Hillary Clinton recently revealed that she takes Armour Thyroid for hypothyroidism. Why wouldn't she take something more mainstream like Synthroid?
Armour (not "Armor") Thyroid is a "natural" version of thyroid hormone replacement. It's derived from the thyroid glands of pigs, and it has a distinctly "piggy" odor. Doctors recommend it because it contains not just the T4 found in synthetic thyroid hormone but also the the T3 that the body uses as activated thyroid hormone.
Animal-derived thyroid hormone actually provides more T3 than the human body makes on its own. The human body typically has about 14 times as much of the "storage form" of the hormone, T4, as the "active" form of the hormone T3. But in the pigs whose thyroids are used to make Armour thyroid, the ratio is closer to 4 to 1.
Doctors usually prescribe the synthetic product because it leads to more predictable levels of T3 in the bloodstream. Some people (and one would suppose Hillary Clinton is among them) simply feel better when they take Armour Thyroid. Taking the natural product may lead to more ups and downs in energy levels, but when there are also deficiencies in the copper and selenium and zinc the body needs to make the enzymes that convert T4 to T3, it can be better to take a product that contains the T3. If there are problems, they may arise from dosing. It's usually better to take Synthroid once a day but Armour Thyroid twice, because T3 breaks down in the bloodstream rapidly.