I am a male, 39y/o and was diagnosed with hyperthyroidism in March 2025, with initial results showing TSH < 0.01 and FT4 at 34.6. I started on Carbimazole 20mg daily on 4 March 2025, along with Propranolol. Within a few weeks, my symptoms—tachycardia (112 bpm), shortness of breath, and anxiety—resolved, and I began to feel normal again.
I had follow-up blood tests on 6 April 2025, which showed TSH still < 0.01 but FT4 had come down to 12.54. Despite this, my Carbimazole dose was maintained at 20mg daily.
Over the past few days, however, I’ve started experiencing dizziness, a sensation of internal movement in my head, head pressure, and ringing in my ears. I’m unsure what’s causing this, as it seemed like my condition was stabilizing based on my latest test results.
Could this indicate that my dose needs to be reduced? Anyone else experience this as well?
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AS_007
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Test TSI or Trab antibodies to definitely confirm Graves’ disease
Also TPO and TG antibodies for Hashimoto’s, autoimmune hypo thyroid disease. Hashimoto’s frequently starts with transient hyperthyroid results and symptoms
Also important to test vitamin D, folate, B12 and ferritin
What vitamin supplements are you taking if any
How much propranolol are you taking
When this is reduced it must be done so very slowly
FT4 very much reduced. I think what might have happened is dr looked at TSH and decided you need to continue lowering thyroid levels more. Dose should really be adjusted down.
TSH can be unreliable, can remain suppressed after period of hyper. Going by FT4 discuss with doctor & the dose is often reduced by half to keep thyroid levels within range.
Retest in 6 weeks, might need adjusting further.
Ideally FT3 is also tested.
Hyper can also be transient, continuous hyper needs to be confirmed by positive TSI or TRab antibody result.
Some get symptoms with lowering propranolol. I got migraines for example. Others aren’t affected, 10mg was low dose so sounds like you were ok to stop.
Generally speaking if there are no physical signs of a swelling in the neck ara and you hve no problems swallowing or breathing -
there are 2 Auto Immune diseases that can attack the thyroid and cause ' hyper ' type symptoms and an excess of thyroid hormones with high over range T3 and T4 readings and cause such symptoms as you describe.
Both Graves and Hashimoto's are AI diseases, and can attack the thyroid and or eyes -
It is essential that your thyroid antibodies are run so as to distinguish exactly which AI disease you are dealing with - as -
only Graves is treated with an Anti Thyroid drug - such as Carbimazole -
as with Hashimoto's the immune system attacks are transient and the thyroid is able reset itself without the need for any drugs in the first instant - but longer term with successive attacks the thyroid becomes disabled and the patient becomes hypothyroid and needing thyroid hormone replacement - T4 Levothyroxine.
Generally if the Graves Disease the treatment plans is around 15-18 months with an AT drug which dampens down the immune system and just buys you time, while we wait, for your immune system to calm back down again and hopefully your thyroid reset itself without the need for any drugs.
Propranalol is a better blocker and can be prescribed if the heart needs protecting , and also slows down the conversion of T4 into T3 as it is too high a T3 causing the horrible symptoms.
Your T4 at around 35 is not too far over most ranges - and with your T4 now at 12 and likely in most ranges - the AT drug needs reducing as otherwise your T4 will fall too far through the range and you will be dealing with the equally disabling symptoms of hypothyroidism -
I have to say that this looks more like Hashimoto's than Graves -
but we must run the antibodies to know for sure -
These look like TPO - TgAB - TRab - TSI - or TSH Thyroid Receptor - reading and range - do you have access to your medical records held at the surgery - as you may find these there ?
Should you have Graves Disease - I detail below the most recent research we have :-
Thanks. No I dont have access to the Medical Records just the bloodwork results done for TSH and FT4 levels.
Based on the responses I do believe that I need the antibodies done to be 100% sure. Just a sidenote, I have been to 2 GP's and both recommended 20mg Carbimazole after the initial TSH and FT4 levels.
Most Laboratories run what is called a Cascade Method when analysing blood tests :
1st they start with the TSH - if ' in range ' - it maybe all that is run :
If out of range a T4 is run - if T4 out of range - antibodies will be automatically run -followed by a T3 reading -
The medical evidence and proof of diagnosis is whichever antibodies are found positive in your blood test - and should be detailed and confirmed prior to a prescription being written.
When the thyroid malfunctions several sets of antibodies can be found positive - but Graves take precedence as said to be life threatening - if not medicated.
Suggest you arrange to have online access to your medical records held at your primary care surgery as then you can track your results as they are released -
just ask the receptionist at your surgery for the form and think you'll need to offer some form of ID :
Here are the respective test results. As mentioned before, thats from 20mg Carbimazole p/d since 07 March 2025 (and 10mg Propranolol p/d for 1 week ONLY then stopped).
All symptoms subsided after 2 weeks of Carbimazole but continued the 20mg dose.
Current symptoms : Extreme Head Pressure, Dizziness, Confusion and lightheadedness (all started 3 days ago.
Unfortunately I can't see any antibodies on this print out - so all we know is that originally you were classed as ' hyperthyroid ' - but we need to know the reason ' why ' and which antibodies were found positive and over range in this first blood sample -
Is there anything detailing - TPO - TgAB - TSI - TRab - TSH Thyroid Receptors - and ranges ?
Your TSH was 0,01 and your T4 over range - and 20 mcg Carbimazole was prescribed:
Your TSH is still 0,01 and now your T4 is just 35% through its range and the Carbimazole
and needs reducing as your T4 now too low and causing you symptoms of hypothyroidism.
When taking an Anti Thyroid drug we need to try and maintain both the T3 and T4 at around 50% through the ranges.
Suggest you speak with your doctor as the NHS should have already run the necessary antibody blood tests and ask if your dose of Carbimazole should now be reduced ?
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HYPER Carbimazole Dosage
Help please FT4 almost below range - feeling tired - hyperthyroid no more?
Stopping carbimazole 
weight gain and hyperthyroid
