If you increase your thyroid medication can you go from hypothyroidism to hyperthyroidism?

Yes: That is why it is important to be monitored by your doctor regularly.

Yes: That's why ugly should get blood tests ~ 6-8 weeks after a change in your levothyroxine/synthroid dose, to make sure you're not getting too much medication. After you're steady on a dose, less frequent blood test is needed, unless u develop symptoms. Some thyroid conditions have periods of highs and lows too, in the natural disease course (which require med dose changes)...See ur endo to ask.

Technically, no: You can be overtreated and your thyroid hormone levels can be too high, but technically speaking, your thyroid is not over active.