Abstract: Described is a microneedle device, preferably a controlled release device, for delivery of liothyronine (LT3 or salt thereof) to a patient with hypothyroidism and/or who is not pregnant. The microneedle device contains LT3 or salt thereof in an effective amount to maintain normal, stable levels, in the serum, of free and/or total T3. The microneedle device includes at least two components: multi-dimensional array of microneedle(s) and a substrate to which the base of the microneedle(s) are secured or integrated. The microneedles contain LT3 or salt thereof as well as a biodegradable and/or biodissolvable polymer, such as polyvinyl pyrrolidone for controlled release of LT3 or salt thereof. Also described are methods of making and using the microneedle device.