Is it ok to use kaminomoto hair growth accelerator 2 on my beard as well?

Hard to say: i read the ingredient list, does not appear to cause harm to the skin in any way, but since it is only recommended for your scalp my conservative answer would be: don't do that. Contains: Alcohol, H2O, rosemary extract, capsicum frutescens, glycerine, menthol, sophora radix (kujin extract), allantoin, panthenol, pyridoxine HCl, isodonis japonicus (enmeiso extract), glycyrrhetinic acid, hinoki, etc