What should my tsh level be ideally?

0.4 - 4.0: It can range as above but i would also recommend checking T3 (liothyronine) or t4. T4 is converted to T3 (liothyronine) which is the active thyroid hormone.

Symptoms?: Some newer literature suggests TSH levels should be below 2.5, depending also on the presence or not of symptoms.

A range...0.5---5: The range varies slightly from lab to lab..Quest vs labcorp vs local hospitals vs smaller private labs etc...But your ideal value depends on u. It may help a bit keeping in the low side if you are heavy and want to lose some wt and vice versa. Otherwise, if you are perfectly healthy, feel well, sleep well...No symptoms and say your TSH is 3.366, then this is ideal! consult your doc.. Good luck.