Borage oil is a plant-based oil extracted from the seeds of the borage plant (Borago officinalis), prized mainly for its unusually high concentration of gamma-linolenic acid, or GLA. At 18% to 26% GLA, borage oil contains roughly two to three times more of this fatty acid than evening primrose oil (7% to 10%) and slightly more than black currant seed oil (15% to 20%). GLA is an omega-6 fatty acid that the body converts into compounds involved in controlling inflammation, which is why borage oil appears in supplements marketed for skin conditions, joint pain, and general wellness.
How GLA Works in the Body
When you consume borage oil, the GLA it contains is quickly converted into a longer fatty acid called DGLA. Only a small fraction of DGLA turns into arachidonic acid, the compound often associated with promoting inflammation. Instead, most of it follows a different path: your body uses DGLA to produce a specific group of prostaglandins (hormone-like substances) that actually suppress inflammation, promote blood vessel relaxation, and lower blood pressure. A second pathway converts DGLA into another anti-inflammatory molecule called 15-HETrE.
This two-pronged mechanism is what makes GLA-rich oils interesting for inflammatory conditions. Rather than blocking inflammation after it starts (the way ibuprofen works), GLA shifts the balance of what your body produces in the first place, favoring anti-inflammatory signals over pro-inflammatory ones.
Skin Health and Eczema
Borage oil is most commonly marketed for skin conditions, especially eczema (atopic dermatitis). The logic is straightforward: people with eczema often have trouble converting dietary fats into GLA on their own, so supplementing directly could help restore the skin’s moisture barrier. In a study of healthy elderly adults, taking borage oil capsules providing either 360 or 720 mg of GLA per day for two months improved skin barrier function, reducing water loss through the skin by an average of 11%.
For eczema specifically, the evidence is less clear-cut. A double-blind trial of 160 patients taking 500 mg of borage oil daily for 24 weeks found that several individual symptoms improved compared to placebo, but the overall response did not reach statistical significance. However, when researchers looked at the subgroup of patients whose blood levels of DGLA actually increased (confirming they absorbed and metabolized the oil properly), the results were more favorable. No substance-related side effects were reported. The takeaway: borage oil is well tolerated for skin use, but it doesn’t work equally well for everyone, and absorption seems to matter.
Joint Pain and Rheumatoid Arthritis
GLA-rich oils, including borage oil, have been studied for rheumatoid arthritis symptoms. A Cochrane review pooling evidence from seven studies on GLA from borage, evening primrose, and black currant seed oils found moderate evidence of benefit. On a 100-point pain scale, GLA supplementation reduced pain by about 33 points more than placebo. Disability scores improved by roughly 16%. These are meaningful differences for people living with chronic joint inflammation.
The review did note a higher rate of mild adverse events in GLA groups (20%) compared to placebo (3%), though this difference was not statistically significant. Most side effects in GLA studies tend to be gastrointestinal: bloating, soft stools, or mild nausea.
Safety Concerns Worth Knowing
The borage plant naturally contains pyrrolizidine alkaloids, compounds that can damage the liver and, with prolonged exposure, potentially contribute to liver cirrhosis or cancer. The European Medicines Agency has flagged borage as one of several herbs with high pyrrolizidine alkaloid content. However, there’s an important distinction between the whole plant and the oil: because these alkaloids dissolve in water rather than fat, properly refined borage seed oil typically contains no detectable pyrrolizidine alkaloids. Oil-based extracts from plants that produce these toxins have been found to be free of them after standard processing. Still, choosing products from reputable manufacturers that test for these compounds is a reasonable precaution.
Seizure Risk
There is a documented association between borage oil and lowered seizure threshold. A case report published in the Journal of Medical Toxicology described status epilepticus (prolonged seizure activity) associated with borage oil ingestion. If you have epilepsy or any seizure disorder, borage oil is best avoided entirely until more is understood about this risk.
Blood-Thinning Effects
GLA inhibits leukotriene synthesis, which gives it both anti-inflammatory and anti-thrombotic (blood-thinning) properties. If you take anticoagulant or antiplatelet medications, this overlap could increase bleeding risk. The same mechanism that makes borage oil helpful for inflammation could become a liability when combined with blood thinners.
Dosage and Forms
Borage oil supplements come in soft gel capsules, with a typical capsule containing about 750 mg of borage oil and roughly 175 mg of GLA. Clinical studies have used daily GLA doses ranging from 360 mg (about two capsules) to 720 mg (about four capsules), depending on the condition being targeted. Skin barrier studies used the lower end of this range, while arthritis research tended toward higher doses.
Borage oil is also available as a liquid, sometimes used topically or added to foods. Regardless of form, it oxidizes quickly because of its high polyunsaturated fat content. Oxidation begins almost immediately upon exposure to air, light, and warmth. Store borage oil in a dark container, in the refrigerator, and use it before its expiration date. Rancid oil not only loses its therapeutic value but introduces harmful oxidation byproducts.
How It Compares to Evening Primrose Oil
Evening primrose oil is the most well-known GLA supplement, but borage oil delivers the same active compound more efficiently. You need roughly two to three times as many evening primrose capsules to match the GLA in a single borage oil capsule. Black currant seed oil falls in between, with 15% to 20% GLA. All three oils work through the same biological pathway, so the choice often comes down to cost per milligram of GLA and personal tolerance. Some people find borage oil capsules easier on the stomach, while others prefer the longer track record of evening primrose research.