Acetyl-L-Carnitine and ALA both are among the best things we can take. There is a wealth of info on Medline. One especially heartening one (that I can't lay my hands on right now of course) showed ALCAR to actually increase the cross sectional area of the nerve fibers and improve diabetic neuropathy by making the remaining nerves more efficient.

Here is a general clip from 12 years ago! Makes you wonder why it isn't a standard part of out treatment doesn't it!

1: Life Sci. 1994;54(17):1205-14.

Acetyl-L-carnitine affects aged brain receptorial system in rodents.

Castorina M, Ferraris L.

Institute for Research on Senescence, Sigma-Tau, Pomezia, Rome, Italy.

Acetyl-L-carnitine (ALCAR), the acetyl ester of carnitine, is regarded as a
compound of considerable interest because of its capacity to counteract several
physiological and pathological modifications typical of brain ageing processes.
In particular, it has been demonstrated that ALCAR can counteract the
age-dependent reduction of several receptors in the central nervous system of
rodents, such as the NMDA receptorial system, the Nerve Growth Factor (NGF)
receptors, those of glucocorticoids, neurotransmitters and others, thereby
enhancing the efficiency of synaptic transmission, which is considerably slowed
down by ageing. The present review thus postulates the importance of ALCAR
administration in preserving and/or facilitating the functionality of
carnitines, the concentrations of which are diminished in the brain of old
animals.

PMID: 8164502 [PubMed - indexed for MEDLINE]