Typically, a B12 shot is administered in the upper buttocks, but some nurses will also use the shoulder
(3) C.H.Chang et al (1985) The promoting effect of pentadecapeptide BPC 157 on tendon healing involves tendon outgrowth, cell survival, and cell migration Journal of Applied Physiology, 2011 Mar;110(3):774-80
Administered by Rita Dronsky, RN, with 20+ years of ICU and aesthetics experience
In particular, the initial burst of superoxide that cannot be eliminated efficiently due to the inactivity of SOD1 is promptly buffered by the induction of GSH synthesis resulting in protection against oxidative stress and cell death
The point is, we just dont know, and there's so much more research that needs to be done