I assume it would be very uncommon to have permanent thyroid shut down, typically we see problems for 4-8 weeks...but with thyroid abnormalities, that can seem like a long time and the medical risks are increased compared to altering some of the other hormones. There was one person I knew who had to stay on thyroid medicine after using high doses without medical monitoring. Again, the point is that it can be dangerous.
Take for instance the HTPA. After exogenous androgens, particularly high doses and long duration...you can see some degree of HTPA dowregulation for 3-9 months. I had to look this up in an endocrinology book & worked with an endocrine specialist for a patient with major problems after a prolonged cycle. Of course, we told him to stay away from all anabolics!