Gamma Linolenic Acid

GLA is converted in the body to dihomo-gamma-linolenic acid (DGLA), which is the precursor for series-1 prostaglandins (PGE1), considered anti-inflammatory eicosanoids. DGLA also competes with arachidonic acid for enzymes that produce inflammatory mediators, potentially shifting the balance toward less inflammatory products. Research suggests endogenous GLA production via delta-6 desaturase can be impaired by aging, diabetes, atopic conditions, certain genetic variants, and dietary factors. In these conditions, dietary GLA supplementation can help maintain adequate downstream anti-inflammatory eicosanoid production. This is the rationale for using GLA in conditions involving inflammation including arthritis, atopic dermatitis, and certain skin conditions. Clinical evidence varies by indication. GLA has the strongest evidence for rheumatoid arthritis, where multiple trials show reductions in joint symptoms. For atopic dermatitis, evidence is mixed. For diabetic neuropathy, some trials show benefit, possibly because diabetes impairs delta-6 desaturase function. GLA effects on women's health concerns (PMS, mastalgia) have limited rigorous support.

Typical doses are 240-720 mg of GLA per day. Higher doses (1-3 grams of GLA per day) have been used in clinical research for inflammatory conditions like rheumatoid arthritis. There is no established RDA.

Take GLA-containing oils with food to improve absorption (they are fat-soluble) and reduce gastrointestinal upset. Splitting daily doses (morning and evening) may help maintain steady GLA levels. Therapeutic effects on inflammatory conditions typically require 4-12 weeks of consistent use to assess.

GLA-containing oils are generally well tolerated. Common side effects include mild gastrointestinal upset, soft stools, burping, and headache. GLA may modestly lower seizure threshold. The specific oil source (borage, evening primrose, etc.) carries its own safety considerations; borage oil requires PA-free certification due to potentially hepatotoxic pyrrolizidine alkaloids in raw borage.

GLA-rich oils may have mild antiplatelet effects and could theoretically increase bleeding risk with anticoagulants or antiplatelet drugs. They may lower seizure threshold and should be used cautiously by people with epilepsy or taking anticonvulsants, and may interact unfavorably with phenothiazine antipsychotics.