Hi, @bayhorse. Four months after starting Tymlos, my rheumatologist had me test for P1NP, a marker for bone formation (osteoblast activity) to see if Tymlos was doing its job. It was -- my P1NP went from 59 (taken when I first met her) to 183. My DEXA a year later reflected that: improvement in my spine and hip. I'm now starting my second year of Tymlos, and my endocrinologist warned me that while the first year showed significant improvement, any improvement in my second year will be much smaller. (A chart on the Tymlos website shows that increases in BMD starts dropping the second year.) So it looks like you shouldn't be surprised about your second-year results.

My endocrinologist said she would use the markers, specifically the CTX, once I start a bisphosphonate, to make sure my bone resorption level is going back down to "normal" (Tymlos increases it, just as it increases bone formation). At least that is what I think she said. (I'm hoping others on this thread will weigh in on what they have learned.).

Both my rheumatologist and my endocrinologist are insistent I take one of the bisphosphonates after finishing Tymlos to preserve the new bone formed. My rheumatologist said that one of her patients didn't want to take a bisphosphonate afterward, and ended up losing all the new bone that had been created. (Which, if she was paying what I have had to pay for this drug, was a huge waste of money!)