Optimal thyroid function for longevity involves low TSH, mid-range free T3 and free T4, low reverse T3, and absence of antibodies.

“And I I tend to lean more toward this sort of rate perspective that you want your body temperature to be high and you want your thyroid to be basically happy and partying all the time. You want the thermostat turned up in your house and you want to see your TSH low, certainly below two. You want to see free T3 and freeT4 free T4 robustly in the middle of the reference range, not at the low end of the reference range. and you want to see reverse T3 low and you want to see obviously your antibodies non-existent.”