I know there's a ratio for T3:T4 production in the body. Should your doses of thyroid replacement reflect that ratio exactly? If so, what is the ratio in humans? I'm on 150mcg levothyroxine and 15mcg liothyronine. At my last blood test my T3 was high but the endocrinologist told me if I feel good on this dose (which I do although I preferred being on 20mcg as I ate less and I feel like my mind was sharper) then I should keep it as it is and retest in 3 months. I'm a bit confused because the rest of his team told me I need to lower my liothyronine dose until my TSH is back within normal range. He's the head consultant and he contradicted what the rest of the doctors I had spoken to previously expressly told me. Should I be worried...?
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Zazbag
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I am on 50 mcg of Levothyroxine and 5 mcg of Liothyronine. That makes your dosage in line with mine.
Don’t know what the correct ratio is. My endo won’t change the dose even though I have been told my dose is too low, he says since i feel fine, the dose will remain the same.
Must have misunderstood your previous reply. I thought you took 50 mcg of levothyroxine and just one pill of 5mcg liothyronine. Thnxs for the quick response either way.
There is no correct ratio for hypos. In fact, ratios have nothing to do with hypo, they are for healthy people. Being hypo, you need what you need. If what you need is T3 only, as I do, then so be it. Don't allow yourself to be manipulated by being compare to a euthyroid person. It just doesn't work like that.
My only concern is whether having high T3 is thinning my bones. But even on 25mcg I felt great (although I got angry very quickly and had heart palpitations a lot haha).
Do you mean your dose of T3 is high? Or your FT3 is high? If the latter, how high? Remember, the FT3 level just tells you how much is in your blood. It doesn't tell you how much is getting into the cells. And, it doesn't do anything until it gets into the cells. So, even if your FT3 is over-range, it doesn't automatically mean you're taking too much.
I take 75 mcg T3. That is the correct dose for me. I can't tolerate it any higher, and reducing it brings back hypo symptoms like anxiety - always the first one for me.
Getting angry and having palpitations can also be hypo symptoms. And, it's possible to be taking a high dose of T3, and have over-range FT3, and still be hypo if the T3 is not getting into the cells.
On 17.5mcg my last blood test was FT3 8.1 (range up to 6.8).
Oh okay, that must be why the endocrinologist was okay with it.
In all honesty I felt better before on a higher dose but I listened to the doctors in his team who were insisting I will give myself osteoporosis and atrial fibrillation if I continued.
Can you really just dose yourself based on how you feel? I had a lot more motivation and energy and focus and ate less and was losing weight when I was on around 20mcg. I feel good now but my weight loss has stopped and I have less motivation/energy than before and my mind isn't as sharp.
How would I know whether the T3 is getting into my cells?
The only way you can know if the T3 is getting into your cells is by how you feel.
But, 20 mcg T3 is not a high dose. It's high enough to suppressed your TSH, though. And, doctors are terrified of a suppressed TSH. So, they put the fear of god into their patients, at the cost of their well-being. It's the FT3 the most important number, not the TSH. But, even so, the ranges are just a rough guide and not set in stone. How you feel is equally important.
I'm surprised that just 17.5 mcg T3 took your FT3 so far over range. How long did you leave between your last dose of T3 and the blood draw? Do you have Hashi's?
OK, so the timing was right. But, it's possible that that high FT3 had more to do with a Hashi's swing, than your dose of T3.
Don't reduce your T3 just to increase your TSH. Your TSH is low because you don't need it when taking T3. So, don't risk making yourself sicker in order to raise it.
I take 75 mcg T3. That is the correct dose for me. I can't tolerate it any higher, and reducing it brings back hypo symptoms like anxiety - always the first one for me.
Okay I understand. So if I feel more tired and brain foggy and less motivated and hungrier and more depressed on 15mcg can I assume that I need more liothyronine? I feel good but I felt better before on 20mcg.
So I've taken 20mcg of liothyronine the past two days instead of 15mcg and my mood is much better! Like how it was before I lowered it where I'm smiling all the time for no real reason and feel motivated to do stuff I'd rather avoid. I think I will stay at this dose and just monitor for heart palpitations.
Excellent. I've been following you carefully as I'm on the merry-go-round of trying to find the right dose of T3 and Levo. You were on too much at 25mcg I think because of your sudden switch in mood/anger etc. But you were so much brighter in yourself (from your written posts) on 20-22 T3.
The risk of oestoporosis and arrhythmia are there, but from sustained overdosing of T3 and that feels horrible from what I've seen here and is unlikely to be something you want to live with. You just have to switch them off when they go on about it. I had Afib long before I was diagnosed hypo, Levo has never made me feel well. I introduced T3 a couple of years ago and at just 12.5mcg my Afib became persistent. I reduced to 6.25mcg immediately. No difference. When I saw a cardiologist he tried to scare me off the T3 completely (it worked) and I've been really sick for the past 2 years. I know he was wrong. I have Afib and a high heart rate all the time now. I've recently added T3 back in with the help of a private endo. I'm sticking with it. It's not the miracle cure for me yet. I'm on 25mcg with 125 levo, which I have started to increase to 150 today as my last bloods showed both T3 and T4 in the lower 40% of the respective ranges. I went up to 25 T3 and now I'm adding in extra T4 to see how it goes.
I'm starting to think Endos currently working in the NHS have very little understanding of this. I am far more worried that my Afib will degenerate a lot more over time with low T3 levels. The heart and brain are the biggest users of T3. And I will definitely have issues with my bones because unless I find my energy again I've become an exhausted couch potato. I take HRT to help protect my bones and I hope one day to find the magic dose of Levo/T3 to get me back out walking those fields and riding my bike. Don't be scared of those conditions. Go by your mood.
Wow I can't believe you noticed my mood changes from my T3 dose modifications hahaha. You're right, I think 20mcg is my sweet spot. I went up to 25mcg hoping I could get away with that because it's so much cheaper to use 50mcg tablets than 5mcg. But yeah unfortunately it made me very angry and I had heart palpitations. I'm going to ask for a DEXA scan. I'm sorry you're having sustained issues with AF and getting the right dose combination. Have you tried 150mcg levo?
Without T3 150 levo took me over the top of the range, made my T3 go down and I felt horrible. Adding T3 has really lowered my T4 results so I raised my T3 to 25 2 weeks ago and got settled on it and now today I have increased my Levo to 150 to see if it will help me.
Living with persistent Afib is a LOT easier than living with the sudden, out of the blue, violent and crippling unexpected bursts of lone AF that happened about every 10 months for a few years leading up to it. My Dad had AF badly for many, many years. I seem to have inherited. But seriously my thyroid is much worse because I have no energy and can't live my life properly without it.
This is useful to know. I wondered if I was taking too much T3 (waiting for blood results) as I also re-added Levo due to “crashes”. So many symptoms cross over between hypo and hyper; is Hr a good indicator of over medication? My average resting Hr over a 24hr period is between 44-49 🤔
That's a low resting heart rate. I can't use heart rate to help me with thyroid as mine is running fast around 100bpm even with a beta blocker because I am in persistent atrial fibrillation. I noticed that when I first started T3 my heart rate went down into the 80's when I took it. That felt a lot better for me. But it didn't stay down there so I'm hoping when I find the right dose it might return there for me.
Okay so this noticeable improvement in my mood has stayed constant since I increased to 20mcg. I feel great. Definitely staying at this dose for the moment. Thanks again for your advice!
One of the problems in even trying to think about a ratio is absorption.
Imagine someone taking 100 T4 and 10 T3. (Just to keep the numbers simple!)
Typically, it is suggested that T3 is well absorbed – quite often 95% is suggested.
Whereas T4 is variably absorbed with a range possibly from 50% to 80%. (This is a range from one person to another. In one person, it will be a much smaller range.)
If we work this out, the T4:T3 ratio of the tablets is simply 10:1. But what you absorb will be different. In the cases I chose, 8.42:1 to 5.26:1.
That is, even if you knew what ratio you were trying to achieve, it is difficult unless you can assess your absorption percentage. (And that is just a start to the difficulty of applying arithmetic to the issues.)
Ok I am taking 1 pill in the morning of levothyroxine 75 mg and now liothyronine 5mcg 1 pill aday. From what I'm reading this is a very low dose compared to some of you ! I just barley started taking this I sure hope it works. What are some of you taking 15 mcg of liothyronine ? Should i be taking this dose too ?
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Dosage of Liothyronine and Levothyroxine
Is there a ‘common’ T4:T3 ratio
Introduced t4 back in to regime with my liothyronine should I increase dose. 
Is there a shortage of T3?
