Endocrinologist, yes.

Dr. Keith McCormick is actually a chiropractor who became, from his own experience with osteoporosis, an expert on the subject. He does phone consultations. He also wrote a very popular book on the subject.
https://www.osteonaturals.com/about-osteonaturals
https://www.amazon.com/Great-Bones-Taking-Control-Osteoporosis/dp/B0BS8RJ2V3
There are many people here who have consulted with him. It does take some time to schedule with him - he's very busy. Initial consult is, I forget, $300? But then the follow-ups can be for as short as 15 minutes and are much cheaper (e.g. you want to review some lab tests, etc.)

Some people (like me) consult with him, but also use an endocrinologist to order bone scans and lab tests, prescribe meds, etc. Dr. McCormick cannot prescribe meds in NJ, NY, and CT; those states do not allow chiropractors to do so. The other 47 states, no problem. He is not one to push medication, but he does advise it depending on your condition (to "buy time", as he calls it.)