Thyroid UK


I know that many people on this site are on T3, myself included. I just wondered if anyone is taking a higher dose of T3, than T4, where people are currently on a combination of T3 and T4.

I currently take T4 150 and T3 50. I am considering either going on to T3 only or to lower T4 and see what works best. However, when I was diagnosed hypo I have primary overt, not subclinical, so am assuming that I would need some T4?

27 Replies

Pink, there are people taking highish doses of T3 with just 25mcg T4. It doesn't make any difference whether you were overt or subclinical when diagnosed as to whether you need T4 or not. There is some research suggesting T4 is more than just a prohormone and may have other benefits. I haven't bookmarked it so I can't link to it. As you'll naturally produce some T4 if you have a thyroid gland it doesn't have to come via synthetic Levothyroxine.

I can't tolerate T4 only and I prefer T4+T3 combination to T3 monotherapy. I don't have a thyroid so I do want synthetic T4 and I like the security of knowing I have about 7/8 days T4 stored in my system should I be unable to take thyroid replacement for a few days.


I don't know if this link will be helpful but go to the date July 12, 2010 to read the questions/answer. The other questions could be helpful too. There are other topics at top of page which may interest you:-

Also an excerpt from within this page:

As a result, a single dose of T3 will be long gone from the patient's system before he or she experiences most of the benefits of that dose—a molecular and metabolic yield that may smoothly spread out over one to three days.

1 like

thank you for sharing this link, I have found it most helpful and interesting.


Thanks - I have saved the link and will have a proper look at this


How are you feeling? With a t4 /t3 ratio like that I would put money on your reverse t3 being through the roof !

I was on 150t4 and 60t3 I am only just noticing the positive effects of t3 having stopped t4 completely and waiting for it to clear , currently on week 9


I am glad you are feeling better on T3 alone.


Thanks Shaws , it's early days but as a lot of people on here I came back with low morning cortisol , thankfully the endo decided to put me on T3 only so I didn't have to go it alone or lie at every consultation


Yes Stuart, it is good your Endo has prescribed. Pass his name to, if you haven't done so, email for her list.


I would be most grateful if you could PM me with your endo's name


Have you been told how long it takes to get rt3 completely out of your system? I was on 100 t4 with 40 t3 but feeling gradually worse until I felt like I was back to where I started, pre-diagnosis. Not due to see my endo till February, so decided to do my own rt3 detox and stopped my t4 completely, gradually replacing it with 40 of t3. Definitely feeling better (now on week 8) but not sure how long I'll be able to get prescriptions frequently enough to keep this going as my GP will notice sooner or later. Will have to go back to something like my original doses before seeing endo, though I will tell him what I've been doing and how it has affected me.


When I told gp that I was taking 150mcg of T4. He said that it would take one month to clear it from the body. He didn't ask how I got hold of that amount, as I am only prescribed 100mcg, which they keep trying to lower to 75mcg, despite me being symptomatic. Also, am prescribed 20mcg of liothyronine, however, have a plentifull supply of that also, which never came up in the conversation with gp.

From what I am seeing, a lot of people are doing much better on T3 alone, which is why I want to give it a go. Though, if my rt3 is very high which I suspect it is - hadn't heard of rt3 till I came to this site, and do my own research now as well to back things up, then from what I understand, t4 needs to be cleared from my body. Will give it a go, see what happens. GP only tests the TSH and mine is undetectable now anyway from combined t3/t3 hence the reason for them trying to lower t4 dosage. Unless they test my t3, which they refuse to do, they are none the wiser. If they test it, I will say what amount of t3 I am taking, though, all they're scare tactics - re 'its dangerous' and one doc even said I was going to have a heart attack by increasing t4 by 24mcg, don't work on me.

For all I know, gp may be giving me placebos to try and clear it without me knowing lol.


Could you post or send me links to any good info you've found about rt3, please? I found a protocol for getting rt3 out of your system which said it takes 12 weeks for it all to be cleared, but can't find the link to it now :(


Had never heard of reverse t3 until I came to this site, but have a look on: and

have been on these sites and there is a lot of good info, however, I couldn't find the protocol you are looking for:-(. If you scroll down the posts, there is a really good reply from Stuartwwhouse, who put it on a week by week basis to understand. Hope this helps:-)


Thanks, Pinkgirl, I'll have a look :)


Ha! yesterday someone here posted a link to the site I had lost. In case it's of interest to you, too, it's . Have it safely bookmarked now!


Thank you for posting the link:-)


Morebeans, Paul Robinson said it can take up to 14 weeks to clear rT3. It took me 12 weeks off T4 plus a week off T3 to clear a build up of T4. I didn't test for rT3 so I can't say it was that.


Thanks, Clutter - had a quick flick through the book and can't see the rt3 info right now, but will take time to search properly later. I'm trying this 'clearout' on my own, so won't have any blood tests to refer to, just going by how I feel. :)


Morebeans, I read it on his website. If you're taking a lot of T3 some members have said they went hyper/over medicated the minute rT3 cleared and had to drastically reduce T3.


Am not feeling too great at the moment, currently off work sick. Am needing around 11hours sleep and physically cannot hold down a job like that, with an hour and half commute and a busy job driving about all day.

Someone else mentioned reverse t3. Had never heard of it until I came to this site. This morning I took 75mcg T3 but no T4, will see how this goes as it's only the first day.


Can you let me know how you have been getting on with T3 alone, I am taking T4 100mcg with 20mcg of T3 I am thinking about goingto 50 of each over the next week and then later in the year trying for 75mcg of t3 in a day wondered how you have got on I two have an hours commute to work and then i drive all day so understand how you feel


I tried this in the autumn but within a week I felt dreadful. I don't think I did it for long enough though to really give it a chance to see if it works. I then after gradual changes tried 200 synthroid with 25 t3 cynomel, and began to start to feel normal on this though I then had bloods done at hospital appointment which showed that I was very overmedicated - see previous posts. I then got lowered to 150 thyroxine and back to 20 t3 liothyronine. The synthroid and cynomel I was ordering myself. Now, following endo appointment am on 200 thyroxine and 10 t3 liothyronine. I am noting that since t3 has been lowered I feel worse and weight gain by 1 stone:-(. Some people need high t3 with a little of t4. For me, I cant do without t4. So a little t4, with high t3 may be the way for me, but others do well on T3 only, also there is some one on this site who does well on t4 only - on I think its 350 thyroxine.

What I did notice was that I felt better on synthroid and cynomel which I cant get in the UK. Currently, still off sick and unable to work.x


I take 112.5 T4 and 30 (split in 3) of T3. When I did a 3 month trial of 70 mcg (starting on 40 and building up slowly) I felt much better. I was at the point that I felt I would have benefited from another 10, but at that point I required surgery and they would not go ahead unless I was taking thyroxine. My endo will not support T3 only even though I felt better on the regime so back on combination above which does not work as well for me. The only down side with the T3 only for me was that I was feeling exhausted in the morning when I woke up so I wondered if 25 or 12.5 T4 at bedtime might have kept me ticking over. I never got to getting it totally right, but if you do increase T3 do it gradually. Good luck.


Thanks to all of you for your replies, it helps me to know what others experience of this is.

Originally, I started out on T4 only, until I saw an endo then got a small amount of T3 added as a trial, however, endo said more T3 was dangerous - which I disagree with and would not increase thryroxine ect so increased it myself and also increased T3 accordingly. Feeling a lot worse and back to where I started before diagnosis - struggling at the gym and with yoga ect - which have been doing since 2003 (was doing 11hours a week then). Currently struggling with 2/3 hours exercise a week.

I am now going to try T3 only, or with a small dose of thyroxine 25, as Clutter was saying, and see how it goes. Like most people, it's a case of trial and error and finding out what works for me:-)


To clarify , RT3 will take 12 weeks to clear

t4 has a half life of 7 days Meaning 50% of your dose will be in your system 7 days later


Week 1 100/2 =50

Week 2 50/2=25

Week 3 25/2=12.5

Week 3 12.5/2=6.25

Week 4 6.25/2=3.125

Week 5 3.125/2=1.56

Week 6 1.56/2=0.78

Week 7 0.78/2 = 0.39

Week 8 0.39/2=0.195

Week 9 0.19/2=0.097

etc etc

It's like folding a bit of paper , regardless how big it is , it will fold exactly the same amount of times

Your doctor clearly doesn't understand how it works

You need all the T4 to erode before the RT3 is gone and T3 has the best chance of getting into the cells

Hope that makes it simple to understand


A big thank you for that. Yes, I can see what you mean. Mmm, they are pretty clueless at my gp practice, they wont have heard of reverse t3 as they barely know what t3 is.

Everything, I learnt about thyroid conditions, I found from my own research of mainly the internet, and when I came across this site, the links, books, journal articles, research info ect and learnt a lot more and am still learning all the time:-)


Unfortunately we need to read it for ourselves because most of the nhs are pants when it comes to thyroid treatment

Have a look at recoveringwitht3 on facebook , it's also brilliant like this site


You may also like...