teriparatide affects your bones in two different ways depending on how often and how long you use it.
taking it in short bursts speeds up endochondral ossification, and it does this without needing growth hormone.
this works directly on the growth plates and secondary ossification centers. it increases signals like Ihh and PTHrp, which control how cartilage turns into bone. when PTH levels are high from outside sources, it makes the growth plate cells mature and die faster than normally.
normally, puberty (HPG axis ) controls bone development, but teriparatide mostly bypasses that and acts locally on the growth plate through things like Ihh, Runx2, and osterix.
so basically, your bones are likely maturing faster because of external PTH, not because of normal hormonal puberty