@felicitypevancy - Dr. McCormick outlines how to use bone markers. Check it out. He uses CTX (indicator of bone breakdown) and P1NP (indicator of bone building) before treatment. Then after 3 months on meds repeats P1NP to see if it’s working. There are specific things to do and the timing of when you are tested that are important to help values be valid and comparable. Don't take my word for it - get his book , GREAT BONES, and read for yourself. Or listen to a podcast he did with Margie Bissinger , I believe in January where he discussed this. Good luck!!