The problem is, that when taking levothyroxine, the TSH gets low or suppressed in patients, even if they are on a lower dose. The reason for that is that the TSH/T4 feedback from the pituitary is not working in the same way as it does in a person without thyroid disease - but many GPs will not acknowledge this.
The only thing you could ask him, why the NICE guidelines state that a normal replacement dose is 1.6mcg per kg of weight. So if you weigh 100kg, you should be on around 160mcg levothyroxine. That surely would still apply even if your TSH is suppressed?
In conclusion, pituitary TSH cannot be readily interpreted as a sensitive mirror image of thyroid function because the negative TSH-FT4 correlation is frequently broken, even inverted, by common conditions. The interrelationships between TSH and thyroid hormones and the interlocking elements of the control system are individual, dynamic, and adaptive.
Importantly, tetraiodothyronine (T4) to T3 conversion efficiency may be impaired in patients receiving LT4, resulting in a loss of thyroid-stimulating hormone (TSH)-mediated feedforward control of T3, alteration of the interlocking equilibria between serum concentrations of TSH, free thyroxine (FT4), and free triiodothyonine (FT3), and a decrease in FT3 to FT4 ratios. This downgrades the value of the TSH reference system derived in thyroid health for guiding the replacement dose in the treatment situation.
Daily.... perhaps you could push your GP to seek the advice of the Endo Dept as your fT4 is low and you continue to be symptomatic which they are supposed to take into account?
This is interesting because I have noticed that many patients with Hashimoto’s disease and hypothyroidism, start to feel worse when their ferritin drops below 80 and usually there is hair loss when it drops below 50.
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New to site - hello!
Tgab elevation low t4 
Latest results - increase further?
Advice please from you lovely people please.
Should I request an increase in thyroxine?
