R-ALA, formally α-lipoic acid, is (through well-understood physiology) a cofactor for some enzymes, notably the pyruvate dehydrogenase complex, the 2-oxoglutarate dehydrogenase complex, branched-chain oxoacid dehydrogenase complex and the acetoin dehydrogenase complex.

The link above asserts, with no evidence, that some OTC forms of R-ALA, taken by mouth, are helpful for neuropathy but others are not. For example, one commercially available form of R-ALA is rejected on the grounds that "it is not 100% sodium stabilized". This sounds very scientific but is meaningless.

If people with neuropathy choose to self-medicate with R-ALA taken by mouth that is their call. However, they should do so in the knowledge that there is no good evidence that it will help.

These issues are discussed in more detail here Lipoic Acid | Linus Pauling Institute | Oregon State University.