I will have to agree with you on your comment regarding Thyro-Gold... however, most of the other OTC products have had the hormones removed and are simply ground up tissue.
I haven't researched the benefits of bovine thyroid hormones vs porcine; it's my understanding that porcine is most like humans, though pigs produce much more T3 than humans do. That's a new avenue of research to be done.
I read this somewhere, and it explains why the FDA don't ban Thyro-Gold:
"The 1994 supplement law forcing the FDA to allow vitamins without restriction allows natural products. However if a medical claim is made for a natural product it falls out of the protection against the FDA. The Thyroid Gold product makes no medical claim and is off scot-free."
It is illegal for any thyroid supplement sold over the counter in the United States to have any measurable thyroid hormones, since thyroid hormones are available by prescription only. Whether the hormones are actually removed or not is another matter... companies selling these products could be subject to issues with the FDA...
Meant to say thyrogold is raw thyroid bovine
You are wrong. Thyroid is whole raw thyroid from New Zealand repackaged in the U.S..
Just for your information, though... you are correct that Thyroid S comes from Thailand. ThyroGold comes from the U.S from the late Dr John Lowe. NutriMed also comes from the U.S.
OTC thyroid supplements in the U.S are not supposed to have any measurable thyroid hormone in them... they are ground up glandular material, with the hormones removed.