I'm no medical expert, navigator, but the 'vet' and his 'textbook' mindset - Was of no use, whatsoever.
I had to demand a prescription (He was certain would have no effect).
The 'vet' is now more 'learned' and the thyroid issue is resolved.
Brief: 'Brown thing', my dog - 11yrs-old - Boxer/staff runt - Born with a rare genetic 'fox' mange - testes removed at 8 months (Non-development) = low testosterone production, overworked immune system - Organ debilitation = thyroid incapacity.
Thus - The thyroid, thyro, calcitonin, t3, t4 - Was NOT the primary cause of his downfall - Once I stalled the infection - Thyroid productivity normalised.
addition: He doesn't eat processed foods anymore. They are nutritionless poisons that fund the pharmas.... another story.
I would suggest a daily dose of kelp (available at any heath-outlet) in supplement form - To everyone.
Also, if you don't source your own 'food' - You don't control your bio-functions.
Take a look at the issue from a 'natural' perspective - Don't rely on 'standardised' medical processes, alone.