Having an underactive thyroid and taking Synthroid (levothyroxine) will not affect your bone health unless you are taking too much (since too much Synthroid can contribute to bone loss).
Ukuba nedlala letharoyidi elisebenza kancinane nokusebenzisa iSynthroid (levothyroxine) akuyichaphazeli impilo yamathambo akho ngaphandle kokuba ulisebenzisa ngokugqithisileyo eli yeza (nanjengoko iSynthroid eninzi inegalelo ekupheleni kwamathambo).