 [ Symptoms ] is it possible for a therapeutic overdose of synthroid to cause weightloss  i have been on synthroidlevothyroxine for years over the past year i lost on purpose 45 pounds now i cannot maintain my weight i have increased my calories by half and still am losing weight could this be because my synthroid dose is no longer appropriate for my weight [ Disease ] taking any dosage over the recommended by your doctor can cause serious medical problems these meds are not weight loss pills even though it may be tempting to use them in such a way better safe than sorry