Originally Posted by mrsD

If you do well on pig gland extracts, that is your choice.
In medicine not all things are totally "known". It is only after something happens that new ideas are considered. The future may hold new discoveries. In the world of insulin supplementation, both Beef and Pork insulin are history. That is just one example.

Here is one article about it:
http://www.endocrineweb.com/conditio...hypothyroidism

Thus, there is no 100% answer to your question at this time.