How do I dose combo t4/t3 equal to 125 mg of levothyroxine

Have stopped my t4 levo six days ago and need help to get correct dose of 125mg with a combo t4/t3 I brought from pharmacy in Greece, I have panhypopituitarism and under endo who has now said the 25/30 mg hydrocortisone, 100mg levothyroxine and hgh daily injection are all at correct levels now (it has took 18 months of testing), I have took levo for 28 years for hashimoto hypo and have always still had symptons and many issues, he is adamant he will not precribe ndt or anything but levo so have no choice but to trial others by self medicating. I have checked vit d, B12 ant they are mid range and I use supplements ie: selenium, garlic oil, calcium, omega 3 but still have cfs, shortness of breath, chronic aching joints all the usual for us thyroid people. I WOULD IDEALLLY like to use ndt but it is harder to source so will start with t4/t3 combo as got it but really donnot know how much or when to take so would appreciate any info on this.

7 Replies

If you remember that 10mcg's of T3 = 50mcg's of T4 you can then work it out from there. Are you T3 tablets 20mcgs or 25mcg's?

Moggie x

Sorry to disagree but 10 mcg L-T3 equates to about 30 mcg L-T4. This is confirmed in a recent paper by Celi " ".

I believe the confusion arises becasue a number of studies compared serum levels or in-vitro experiments and found a 1:4 or 1:4.5 ratio. However, thyroxine and liothyronine have different absorption profiles and different half-lives which explains why the ratio is different when ingested in tablet form. The ratio you put in your mouth isn't the same as the ratio you consequently get in the blood.

There has been so much research based on a 1:4 or 1:5 ratio, which of course is invalidated, so many L-T3 / L-T4 trials that are useless. I would have expected endocrinologists to know the difference between blood levels and the amount you put in your mouth.


If I went by the 1:5 ratio I would be very hypo. I need much more t3 than this would suggest.

I was advised to take 10mcg of T3 and drop levo by 50mcg. I did this until I took no levo at all and T3 only. It worked fine. With T3 and you do take a little too much, it is easy to reduce dose or mis it for one day.

This is for info:-

Thanks for replies but still confused, the combinatiom drug I got is 50mg t4 and 12.5 of t3 in one pill (all I could get when I was on hol in Greece last year) I am at present on 125mg of t4 only levothyroxine which I take before bedtime so how do I adjust this pill to equate my dose and when is best to take it, still in evening?.

1.5 pills ie 75mcg T4 + 18.75mcg T3 = 131.5mcg if T3 to T4 is x3,

150mcg if T3 to T4 is x4 or

168.75mcg if T3 to T4 is x5.

Why not start with 1.5 pills. If you get hyper symptoms alternate 1.5/1 pill every other day for a week and then try daily again. You can increase to 2 pills in a similar method if your symptoms haven't resolved.

T3 suppresses TSH and FT4 so your TFT will reflect this. If your symptoms are noticeably improved it's worth admitting that you are self medicating and hopefully your endo will agree to prescribe.

I take 100mcg T4 + 25mcg T3 together, before bed as the combination means I'm not kept awake by palpitations I suffer on T4 only. If you can't sleep, switch to morning dosing.

Thankyou for your replies, I think I get it now appreciate all you help, have been on Levo for 28 years and still had hypo symptons but didnt realise there were other meds even if you do have to source and purchase yourself.Just hope that something else works as want my life back, especially as my husband has only just survived major cancer op, we have dreams to fulfil.

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