PUFAs are essential nutrients that show distinct deficiency syndromes when not present in adequate amounts in the diet. Methyl GLA is an esterified version of the free acid which is less water soluble but more amenable for the formulation of GLA-containing diets and dietary supplements. GLA is an ω-6 fatty acid which can be elongated to arachidonic acid for endogenous eicosanoid synthesis. It is a weak LTB4 receptor antagonist, inhibiting [3H]-LTB4 binding to porcine neutrophil membranes with a Ki of 1 µM. GLA produces 53% inhibition at a 1 mg/kg dose in an in vivo model of LTB4-induced bronchoconstriction.