TSH below range - should I decrease Thyroxine?

[Syd35]

I have been taking 150mcg Thyroxine (decided to experiment as was taking 100 / 125 alternate days) and since upping and taking iron for low ferritin have been feeling a lot better.

Latest bloods show TSH 0.05 (0.55-4.78) and T4 18 (10-25) doctor wants me to reduce down to 125mcg per day but just worried this will upset the balance again.

For info the bloods in April this year were TSH 0.68 (0.55-4.78) and T4 stayed the same at 18 (10-25).

Any advice gratefully received.

[shaws Administrator]

You don't need to reduce but your doctor should test your Free T4 and Free T3 first before any decision is made.

Both FT4 and FT3 in particular should be towards the upper part of the ranges. These are very important and it is really unfortunate that all of the doctors and endocrinologists seem to only take account of the TSH and maybe a T4 before deciding we're under or over.

The fact is that the lower our TSH is the better we usually feel but they seem to be confused and believe that a very low TSH means we've gone hyperthyroid and will have a heart attack. TSH means thyroid stimulating hormone and it is from the pituitary gland which, when thyroid gland is struggling TSH begins to rise and in other countries if it is above 3+ people are diagnosed but in the UK it is 10 and people can be quite symptomatic by then. Before blood tests were introduced, we were diagnosed on clinical symptoms alone and given a trial of NDT (natural dessicated thyroid hormones). The aim is a TSH of 1 or lower with FT4 and FT3 in the upper part of the ranges.

Ask GP to test FT4 and FT3, probably wont but you can have a private one through one of our labs if you wish to confirm FT4 and FT3.

Do you get your blood draw at the earliest possible time, fasting and allow a gap of 24 hours between your last dose and test and take afterwards.

[SeasideSusie Remembering]

Syd53

Ask your doctor why you should reduce your Levo when your FT4 (the thyroid hormone, TSH is not a thyroid hormone) is only 53% through it's range.

As Shaws says, get your GP to check FT3 also, chances are that's quite low in range with your current FT4.

[Aurealis]

The goal of treatment is to make you feel well. Success!! You do! Perhaps your gp would like to recheck the blood tests, they’re really not that sensitive that you can successfully adjust your dose to them. I agree that you need fT3 and fT4 need measurement, not just tsh.