Started t3 but not sure if getting the dosing r... - Thyroid UK

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Started t3 but not sure if getting the dosing right


Hi, I posted recently about feeling unwell on Actavis 100mcg. I have since played with the doses of Levo and felt best on 88.5mcg (not alternating as I felt fatigued on days when taking 75). However, the average dose since my blood test at 6weeks on 100mcg (just over four weeks ago has been c. 95mcg). I was feeling pretty well at that point. I believe I'm very sensitive to dose changes, up,or down, tend to feel it within hours rather than days/weeks.

I decided to add t3 at quarter of 20mcg tablet so taking 5mcg of t3 and 75mcg of Levo. I felt really well the first 2 days but late in the evening of day 2 my heart rate shot up and I stayed practically awake and restless all night. I took only Levo that night/morning. That day my heart rate was extremely low, the following morning at my lowest ever pulse of 44bpm just as I woke up (I wear a Fitbit monitoring my pulse 24h). I took the Levo 75mcg+5mcg of t3 combo yesterday and today but I have not been so well - I'm tired, have brain fatigue, 'near misses' of palps (they used to be quite common before diagnosis and gradually stopped as Levo was increasing), my leg muscles feel sore and numb in the evenings but my heart rate is on the low side.

I cannot work out if I may be turning more hypo as the t3 is not enough to make up for the reduction in Levo or the opposite, have I got the conversion wrong and am now taking too much? Or is it normal to need to adjust to the t3 and it will eventually pass? Or shall I go back to Levo for now and try t3 at a later stage?

Your views will be highly appreciated! Thank you.

12 Replies

It sounds like adding the small dose of t3 to your levo initially gave you a little spike of hormone and you overcompensated by taking no t3 at all. Do you know if you have a conversion problem? If your levo isn't doing you much good you could have gone quite hypo on the day you missed out your t3. (I hope I got the gist of what happened. Sometimes I read too quickly. :-) )

Do you have your last blood results? It might help illuminate what's going on.

I think there was a bit of a difference of opinions regarding this. At 6 weeks on 100mcg my tsh was suppressed and ft4 overrange, ft3 was 5.8 (range to 3.1-6.8). As my ft3 was just in the top part of the range I was told that I was converting well but in a later post, when the timing of my last dose of Levo prior to the test got attention the conclusion was that I was not converting so well as the ft4 reading would have been c.20% higher due to a longer than 24hr gap yet the ft3 would have been unchanged. So possibly I had rt3 coming into play?

I decided to go with the conclusion that my conversion wasn't ideal and I always intended to give t4&t3 combo a go anyway.

Yes, fair enough, for some people (I'm one) it is immaterial as conversion may look ok and t3 can still make a difference when taken in addition to levo.

Sorry, I think I thought you added an *extra* quarter of a tab but I think it is just that you started your t3 w a quarter of a tab, felt better for a few days and then felt overstimulated - ?

As helvella says, if you're very sensitive perhaps the change required needs to be more nuanced. It is a devil of a thing: I feel much better w some t3 added but it does make the whole situation rather more three-dimensional than it was on levo alone.

I wish you luck.

Yes I replaced 12.5mcg of Levo with 5mcg t3. I felt fantastic for 2 days but just before midnight my heart went mad and stayed fluctuating at high levels all night. It did scare me as I'd not experienced it before (much milder form of it when I started to feel unwell on Actavis 100mcg) and didn't want to make it worse by taking another dose. But despite feeling awfully tired I was not too bad so after 1 day's break I started on t3 again. But now feeling v tired, with brain not quite foggy but can't concentrate much on anything - these also were my worst symptoms before diagnosis.

Thank you🙂

My only other thought is that this could be a cortisol thing. If you take your dose of t3 first thing in the morning it seems unlikely it would suddenly kick in at midnight. But if you have high cortisol at night (ok I'm on shaky ground here as this is not my area of expertise :-) but I think this is correct) I believe this is when you can find yourself waking w a pounding heart or having trouble falling asleep. (I do hope someone else who knows more about it will come and confirm/deny.)


I believe it is impossible to know exactly what effect taking some T3 will have. We see people doing anything from making no change to their T4 at all, through to assuming something like 5:1 - so for 20 micrograms of T3, you'd drop T4 by 100. That is, as much or more than you are actually taking in the first place!! Or for the 5 micrograms you took, that would be a drop T4 by 25 micrograms.

The appropriate change is quite possibly a smaller reduction in T4 than you have made. I suggest trying somewhere around 80 to 85 micrograms of T4 plus 5 micrograms of T3. That is, closer to 3:1.

In the end, you can try to work it out forever, it is what actually works that is important. You sound to be a bit under-dosed. Try a small increase.

Remember that changes like this will continue to ripple on for a long time. You might find a change feels good for a short while, then starts to feel wrong.

(I tried alternating 100 and 125 - and did not feel right. Am far happier on 112 every day.)

Sybilla14 in reply to helvella

Thank you helvella. It was actually inspired by you, through reading your past posts that I gave 88.5mcg a go as I felt too low on 75 and a bit too much at 100 even just on alternative days🙂.

Following your recommendation, helvella, I increased the t4 to 81.25, 88.5, 88.5, 81.25 over the last few days along with the 5mcg t3. I was ok for two days but yesterday I felt really hypo, in the morning I even suspected I may be coming down with a virus as I felt so tired and wanting to rest/snooze. My heart rate has been on the low side, resting rate at night averaging 53bpm over the last week. Then Sunday night, about 10.30 as I was setting for the night my heart rate started going up and down. It really did feel like anxiety, my stomach was knotting with thoughts racing, then calming down again. I stayed up till 3am and managed to fall asleep only after I remembered that I had some beta blockers in my medicine cupboard (prescribed by a sympathetic gp about a decade ago to help me with the stress of flying after a particularly bumpy journey...). Woke up about 5.30. Yesterday I was very tired, though not particularly sleepy, low heart rate throughout the day (c. 50 when sitting at my desk for a short while).

I think that puncturedbicycle's suggestion of adrenals being to blame makes sense however I would be inclined to suspect my cortisol would be low rather than high. I think I had high cortisol some 5 years back and burnt out to a rock bottom about 2.5 years ago when I made concerted efforts to get healthy by paying attention to diet and supplements, etc. However I do think that adrenaline kicking in because of weak thyroid output has been troubling me for about 3 years, manifesting in night sweats (subsided on Levo).

I'm completely lost as to which way to turn. Could adding just 5mcg have such negligible effect that by reducing the t4 slightly I caused underdosing? Or am I not taking enough t3 or at the wrong time of day so during the day, as it wears off I get hypo? I took only 88.5mcg of Levo this morning as the way I've started to feel was bad but maybe I ought to try taking it late morning?

Any ideas are very welcome. Thank you!

Off the top of my head I wonder if you should try 10mcg t3. If your pulse is in the 50s you can't be overmedicated. I experience sleep disturbance/insomnia when hypo.

Imo (as a layperson) 5mcg is a good start but if you need t3 enough to go to the trouble of getting it you probably need more than 5. Anecdotally I don't recall reading here that anyone stays on 5 because it makes them feel so fantastic. It is usually a starting point.

If you find you're feeling improvements on more t3/less levo, maybe keep going in that direction. You may be one of those who feels better on t3 only.

As you seem to be a bit sensitive to meds it seems a good idea to try something, make note of how you feel and (barring any serious symptoms like racing heart) stick with it for a while. Levo (when raised or reduced) takes weeks to level out but t3 is more immediate. Do you keep a symptom diary?

Thank you🙂 Apart from the anxiety like heart racing at night I have no symptoms that I didn't have when being undiagnosed/undermedicated. I got a Fitbit in preparation for trying liothyronine to monitor my pulse as that reacts to THs - it measures all the time and does a daily average - it is 51bpm today (right now 54 and was as low as 40 before I got up this morning) and was 59 for 2 days when I took my 1st 5mcg of t3 and it was the highest average so far.

I actually took 5mcg at 11am (88.5 of Levo at night) as I had it with me and felt good at first but feeling a proper afternoon slump now☹️. I'm planning to take 10mcg tomorrow morning and 81.25 of Levo at night. Fingers crossed I'll get to feel balanced soon!

Yes, fingers crossed! Good luck. :-)

No, that's one thing I've been hoping to get away with 😉 I write down all the pills incl brand every day but as I've been reacting immediately to doses I kind of logged in my head how I felt when. My biggest issue of all is cognition and tiredness/malaise, occasional palpitations (like a stalled heart beat) and night sweats are a major barometer. Other symptoms I notice but don't pay that much attention to as I can live with them so to speak. Although I was starting to feel good on Levo, I experience great clarity of thinking when on t3, which I've not had for years🙂. So, on the right dose I could do on Levo alone but I believe there is a reason why a thyroid gland does not just produce t4 and so always intended to try some. Now that I have and can see an improvement I'd like to keep trying to get the doses right. Perhaps you are right, I should start recording my symptoms to be sure 🙂

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