Low magnesium can cause constipation. Try CALM its a powered magnesium citrate you make a warm drink with. It works great . Drink it before bed. Just the tsh test for thyroid is not anough. Get your t3 and t4 tested. Saliva tests are better.MY tsh tests are always wrong. I have had doctors say I don't need so much hormone and they really scewed me up. I thank God I found a doctor who goes by my symptoms also.Is your temp. low. That can mean low thyroid.