Forutsetter at OTC er det samme som Armour:
Over-the-counter (OTC) desiccated thyroid is available through many websites on the Internet.
We know of one downside to using OTC desiccated thyroid products: Patients occasionally find themselves with "weak" (subpotent) tablets or capsules. These tablets or capsules apparently don’t contain the amount of thyroid hormone the products typically do. A week or two after the patient starts using a new bottle that contains weak tablets or capsules, her hypothyroid symptoms reappear, and her TSH level rises.

Occasional weaker-than-usual tablets or capsules, however, aren’t unique to OTC desiccated thyroid. As Mary Shomon has documented, for various reasons, the FDA often recalls prescription thyroid hormone products. Fairly often, the FDA recalls a prescription product because it contains less thyroid hormone than its label states.
http://www.drlowe.com/QandA/askdrlowe/desicatd.htm

Men det kan også skje med syntetiske hormoner? Også i Norge?