It is possible, Thyroid meds are funny, what works well for one does not work well for others, I was on (
Generic)
Levothyroxine for six months and my labs did not budge, then went to Synthroid (
brand Name) and had better sucess, my endo claimed that generics were not as consistant as name brand. Pharmacy said they are the same? So the change may have made a difference, some times the fillers they use can cause issues also.