Most thyroid problems are a result of autoimmunity. More specifically, when the body’s immune system becomes over-responsive, it begins to attack its own tissue. This condition is known as Hashimoto’s Thyroiditis. 

Over 95% of hypothyroid cases are in fact Hashimoto’s, however, the diagnosis is often missed because antibodies testing is not part of routine testing. Moreover, thyroid antibodies are continually in flux. Therefore, if testing was done at a time when antibodies happened to be in normal range, attention won't be drawn. For this reason, thyroid antibody testing should be to be repeated annually at the very least. 

Classic thyroid symptoms include:

It is important to note that many thyroid conditions have none of the above symptoms and can manifest in other ways. This is again why testing for thyroid antibodies is essential. The thyroid antibodies to test for are:

When thyroid hormones and / or antibodies test out of range, medication isn't the only option. Apart from side effects, taking medication sweeps the initial causes under the rug.