http://www.medications.com/effect/view/24205 I started synthroid about 6 months ago and I am unhappy. I complained to my OB about my lack on sex drive. He tested my thryroid and said it was the cause. I have always struggled w/ my weight but had it under control. Since I started a low dose of synt Sat, 09 Feb 2008 09:36:01 -0500 http://www.medications.com/effect/view/24205?item=4705 Hair loss is a common side effect when starting this medication (synthroid). Some people also gain weight on it (it's rare-but does happen). I have underactive, and no sex drive at all. Ask your ob to run tests on you for your sex glands. These are testost http://www.medications.com/effect/view/24205?item=4705