GLA is an omega-6 fatty acid in borage, primrose, and black currant seed oils. It might have some benefit in treating atopic dermatitis (eczema), rheumatoid arthritis (RA), and diabetic neuropathy (nerve pain from high blood sugar). But, similar to many medications and natural products, side effects and medication interactions are still possible.

Additional higher-quality, longer-term, and larger clinical trials are still necessary to better evaluate the effectiveness and safety of GLA. Before taking GLA, involve a registered dietitian, pharmacist, or healthcare provider in your decision.