Dr. Bruce Ames, professor of biochemistry and molecular biology at UC Berkeley, has highlighted two useful rejuvenation molecules: acetyl-carnitine (ALC) and lipoic acid (LA).
At age 86, and still conducting research (he takes these two compounds, perhaps others), Ames may be the most celebrated biochemist alive. He invented the famous Ames test of mutagenicity and has won of the National Medal of Science and Thomas Hunt Morgan Medal.
A proponent of the salutary effects of natural products in foods, Ames has demonstrated that ALC and LA, alone but especially in combination, dramatically reduce mitochondrial dysfunction, cognitive decline and other measures of aging in model organisms.
Ames, Bruce and Liu, Jiankang (2004). Delaying the Mitochondrial Decay of Aging with Acetylcarnitine. Ann. N.Y. Acad. Sci. 1033: 108–116.