Have been hypothyroid for 11 years now and all of that time I have been on 50mcg of Levothyroxine each day. My doctor tells me my thyroid is only slightly underactive. However, I regularly feel tired but get on with things. I put on weight and it was during a range of tests that they found I had an underactive thyroid. I've lost 1st 9lbs which I found quite easy to lose but I'm finding it very difficult to lose any more. My eyebrows have also really thinned. Would welcome any advice.