My CTX did not go up with Tymlos. Only my P1NP went up, which is what we wanted. Tymlos stimulates osteoblasts which create new bone.

Reclast is stronger; after all, you are getting an annual infusion vs. taking a pill. But... it's an infusion. Some people have had bad reactions; others, no issues. If you have a bad reaction, there is no way to undo an infusion. Some people don't want to risk it.

I think this all depends on where you are when Tymlos is done. If you're well into osteopenia range, then maybe Fosamax is simpler. If you still need to build more bone, then Reclast (or Evenity) might be needed.