Alpha-lipoic acid occurs naturally as a 50/50 mixture of R-lipoic acid (R-ALA) and S-lipoic acid (S-ALA). R-lipoic acid by itself functions as an essential cofactor for many enzymes involved in energy production.* It also has characteristics, including significant antioxidant effects, that contribute to liver, brain, nerve, and eye health.* Studies indicate that supplements containing only R-lipoic acid appear to be better absorbed than supplements containing both R-lipoic acid and S-lipoic acid, with results showing twice as much ALA appearing in the bloodstream after an oral dose of R-Lipoic acid.* Because R-Lipoic acid is the form best utilized by the body, Thorne provides R-lipoic acid bound to sodium, providing it in its most stable, absorbable form.*

Alpha-lipoic acid, also known as thioctic acid, was discovered in 1951 as a molecule that assists in acyl-group transfer and as a coenzyme in the Krebs Cycle. In the 1980s, the scientific community realized that alpha-lipoic acid is also a powerful antioxidant.* What sets ALA apart from other fatty acids is that it's an antioxidant in both fat- and water-soluble environments, and it's also an antioxidant in both its oxidized and reduced forms.* This is unlike vitamin C, for instance, which is a water-soluble antioxidant, as well as vitamin E, which is a fat-soluble antioxidant. ALA also increases intracellular glutathione and CoQ10 levels.* Its other mechanisms of action include promoting normal protein glycosylation and inhibiting the enzyme aldose reductase, which in turn inhibits conversion of glucose to sorbitol.*