Could anyone remind me of the approximate equiv... - Thyroid UK

Thyroid UK

141,244 members166,489 posts

Could anyone remind me of the approximate equivalence between T4 and T3

Steni profile image
14 Replies

I remember reading that there was a rough formula for this.

Having started on T3 over the last couple of months I have gradually arrived at a dose which initially felt like magic! Sadly it only lasted for 2 days and although the dose is still the same (3 x 20mcg Thybon) symptoms of constipation, afternoon tiredness, and cold shivers have returned. I am not basing my dosage on test results and I’m being guided by how I feel. Please don’t all say this is wrong.

I am interested to know what my 60mcg is equivalent to in terms of T4 just out of interest.

Written by
Steni profile image
Steni
To view profiles and participate in discussions please or .
Read more about...
14 Replies
greygoose profile image
greygoose

There are all sorts of theories - x3, x4, etc. But, the truth is that it depends how well you convert. If you convert well, could be that 60 mcg T3 = 180 mcg levo. If you convert badly, it could be a hell of a lot less. I don't really see the point of trying to convert. It's like when we converted from £, shillings and pence to decimal. People frantically trying to work out was £1 12s and 6 pence was in decimal. Does it matter? The price is the price. :)

Steni profile image
Steni in reply togreygoose

Your right as usual😂

greygoose profile image
greygoose in reply toSteni

Thank you. :)

Apollo_Creed profile image
Apollo_Creed in reply togreygoose

greygoose could you speak to the point that Steni raised about an increase in dose leads to a magic feeling then drops away? I've seen it said that this is due to the dose not being high enough. Is that the case, and if so, does it require an increase?

greygoose profile image
greygoose in reply toApollo_Creed

Usually, yes, it does. It is quite natural to feel well after an increase in dose, because the body reacts to having thyroid hormone after being without for a period of time, but then realises that whilst welcome, it's not quite enough, and the symptoms come back again. And, you go through this proceedure until, one day, the symptoms don't come back, and you know you're on the right dose. :)

in reply togreygoose

That has been my experience, it's like riding a very slow switchback. You feel better after a week or so, then level for a few weeks, then some of the symptoms come back again. I was worried when that first happened, but folk on here gave reassurance that this was what usually happens.

Also, the starting dose usually has to be very low (25 or 50mcg) and, at the beginning, you might even feel worse than you did without any treatment. The reason is that the external supply of levo causes the thyroid (which is already struggling) to decrease its own production. But when you are near the right dose that won't happen so much.

But everyone is different. The main thing is not to give up, learn all you can about your condition in order to go for the treatment you need.

Steni profile image
Steni in reply to

Really interesting to hear this - I had more or less come to conclusion that I was needing to lower the dose, it’s scary doing this on your own without the benefit if blood tests but as my gp is without the slightest bit of knowledge and I have the brain span of a knat , between us we get nowhere. So when I read that there are people who judge their dosages for themselves based on how they are feeling I decided to try it. As I said previously I’m on 60mcg of T3 and all the symptoms are as strong as ever. I am thinking what to do next, increasing after only 5 days at this dose seems a bit soon......

greygoose profile image
greygoose in reply toSteni

It is a bit soon. You should wait at least two weeks between increases.

Steni profile image
Steni in reply togreygoose

Thank you - I will wait 🙂

in reply toSteni

Remember, I was speaking as someone who has only ever been on Levo, not T3, so don't be surprised if your experience is different. Changes in T3, being the active form of the hormone, is, I think, much quicker to cause a change in symptoms and needs to be adjusted in much smaller doses. T3can be tweaked (by tiny, cautious amounts) after a couple of weeks, instead of up to a couple of months that Levo needs.

That right greygoose ?

greygoose profile image
greygoose in reply to

I'm not sure that T3 is quicker to change symptoms. I never found it that quick. However, as I was so awful on levo, no matter what the dose, T3 had to be an improvement. But, as you say, we're all different. :)

Steni profile image
Steni in reply togreygoose

I couldn’t agree more re the dreadful Levo

greygoose profile image
greygoose in reply toSteni

I refuse to knock levo, because some people do very well on it. We don't want to put new people off trying it, do we? They might do well on it, too. It just didn't suit me, that's all. But, as everyone that knows me will tell you, I'm just odd! lol

Steni profile image
Steni in reply togreygoose

Very true - I mean about the Levo!

Not what you're looking for?

You may also like...

T3 to T4 equivalence question

I have been on T3 only now for around 10 weeks after previously being on T4 for 17 yrs, and then...
Agapanthus profile image

The relationship between Tsh and T4

I hope this isn't annoying as I am still trying to learn this and understand better. I understand...
Obsdian profile image

T3 and T4

Hi all Happy New year! I have recently started taking t3 alongside t4, has been t4 only for 30...
Topes009 profile image

T3 and T4 dosage

Hi everyone, Doctor is trying me on T3 with T4, but he has not lowered my T4 dose of 125, and given...
Nellups profile image

T4 AND T3 together ?

Hi all, i take 75mcg T4 and 10mcg T3 together at 6am with a glass of water every morning and don't...
Jodiedebs55 profile image

Moderation team

See all
Jaydee1507 profile image
Jaydee1507Administrator
PurpleNails profile image
PurpleNailsAdministrator
SlowDragon profile image
SlowDragonAdministrator

Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.

Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.