My 9 year old golden retriever developed 2 bald spots on his back in places where he couldn't scratch (he did not seem itchy), the skin had turned black in those spots and he also had thining fur in a T shape on his back towards the tail. I looked it up and they seemed to be symptoms of hypothyroidism. Before taking him to the vet I tried Ted's suggestions, added kelp powder, lugol's solution, vitamin C, vitamin A, humic acid, plus thyroid granule, L-tyrosine, astragarus, selenium and coconut oil to his food. In 2 months his fur grew back, the T shaped thinning spot disappeared and the black color from the bald spots lightened everyday. I am hypothyroid as well and am on synthroid for life and I did not want that for my dog.
I got my humic acid from bioag.com pet section. Thank you Ted, you are awesome.