For patients on desiccated bovine thyroid hormone therapy, how do you approach transitioning to synthetic thyroid hormone derivatives?  

The US Pharmacopoeia specifies that a1 grain (65 mg) dose of desiccated thyroid have approximately 38 mcg of T4 and 9 mcg of T3 (Blumberg et al., PMID 3598896). If T3 is approximately 3-4 times as metabolically potent as T4, then 65 mg of desiccated thyroid has about 38 + (4 x 9) = approximately 75 ...

There are no FDA approved bovine desiccated thyroid. The only form that is available at a pharmacy is porcine desiccated thyroid. The bovine desiccated thyroid supplements purchased over the internet/health food stores do not have any significant L-thyroxine (T4) or Levothyronine (T3). Just stop the...