Antioxidant

Alpha-lipoic acid (ALA) is a sulfur-containing mitochondrial cofactor, used as a racemic drug for the pain and pins-and-needles of diabetic nerve damage. Meta-analyses of randomised trials support it for diabetic neuropathy symptoms. Its effects on weight and blood sugar are real but small. Supplements come as the racemic mix, as pure R-ALA, or as Na-R-ALA, a sodium salt of R-ALA made to absorb better.

Coenzyme Q10 (CoQ10) is part of the mitochondrial energy chain and one of the most widely used supplements. Its best evidence is in chronic heart failure. There, the Q-SYMBIO trial found fewer major cardiovascular events and deaths over two years. For statin muscle pain, migraine and blood pressure, the results are mixed or modest.

PQQ (pyrroloquinoline quinone) is a redox cofactor first found in bacteria. Mammals do not make it but take in trace amounts from food. In cells it switches on mitochondrial biogenesis through the PGC-1α pathway. In humans, small 12-week trials of PQQ disodium salt reported better memory and attention scores.

Ubiquinol is the reduced, electron-carrying form of coenzyme-q10, sold as a better-absorbed version. One small study found it raised blood CoQ10 more than ubiquinone. A randomised crossover study in older adults found no significant difference. Its most notable trial is in multiple-system atrophy, where high doses improved a motor score.