I think Vitamin B12 in the form of Cianocobalamine works quite well. Here in Spain
you can get it at the pharmacy as a drug called "Trofalgon" designed for lactose
intolerant babies. I am basing the idea it works on the grounds that the drug is a
banned supstance in competitive sports here, under the catergory of Anabolics.
If it didnt work why would they ban it ? I have no actual empiric evidence it work though.