Finasteride reduces the conversion of testosterone to dihydrotestosterone, preventing miniaturization of susceptible follicles
Vitamin B12 injections allow for quicker absorption into the body and you feel the effects (increased energy, focus, improved sleep) within 48 - 72 hours and the effects last for about 1 week.
Cerovecki, T., Bojanic, I., Brcic, L., Radic, B., Vukoja, I., Seiwerth, S., & Sikiric, P
Autoimmunity and oxidatively modified autoantigens
Athletes should verify any medication, supplement, peptide, or hormone-related treatment with their sport organization, medical provider, and anti-doping resources before use