Dihomo-gamma-linolenic acid

Dihomo-gamma-linolenic acid (DGLA) is a 20-carbon ω-6 fatty acid. In physiological literature, it is given the name 20:3(n-6). Chemically, DGLA is a carboxylic acid with a 20-carbon chain and three cis double bonds; the first double bond is located at the sixth carbon from the omega end. DGLA is the elongation product of γ-linolenic acid [18:3(n-6)].

Biological effects
The eicosanoid metabolites of DGLA are:
 * Series-1 thromboxanes (thromboxanes with 1 double-bond), via the COX-1 and COX-2 pathways.
 * Series-1 prostanoids, via the COX-1 and COX-2 pathways.
 * A 15-hydroxyl derivative that blocks the transformation of arachidonic acid to leukotrienes.

All of these effects are anti-inflammatory. This is in marked contrast with the analogous metabolites of arachidonic acid (AA) which are the series-2 thromboxanes and prostanoids and the series-4 leukotrienes. In addition to yielding anti-inflammatory eicosanoids, DGLA competes with AA for COX and lipoxygenase, inhibiting the production of AA's eicosanoids.

Taken orally in a small study, DGLA produced antithrombotic effects. Supplementing dietary GLA increases serum DGLA without increasing serum AA.