Alpha-Lipoic Acid

•Observational— Approved in Germany for neuropathy; longevity case weaker

What it is

Alpha-lipoic acid (ALA) is a disulphide compound made in mitochondria, where it is a cofactor for the pyruvate dehydrogenase and alpha-KGDH complexes. As a supplement it acts as both a direct antioxidant and a regenerator of other antioxidants (vitamin C, vitamin E, glutathione).

What the evidence shows

• Diabetic peripheral neuropathy: largest evidence base; ~50% symptomatic improvement, used clinically in Europe (Germany has approved IV ALA).
• Glucose handling: small improvements in insulin sensitivity.
• Weight loss: small (~1.5 kg vs placebo over months).
• Cognitive aging: mixed signals.
• No human lifespan trials.

Forms

• R-ALA (natural enantiomer) is more bioavailable and active.
• S-ALA (the other half of racemic ALA) is less active.
• Best to buy R-ALA explicitly; "ALA" usually means racemic.

Cautions

• Mild hypoglycaemia risk in diabetics on insulin/sulfonylureas.
• Chronic high doses may deplete biotin.
• IV ALA has rare insulin-autoimmune syndrome (Asian populations).

Related entries

Mitochondrial dysfunction, Type 2 diabetes, GlyNAC.