I did 3,000 units starting at a D3 level of 50. I don't know how low you are but if in the teens or low 20's you probably need more than 3,000. I know the doctor gave my daughter 10,000 units when her level was in the teens, and she was not on Tymlos of course (teenager then).

My doctor does not do bone marker tests and says they do not tell the whole story of what is going on in bone. McCormick, the author of "Great Bones" suggests that treatment be guided by them. There is disagreement on this as you can see. The P1NP measures bone growth and the CTX measures bone resorption. Ideally you would have higher P1NP and lower CTX but most treatment protocols right now don't achieve that- Evenity might come close, yet to be seen. Tymlos and Forteo raise both and I believe Prolia, Fosamax, Reclast lower both. Dr. Ben Leder has a good video on YouTube entitled "Combining and Sequential Approaches to Osteoporosis if you are interested.