My gp insists I have underactive thyroid but the diagnosis in 1985 was Riedel's thyroiditis. I have yet to find a gp that understands this.
I was on 125mcg for decades, test results fine, lost all the weight. Dosage changed to 100mcg Jan 2024. I was also given iron supplements & B12 in Jan 2024. Since then I've had 3 different makes of levothyroxine.
My gp phoned me today to reduce my levothyroxine to 75mcg following test results.
TSH level 0.04 mu/L (normal range 0.27 - 4.20) 17 Mar 2025 Abnormal
Serum free T4 level 18.8 mol/L (normal range 12.0 - 22.0) 17 Mar 2025 Normal
I told her about all the vitamin supplements I had been taking, the very low calorie diet and I'd had HMPV, pneumonia then covid in the last 6 weeks. She brushed off the biotin and talked about drug safety and importance of adherence to correct dosages, heart attacks, stroke. Basically, she didn't listen and does everything by the book. I'm concerned there may be another reason for the low TSH. I now have to wait for my next blood test to see if it's improved.
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tamaraznotherday
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Was FT3 not tested? It's actually helpful to see levels of FT3 and FT4 (possible conversion T4 to T3 problem). TSH often gets "abnormally low" or suppressed when on thyroid hormones, the physical symptoms are then more important to note and treat. Besides, in most countries normal upper limit for TSH is 2.5. Biotin should be discontinued some time prior to blood test as it affects parameters.
Riedel's thyroiditis, quite rare, is a chronic form of thyroiditis - was this diagnosed based on a puncture/thyroid tissue probe? Perhaps you ought to consult a endocrinologist rather than GP?
I had a biopsy which confirmed it. T3 Is never tested. The endocrinologist turned me over to my gp many years ago. I'm 70 now. I no longer take biotin, stopped after reading about it on here. I did consider a private test. I might see how my next blood test turns out & will ask for T3 to be included. Thanks for your reply.
When thyroid replacement is prescribed, it should be noted that thyroid replacement also suppresses both TSH and TSH releasing hormone TRH unquote
Actually Free T3 and Free T4 should be measured as in enables you to calculate the functioning of the thyroid. Do you take selenium? Your current GP does not sound very knowledgeable in thyroid matters to me. I also used to get bullox from docs when my TSH was as low as yours while my physical symptoms were clearly evidencing "thyroid in underfunctioning mode" and I felt depleted - lightyears away from a heart attack...
hope you find something in these posts / and their links , which is useful for next conversation with GP assuming TSH is still low, sorry if they are a bit complex , but what you need to deal with GP is in there : healthunlocked.com/thyroidu... useful-evidence-that-tsh-between-0.04-0.4-has-no-increased-risk-to-patients-on-levothyroxine-updated-new-study-does-show-small-risk
If you normally take levothyroxine at bedtime/in night ...adjust timings as follows prior to blood test
If testing Monday morning, delay Saturday evening dose levothyroxine until Sunday morning. Delay Sunday evening dose levothyroxine until after blood test on Monday morning. Take Monday evening dose levothyroxine as per normal
Monitor My Health (NHS private test service) offer thyroid and vitamin testing, plus cholesterol and HBA1C for £65
IMPORTANT......If you are taking vitamin B complex, or any supplements containing biotin, remember to stop these 3-5 days before ALL BLOOD TESTS , as biotin can falsely affect test results
In days before blood test, when you stop vitamin B complex, you might want to consider taking a separate folate supplement (eg Jarrow methyl folate 400mcg) and continue separate B12 if last test result serum B12 was below 500 or active B12 (private test) under 70
I'll book a private test next week and follow all the steps to get an accurate reading. I doubt I need antibody test as I no longer have a thyroid, it's shrivelled up and died? Today, like any other day I literally dragged myself to go shopping, now exhausted and haven't even started on the lower dose.
It sounds like you've had three major illnesses recently. As a result, you might have Non thyroid illness syndrome NTIS. This is where your TSH drops but your fT3 level drops too. It sounds like your your doctor is dosing by TSH, and is unaware that these conditions exist.
You need to test TSH, fT4, fT3 (and if possible rT3 so you can prove the T4 you are taking is being converted to rT3 instead of T3).
By the way, it sounds like you having Riedel's thyroiditis in 1985 caused your underactive thyroid. It's actually irrelevant what the cause is of having an interactive thyroid, the treatment is the same. So your doctor is right to not pay attention to your Riedel's thyroiditis diagnosis.
Just picked up my new prescription Vencamil & Wockhardt. Looking through the repeat I got last month (which I now can't use) , there are 2 different makes, Teva & Accord.
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Could this be Hashimoto's
test results 
How can I tell if I need another levothyroxine dosage increase?
After Some Super Advice on This Forum
Thyroiditis?
