In range doesnt mean tiddly. Most Thyroid experts would suspect thyroid issues if TSH is above 2 when not on thyroid meds. TSH is only a rough guide, stronger players are Free T3 and Free T4, they generally should be in upper quartile. However these are only blood, not cell levels, cell levels are what is needed and thyroid experts especially the older ones tend to say look at temperatures, pulse rate, blood pressure and other physical symptoms. Then when we think we have it sussed its important to mention thyroid will only work properly if adrenals are okay. So its a bit complicated for sure but having TSH under 2 and Free T 3 in upper quatile is a starting basic point. The website and book Stop The Thyroid Madness explains all this quite well. Another good book if still in print on thyroid is by Doc Barry Peatfield