T3 only GP wants me to add T4: iv been on T... - Thyroid UK

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T3 only GP wants me to add T4

Kellogs profile image

iv been on T3 25mg only now for 4 mths I confessed to my GP i self medicate after many years of being unwell and T4 not working . I had a blood test but took my T3 by mistake so result was T3 8.9 ref 3.5-7.7 TSH 36. Why do they do TSH when on T3 only ? she wants me to add 50 mg of T4 which worries me as this will push up T3 she said it wouldnt . how do i prepare for a blood test that will be acceptable in ref range but not mess up my self meds as i feel better than i have in many years. Best mention iv had TT due to graves.

20 Replies

Sounds as though she just wants to cover her back and protect her job. Bit rich really when she prescribed thyroxine which left you feeling poorly.

TSH is meaningless when taking T3, especially when you've not long taken a dose. If you're feeling better then continue with the T3, accept the prescription and just file it away. You don't want to throw away the progress you've been making just to appease a doctor who probably knows nothing about T3.

Kellogs profile image
Kellogs in reply to

thankyou cinnamon girl. i know she dosent rate T3 from what she has said but i did tell her i would self medicate as iv done all that was asked of me over many years and now that iv confessed to her after the event she did say that it is possible to get on prescription but didnt want me doing it alone, so i will add t4 to my meds as although i feel better theres still need for improve in areas, and see how it goes but i wont come off T3 .

Kellogs, TSH is relevant when taking T3, and yours shows you are undermedicated on 25mcg T3 because TSH 36 is very high. That's why your GP wants to add 50mcg Levothyroxine (T4).

Taking T3 within 6 hours of a blood test skews the result and FT3 levels may peak at 2 or 3 times normal. I suspect your normal circulating FT3 is very low because your TSH is so high.

Why not try the T4+T3 combination? I don't tolerate T4 only but am well on T4+T3.

If you are determined not to resume T4 you need to increase your T3 dose. 3/4 tablet (18.75mcg) equivalent to 56.25mcg T4 is the closest you'll get to the 50mcg your GP prescribed.


I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

Kellogs profile image
Kellogs in reply to Clutter

thankyou so much clutter wasnt quite sure which way to go as i didnt want to undo all the work id done so far i will add T4 of 50mg with my T3 of 25mg and she has asked for bloods again in 6 weeks . she did say she was concerned about me and it is also putting her in a position with the practice which i do understand thats the way it is unfortunately. but she is the only dr that is willing do T3 for both myself and my younger daughter so dont want to loose that .

Kellogs profile image
Kellogs in reply to Clutter

Clutter just checked bloods T3 9.3 (3.9-6.7) which is a little higher also TSH 36.9 (0.2-5.5) just a little higher. sorry

Clutter profile image
Clutter in reply to Kellogs

Kellogs, taking T3 before your blood test skews T3 results but TSH indicates you are undermedicated on 25mcg T3.


I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

shaws profile image

I am on T3 only and leave 24 hours between my last dose and the blood test. The lab knows I'm on T3 only so they accommodate that and so far they and doctor are happy with my results i.e. low TSH, T4 etc.

Once I did take T3 before blood test and the results were completely skewed and doctor was so concerned that before he spoke a word I said 'don't worry about results' I took T3 before the test. Please let me have another and he did and it's been smooth going every since.

I have alarms and after my T3 dose the day before blood test I put T3 somewhere else so I'm not on automatic pilot. Also before going to bed another alarm and on wakening as a reminder, so it doesn't happen again.

Following on from Clutter your TSH is too high so your dose of T3 is too low.

in reply to shaws

Shaws, I posted yesterday about my TSH being below 1 on t3. I now realise from your reply to cinnamon that I'd taken my t3 on the morning before my blood test! I knew no different then. I've never been told by medics about this. Thanks. X

in reply to

Sorry it's early morning, I meant reply to KELLOGS,

Kellogs profile image
Kellogs in reply to

Thankyou mabsie when the lab test came back it did ? did i have meds before test as this would raise levels above range.

shaws profile image
shawsAdministrator in reply to

You were never told by medics as they are unaware of the peak in our blood for a few hours after taking T3. The same routine below should be used for levo as well.

We are older and wiser each day, whereas the medical profession seem to be backwards. Don't rush onto anything else yet and see how you feel. It's how we feel that's the most important thing.

So for any thyroid blood tests in future you make the earliest possible, fast (you can drink water) and allow 24 hours gap between last dose and test and take it afterwards. This allows the TSH to be at it's highest point (mine below 0.45 (lab said normal).

If we are to get well we have to read and learn otherwise other more serious conditions might develop.

Kellogs profile image
Kellogs in reply to shaws

thankyou shaws i did just take meds on auto pilot as you said then only when i was at hospital though did i or didnt i . i wasnt sure why she asked for TSH she did put on notes T3 medicated only so no T4 was even asked for.

Is that TSH a typo? Seems odd that your FT3 would be slightly overrange (and yes, it would be because you took your T3) but you still have a TSH of 36. It wasn't 3.6, or 0.36 was it?

Anyway, as others have said, you don't need T4. A raise in T3 if that TSH is right, but not T4. Just another doctor who doesn't understand how thyroid hormones work, it seems.

Kellogs profile image
Kellogs in reply to Jazzw

thankyou Jazzw yes it was def TSH 36 and whilst on T4 only meds which was allways top of ref range it never moved off 0.05

Why don't you just ignore her? And go on increasing T3 until you feel well. Or you could try adding T4. If your bloods were within 6 hours of taking T3 you'd expect T3 to be high. I'm assuming your TSH result is a typo.

thankyou angel of the north . im hoping and so far i have managed to get her to work with me after no results and then self medicating and as i said she is the only Gp willing to do T3 no question asked and the lab never refuses her as they do others that have requested but sill ignored. she has even said i could get T3 on prescription but iv got to get bloods in range so worth sticking with for the mo. i think theres only so far they can go without the practice refusing to fund its just the way it is sad but true. i do think she knows how to get around some of the pit falls so to speak,

Kellogs profile image
Kellogs in reply to Kellogs

TSH was def 36 by the way i do keep copys of all my blood test , as i said when on was T4 only TSH was allways 0.05 for 10 yrs more or less after TT due to graves . At least i know my piturity is working now.

Clutter please advise T3 9.3 (3.9-6.7) TSH 36.9 (0.2-5.5) just checked bloods and this is the correct results . a little higher on T3 and a little higher on TSH . sorry

Excuse my cynicism but she probably receives some sort of incentive for promoting & peddling T4 Levothyroxine!! My doctor tried to force it on me & when I sort of jokingly asked him how much the drug company was paying him to promote Levothyroxine he looked rather sheepish & embarrassed! :-(


I agree with Clutter that you either need to increase your T3-only dose or add T4. You are undermedicated on 25mcg of T3-only. Some people feel well on the right T3/T4 combination, others can only feel well on T3-only. You need to find what works for you best and they only way to do it is trial and error, I'm afraid. You need to have good iron and D3 levels, especially on T3-only.

I take 50mcg of T3-only as it's the only thyroid medication I can tolerate.

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