Thyroid UK

How much levothyroxine?

Hi, I'm new to this so please excuse me if this has already been asked. My GP has prescribed levothyroxine for under active thyroid and I'm on 75mg dose, blood test result said all was good but I still feel constantly exhausted and generally blurgh. Any tips on correct dosage for an 85kg guy, or general tips on what I can do to feel any better? Thanks in advance

4 Replies

Whecox Generally bleugh - yes, a good description which a lot of us can relate to :)

Correct dosage doesn't really depend on weight, it's whatever is needed by the individual to feel well.

So let's get the full picture.

When were you diagnosed?

Is 75mcg your starting dose or have you had an increase?

Have you been re-tested since being on 75mcg?

(Actually, 75mcg is a tiddly dose anyway, let alone for a 13 stone man, I don't weigh that much and I'm on 150mcg plus some T3.)

Do you have your thyroid test results? If not then you are legally entitled to them (Data Protection Act) so request them from your surgery, they may make a small charge for printing. Make sure the reference ranges are included and make a new thread with those results so members can comment.

Also, have you had thyroid antibodies tested, and Vitamins and minerals? If not, ask for them. Ideally we need




Thyroperoxidase antibodies

Thyroglobulin antibodies

Vit D




That will give a good picture and show any deficiencies that may need addressing.

If you can't get all those tests through your GP then we can tell you where you can get them done privately with an easy fingerprick test at home if you're in the UK.


Hi there, I Have been diagnosed in 2011 with hypothyroidism and never being tested for all those. Ihave been reduced to 50mg of levothyroxine and I am getting worse with my symptoms and weight. Could you please let me know where can I have this test done and maybe suggest a private doctor? I live in London.

Thanks a lot



ButterflyG I have answered you on your thread you have started :)


Based on the rough guide of 1.6 mcg per kg, you should be on 125 - 150 mcg of Levothyroxine.

GPs may be happy for their treated patients' TSH to just dip back into range (under 5), yet healthy (euthyroid) men have a TSH at the lower end of the range. When treated, it's recommended to have TSH at 1 or below, but that's no guarantee for not feeling blurgh.


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