Most doses of thyroid hormones (levothyroxine or liothyronine) are in micrograms - abbreviated mcg.
Members here will mostly understand if you make a mistake. But it really does help to get this right when talking with (or writing to) doctors. It is an immediate "win" in terms of showing your understanding.
There is a section on various measurements in helvella's Vade Mecum document which is available here:
helvella - Vade Mecum for Thyroid
The term vade mecum means:
1. A referential book such as a handbook or manual.
2. A useful object, constantly carried on one’s person.