I was diagnosed with Graves Disease in July 2020 after reporting feeling uneasy, shaky, urinating frequently and having some hair loss.
My T4 returned to normal levels quite rapidly without medication.
I have had since had flair ups (had my T4/TSH measured) and both resolved on their own.
This year I had another flare up and my symptoms were very uncomfortable. My T4 was the highest it had been (38 pmol/L ) and my TSH less than 0.01 so I agreed to go on a small dose of Carbimazole (10mg per day)
Within 5 weeks, my next bloods showed my T4 dropped well into normal (14 pmol/L) though my TSH is still less than 0.01.
My menstural cycle during this time has been strange - my first period came after 21 days and my second after 16 days (!) I also feel a bit strange around my period and have symptoms I don't normally have.
Given how quickly my T4 dropped I worry I may be going hypo/don't know what to do - my next endo appointment isn't until May!
What I am curious about is
- If my T4 dropped so quicky should I stop or reduce my carbimazole?
- Has anyone else had their period affected by carbimazole/thyroid fluctuations?
Written by
kscourt
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There are 2 thyroid related auto immune diseases that start off the same way and can cause high over range T3 and T4 readings - and you can only tell these apart by which antibodies were found positive and over range at your initial diagnosis blood test.
With Graves the T3 and T4 keep rising higher and higher and considered life threatening if not medicated and why an Anti Thyroid drug is prescribed to semi - block your new daily thyroid hormone production while we wait for your immune system response to calm down and your high thyroid hormone levels slowly fall back down into range,with the AT drug titrated accordingly so your T3 and T4 do not fall too far through the ranges and you experience the equally, if not more disabling symptoms of hypothyroidism.
With Hashimoto's the thyroid levels do not rise so high and the T3 and T4 fall back down into range by themselves without medication but progressive AI ' flares ' will damage the thyroid and you may well find you become hypothyroid as your thyroid gland becomes fully disabled.
Some people do have Graves and Hashimoto's running alongside each other ?
Are your eyes affected - sore, dry, gritty, streaming or light sensitive ?
So I think the first question has to be - can you please share your blood test results and ranges at diagnosis -
ideally there should be a TSH, Free T3 and Free T4 report - and which antibodies were found positive and over range in your bloods - this might look like TPO - Tg AB - TRab- TSI - readings and ranges/numbers and or words like TSH thyroid receptor antibodies and coul be a separate result/range a few days after the in depth initial blood test.
I have had issues with my eyes (gritty eyes and lid retraction) and was diagnosed with Graves Disease originally in 2020. From 2021 to 2022 I was in remission and symptoms started again in 2023.
Here are all the blood results I have to hand:
Antibodies February 2024:
Thyroid Receptor AB 31 iu/l
Serum Thyroid Peroxidase AB >600iu/mL
Serum TSH:
July 2020, September 2020, April 2023, June 2023, Jan 2024 and Feb 2024 all <0.01 mu/L
Serum T4:
July 2020 29 pmol/L
September 2020 20 pmol/L
April 2023 24pmol/L
June 2023: 21.9 pmolL
January 2024: 38 pmol/L (started 10mg carbimazole Jan 6th)
February 2024 (6 weeks on carbimazole): 14.7pmol/L
Since taking carbimazole my t4 levels have dropped quite rapidly and I had a 21-day cycle and now a 16-day cycle.
That being said, I was having uncomfortable palpitations and feeling dizzy and tired and generally unwell at the start of Jan and that has subsided. I am tired but feel overall better apart from my menstrual issue now.
a Graves Disease Thyroid Receptor at 8 - and a TPO at 600 - which is for Hashimoto's - which I think are both over range and positive by most ranges I've seen - do you have any ranges there for these antibodies ?
Both Graves and Hashimoto's are Auto Immune disease for which there is no cure and the treatment for Graves with an Anti Thyroid drug will take precedence.
As for your eyes are you seeing a specialist opthalmologist ?
The Thyroid Eye Disease Charity - TED- tedct.org.uk can signpost you to specialist clinics throughout the country, generally attached to large teaching hospitals, where an endocrinologist and an eye specialist work in conjunction on medication so to cause the least trouble to future eye issues ; please be sure all drops are Preservative Free - even those prescribed by the NHS.
Ok then - so with Graves you can have both blocking and stimulating antibodies taking turn to attack your body and you can experience extremes of symptoms and all the AT drug, Carbimazole, does is semi - block your new daily thyroid hormone production and slowly your T3 and T4 fall back down into range and hopefully with your symptoms relieved.
With regular blood tests your AT drug dose is adjusted down, as your immune system calms down - though quite why your immune system ' took off ' and ' why me - why now ' - a whole other conversation.
When metabolism runs too fast as in hyperthyroid or too slow as in hypothyroid the body struggles to extract key nutrients through food no matter how well and clean you eat -
and non optimal levels of core strength vitamins and minerals - ferritin, folate, B12 and vitamin D can compromise your health further - so suggest you ask your doctor to run these blood tests and we can advise where these need to be to optimise your health during this phase of ill health.
I am ' guessing ' that your periods could well have been affected with your body clock running faster than normal - it seems logical - but - your doctor should know for sure.
Without the ranges and a T3 reading it's impossible know if both your T3 and T4 are now in range - but your T4 now ' looks low ' - your dose of the AT drug may need to be reduced down so you don't fall too far through the ranges and experience the symptoms of too slow a metabolism and hypothyroidism.
Currently the NHS allocate around a 15-18 month window with an AT drug and the hope is your immune system calms down well and your T3 and T4 fall back down into range without the need for any medication and this ' just a blip ' .
You might like copies of the most recent research into Graves treatment :
The ranges for my tests are added below (**updated as Thyroid Receptor AB was previously incorrect**
I am seeing an ophthalmologist for my eyes every 6 months and am on drops. My lid retraction subsided after around 1 year.
My endo does not feel that I have Hashimoto's - I had heard this before about the antibodies and asked her and her opinion is TPO can be present in Graves too, and I have never shown any symptoms for Hashimoto's.
What I am most curious about is my menstrual cycle changes - I am wondering if anyone on carbimazole has had a very short period - after just two months I had a cycle of 21 days and now just 16 days. I am wondering if this is related to carbimazole and if anyone has had a similar experinece? It is making me want to cut my dose further as it is really unpleasant and concerning having such short periods.
Thank you again
Thyroid Receptor AB (range 0-3.3 iu/l)
September 2020: 8 iu/l
January 2022: 3.5 iu/l
February 2024: 31 iu/l
Serum Thyroid Peroxidase AB (range 0-34 iu/mL)
February 2024: >600iu/mL
Serum TSH (range 0.27-4.2 mu/L)
July 2020, September 2020, January 2022, April 2023, June 2023, Jan 2024 and Feb 2024 all <0.01 mu/L
Serum T4 (range 11.1-22 pmol/L)
July 2020: 29 pmol/L
September 2020: 20 pmol/L
April 2023: 24pmol/L
June 2023: 21.9 pmolL
January 2024: 38 pmol/L (started 10mg carbimazole Jan 6th)
February 2024: 14.7pmol/L (6 weeks on carbimazole)
Ok - so AB - is the antibodies and for both Graves and Hashimoto's and positive and as detailed these can run together and Graves Disease treatment takes precedence -
Your T4 is well in it's range at just round 33% but without a T3 reading and range -we can't assume anything -
the TSH may be very slow to recover and for some people - like myself - never recovers normal function and why it's essential to dose and monitor on Free T3 and Free T4 readings and ranges.
I'm sorry I haven't a definitive answer for you regarding shorter cycles and if no one else comes along to answer you I'm sure your doctor can put your mind at rest on this one point,
My menstural cycle during this time has been strange - my first period came after 21 days and my second after 16 days (!) I also feel a bit strange around my period and have symptoms I don't normally have.
I had similar irregular periods when first on Carbimazole. Now my thyroid levels are stable on 5mg (and have been for 12 months) my cycle has returned pretty much to normal.
Given how quickly my T4 dropped I worry I may be going hypo/don't know what to do - my next endo appointment isn't until May!
This happened to me when first on Carbimazole. My FT3&4 returned to normal much more quickly than my TSH. My Endo writes to my GP after each appointment and his letters have always included advice about blood tests and adjusting the dose if I'm over/under range. Maybe have a chat with your GP and she if they've had anything similar?
Thank you so much it is helpful to hear - having such a short cycle was a bit concerning and I can't find much about it.
My endo did send a letter to the GP but she hadn't see these second results when she sent so hopefully she has some further advice after seeing this Thanks again
I have short cycle when my T4 levels are lower and I feel more hypo. I’ve just had a 19 day cycle and feel quite hypo, heart rate is lower, aches, swollen feeling etc. It’s happened a few times over the last few years. I have the Hashi TPO antibodies but haven’t been tested for Graves, but have had more than one episode lasting a few months over my teen/adult lifetime that could have been a Hashi flare/Graves like episode. In June/July last year my FT4 went to 28. More recently it was only 60% through range and I suspect dropping, I’m going to test again to confirm.
Cycle has in the past returned to normal with increasing T4 dose slightly and I’m hopeful I can do that again slowly.
Have you checked your ferritin? Mine drops like a stone with short cycle periods which makes me more hypo. When I supplement heavily with something strong like 3 Areows heme, and ferritin is top of range I can lower my thyroid replacement dose. Still working on the perfect balance for me 🌱
Thank you for this it is helpful to hear I am sorry you also get these symptoms. The short cycles are really unpleasant!
I have always had low ferritin - I have prescription iron but I don't tolerate it well (I get quite bad gastro symptoms from it)
My last ferritin in Jan was 22 ug/L (range 30-150 ug/L) I just started taking Nutri Advance FerroDyn which I have found I can tolerate well so I am hoping this helps!
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Thanks again 
Low T4 result being on T3 only
Hyperthyroid help
Results - is my TSH 'too' low?
Graves' disease ???
