Thyroid Versions: Costs and Rough Equivalence

Type Cost per 100 pills
Combined T3/T4
Thyrolar – 1/2 $58
Armour Thyroid 1/2 grain $19
generic Armour thyroid 1/2 grain $12
T3 alone
Cytomel 25 mcg
Cytomel 5 mcg
(to my knowledge, there is no generic T3 available, at least in the U.S.)
T4 alone
Levothyroxine, generic, 100 mcg
Synthroid, 100 mcg

Microgram content per pill

Thyrolar T4 / T3 content
Thyrolar-1 50 mcg / 12.5 mcg
Thyrolar- 1/2 25 mcg / 7.25 mcg
Armour Thyroid T4/T3 contentRees-Jones
60 mg, 1 “grain” 60 mcg/ 10 mcg
30 mg, 1/2 “grain” 30 mcg/ 5 mcg

By T4/T3 content, Thyrolar-1 and a single grain of Armour Thyroid are roughly equivalent, but not identical. When I’ve switched patients from Thyrolar to generic Armour (e.g for cost reasons in some cases) these different pill types seem to produce a TSH value in about the same range as before the switch.

What about switching from T4 alone to a combination? All you need to do is add some T3, right? No, that will raise the total dose. Rather, for a person whose TSH is around 1.0 already, on 125 mcg T4 alone for example, the very rough equivalent seems to be around 1 or 1.5 pills of 1-grain generic armour thyroid, and that must be carefully determined by repeat TSH testing, to get the TSH back to around 1.0 on the combination.