Selenuim will not help with symptoms. Seleniun with a few other vitamins/minerals will help thyroid in general.
Normally a TSH of 3 doens't come with symptoms,
Your symptoms might be from something else, like other health conditions, which share a lot of thyroid symptoms.
I do take Selenium and the other vitamins/minerals. Does it help? who knows, I truly can't tell. I just take them for general good health.
Keep in mind that there is no miracles out there. Just treatment and medication.
Good Luck - Good Health
Selenium in that amount reduced antithyroid antitbodies by 10-15% in some pregnant women studied.
Might help if you have elevated antibodies, or it might not.