Under optimal conditions--
 

--which means no further damaging processes, sufficient oxygen and nutrients, and the like, the figure usually given for nerve regeneration is around a millimeter each day. This would apply to all regenerating nerves--the body generally doesn't concentrate its efforts on one nerve tract to the exclusion of all others, and then, when that tract is "restored", shift to the next one.

What this means is that a fiber that begins in the dorsal root ganglia and reaches down to the fingers or toes might take years to reach its destination, if it ever does. Many people have nerve regeneration that is patchy or incomplete. And seldom do the nerves take the exact same route to their afferents that they occupied before; along the way the nerve growth cones have to fight through and around connective tissue, muscle and the like, so I think the millimeter/day estimation is fairly optimistic.

There are certain nutrients that facilitate nerve repair.

methylB12 (which does cross into the spinal cord and CNS)
folate
P5P (activated pyridoxine B6)

fish oil to provide the lipids needed for cell membranes

Magnesium to facilitate lipid metabolism...

These are the basics. Mitochondrial support may help too...
acetyl carnitine
CoQ-10
R-lipoic acid

These three may aid the cells in the axons to provide more energy for the repair.

What about taurine?

"Taurine is an amino acid that can be made in your body from two other amino acids: cysteine and methionine...

"A facilitator for the passage of sodium, potassium and possibly calcium and magnesium ions into and out of cells."
http://www.drlwilson.com/Articles/TAURINE.HTM

"taurine can replace some of magnesium's functions when magnesium is deficient. . . Both nutrients exert sedative effects and lower the excitability of nerve cells."

http://www.studio41.co.nz/Community/...-of-magnesium/

I don't know if magnesium taurate is made with the right ratio (I take my Mg and Taurine separately).

There's not much research on humans yet, but there has been some success with rats.

"Studies have shown taurine can influence (and possibly reverse) defects in nerve blood flow, motor nerve conduction velocity, and nerve sensory thresholds in experimental diabetic neuropathic rats."

http://en.wikipedia.org/wiki/Taurine

It seems pretty safe from what I've read so I take it every day, esp. because I don't eat much meat, which causes a taurine deficiency.

P.S. It's good for cat eye health.

Humans should be able to make enough Taurine to get by normally.

But diabetics seem to have problems relating to low taurine specifically. Since it is made in the pancreas, there may be some link there.

Also extra taurine can be helpful for sluggish gallbladders, and to help reduce gall stones.

Cats are one of the few mammals who cannot synthesize taurine for themselves. They are dependent on the rodents they eat for it. This is why taurine is added to commerical cat foods.
I give extra taurine to my cats, mixed into their food, when I give "human" type food proteins to them. (Tuna in oil, for example). I have found that giving table food minus seasonings, leads to better health for them. And Oreo with her mast cell cancer does very well on Tuna in oil. (with Taurine added by me). The goal according to the Vet is to keep her from losing weight, and the Tuna does this very well. She also gets plenty of commerical cat foods too, including a new grain free kibble by Blue Buffalo.

I can't see taurine being a problem for humans, as a supplement. I've used it myself for gall bladder issues now and then, but I don't take it all the time.

Taurine and inositol are recommended supplements in some papers for diabetics.