Getting used to T3

Hi all, I just wondered how long it generally takes people to get used to t3 when swapping straight from t4? Day 5 for me - took more than half of my 20mcg at 6.45 because the tablet didn't split straight and my heart rate is now 78 when it's normally about 50 and i feel a bit shaky.

Jury's still out so far, sometimes i feel better, sometimes worse. I went for a short run last night and couldn't catch my breath and my heart was pounding.

Any reassurance would be much appreciated!

Thank you,


37 Replies

  • Oh and sub question - do people monitor temps and heart rate etc to know when the next dose is due, or just take it eg 8 hours later if you're generally awake for 16?

  • Hi Mountaingoat. Have you read Paul Robinsons book called Recovering with T3? His face book support group link is below:-

    Am afraid I'm probably not much help as am on a combination of thyroid hormones -NDT. But hopefully someone else will respond who knows more about taking T3 only or you find the above link helpful.

  • Thank you very much, I have heard of it but not read it - I will look into it and check out the FB group.

  • Thankfully, I'm fine on T3 and have had no problems at all. I took my temp/pulse initially before I began T3 just to monitor things I don't now unless I feel a bit 'off'.

    I take one daily dose and lead a normal life.

    If you been on levo previously it usually is a straight swap-over to T3. The dose has to be sufficient for us to function for the day at least (the effect of one dose can last between one to three days).

    I noticed you went for a short run last night and if we exercise before getting to an optimum of any thyroid hormone replacements we have to do 'gentle' at first whilst introducing/increasing dose.

    Because T3 is the active hormone required in all of our receptor cells exercise depletes the T3 more quickly.

    Supplements etc are also important.

  • Thank you Shaws. I would love to be able to take it once a day, but I'm definitely not there yet!

    Re the run, I am a regular runner and although it can be hard work sometimes, shortness of breath/a madly racing heart is not something I normally struggle with, it's been more lack of energy - that's why it scared me a bit.

    I am considering some iron, as my levels are a little low, but I'm also not sure about changing too many things at once as I won't know what's working.

  • It's not always easy and I've had some ups/down as well. Particularly when I thought I was getting symptoms again. I have kept a note for a while now if anything extra/unusual develops.

    Last time (a year ago) I was quite puzzled and having unpleasant symptoms because I had been taking T3 for a while amongst them was lying down the room went round. plus some other things until a member posted about a particular batch No. Mine was the same so switched to another T3 and have been as right as rain since (touch wood). So there had to be some change to the fillers/binders in the batch which wasn't in the previous lot although the manufacturer says there was no change. I don't believe that particularly if others also complained. I know it wouldn't be the liothyrone (or levo if you take that) but the fillers/binders it has to be.

    I increase by 1/4 at a time so that it is easier to drop down by 1/4 rather than half and I have been on doses which include the 1/4. Sometimes you only need a small amount to make a big difference.

  • Wow, it's a minefield isn't it! My tablets are so tiny I think I'd struggle to split them into quarters. Also the bottle doesn't have a batch number on so I wouldn't be able to keep track of that. Do you get yours on prescription, or order online?

  • GP (and also have mine I bought on holiday - as sometimes UK runs out of T3). UK only has one licenced T3 and I think it's price has increased by 4,000% I believe. No wonder doctors don't want to prescribe.

    It is a minefield as you say. One might suit you and not me. I think it's because we're dealing with hormones and not a headache when you'd take a nurofen or paracetamol and are 'cured'. :)

  • Oh if only it was that simple!!

  • When your chemist takes your t3 from the original tub and puts them in a bottle he should also give your the PL from the original tub so you have the batch no and date of expiry.. Boots used to do that for me so I went to a private chemist and get them in the original tub.

    Jo xx

  • Thank-you Shaws, I keep learning more and more from you.

  • Hi Shaws, I just wondered, does your heart race and you feel a bit wobbly about an hour after you take it for an hour or so? I don't really like this feeling but wonder if it won't always happen.

    Thank you x

  • My heart may jump slightly for a second or two but that's not unusual. My heart doesn't race nor do I feel wobbly. I wonder if you drop your dose by 1/4 and see how you feel. You could be taking a 'little' too much. These are two excerpts:-

    1. Let me explain the error in the Internet doctors’ thinking. Within a couple of hours after a patient ingests a single daily dose of plain T3, the blood level of T3 peaks. The Internet doctors infer that because the blood level of T3 peaks, the metabolic reactions of body tissues also peak, resulting physiological instability. Their inference is wrong.

    The origin of the doctors’ erroneous thinking may be the reaction of the heart to T3 in some individuals. In some patients who take a single daily dose of plain T3, the heart rate slightly speeds up for a short time. The speed up results from a direct effect of the T3 on heart cells. Avoiding this increase in heart rate in patients with fragile heart conditions is prudent. However, in the vast majority of patients, the increased heart rate is transient and harmless. This is especially true for patients who take heart-protective nutrients and engage in regular cardiovascular exercise. (I have written more on about the effects of T3 on heart function.)

    2. In some cases such as yours, the patient's Cytomel dose may need to be reduced. But symptoms such as occasional heart pounding and anxiety are usually not due to a patient's Cytomel dose. I say this because when Cytomel is solely responsible, symptoms of overstimulation are consistent, not occasional.

    However, it's important to consider whether a patient's Cytomel dose is high enough to sensitize her to other stimulating chemicals. (Examples are caffeine in coffee, theobromine and theophylline in chocolate, and ephedrine in cold medicines.) If the Cytomel has excessively sensitized her to such chemicals, then when she consumes them in foods or medicines, she'll experiences transient symptoms of overstimulation. She'll be overstimulated for a few hours, but then the symptoms will disappear. The Cytomel will have also excessively sensitized her to her own adrenaline and noradrenaline. Because of this, emotional arousal or intense exercise might also cause temporary symptoms of overstimulation.

    The proper solution to occasional symptoms of overstimulation is to find the causes and correct them. The patient's may have to reduce her Cytomel dosage low enough to relieve excess sensitivity to stimulating chemicals. And she may have to reduce her intake of such chemicals. In general, though, the proper approach is not to take the patient completely off Cytomel—not when it has relieved her troubling and disabling symptoms.

  • That's so helpful, thank you. It doesn't last long (fine again now) so I think I'll stick with 20mcg for now and see how I go, esp as taking one tablet once a day is so much easier. Not sure if anyone saw my comment below about my chat with the pharmacist, but I certainly found his explanation helpful.

    Many thanks as ever for the support.

  • Hi Em,

    this is just my personal experience of being on t3. T3 has worked for me personally within hours. This is my second time on t3. The first i was multi dosing but was not very successful at timing my doses and suffered peaks and troughs.

    This time i take just one dose in the morning and have slowly built up listening to my body and only increasing when the fatigue and body aches start again.

    I know by experience that i cannot utilise any t3 if i have t4 in my system. I found this out after we introduced liquid t4 to counter balance the troughs. This made me very ill again and for weeks after t3 just wasn't working so i gave up and back to no meds. Tried NDT somewhere within all this and same happened. On both occasions starting t3 i had been off thyroxine for many weeks so my body was clear of it.

    Had i taken t3 directly after finishing t4 i think it would not have worked and would have given up trying to take it.

    Started back on t3 again after 6 weeks or so of being very symptomatic. It's 24 weeks now and i have my life back but remember we are all individual and any thyroid meds work differently for people.

    I personally have had to experiment a lot and there's been a lot of trial and error along the way.

    My advice is take it very slowly, yes take your pulse, blood pressure and temp as this is a good indication of whats happening.

    I personally have felt if I've been a little bit over when the weather was warm and reduced to suit.

    Hope this helps a bit and remember if you decide to give up because you don't think it is working then perhaps leave it a few weeks to let the t4 leave your system then try again.

    Good luck Sparkly x

  • Thank you so much for sharing your experience, that is really helpful to me. As it's only day 5, maybe I need to give it a bit longer to get rid of the T4 completely and then see how I feel.

    It's interesting how many people say that take T3 once a day, vs lots of websites saying you need to split it. I would like to be a once a day type, although from what I've read an empty stomach is not as important with T3 which makes multiple doses slightly less faffy!

    Thank you again x

  • I think the majority of people just swap over without any problems but i don't think i am one of them.

    Yes once dosing is brilliant for me but my consultant who i saw on friday would like me to split my dose, but tbh i'm a bit scared to change what works.

    You might find you'll need to experiment a bit and find which regime works for you. Some people also take just one dose before they go to bed at night. Like i said it's all a bit of trial and error so don't give up to easy. X

  • Thank you, I won't :) Why does your consultant want you to change? I'd say stick to your guns if you're feeling well! Were you advised to do once a day initially, or did you just try it yourself? x

  • My consultant thinks i might be over medicated in the morning ( i don't feel it) and under in the evening.

    Under does happen when i need an increase but i just take this as my sign i need to up my dose.

    Once only was something i had read and knew Shaws does this.

    When i restarted t3 on 6.25mcg i just went with the flow. As i didn't feel the need to take another dose that day, so i didn't, nor the next or the next. 4 days before i felt the need to up to 12.5mcg and this is how I've worked it for the past 24 weeks.


  • Ah ok, that makes sense. Thanks for sharing x

  • If one dose works for you don't change. Endos know little about how T3 works in our body and it's a bit of a 'guesswork' when treating patients. They imagine it has peaks and troughs but it doesn't as one single daily dose saturates our receptor cells and the effect of that dose lasts between 1 and 3 days.

  • Thanks Shaws, well i can now tell him I've tried it (again) and as i knew by 5pm i was floored with tiredness and had to sleep.

    To rectify this i need to take the full dose i took in the morning, i have tried just topping up but this does not work.

    Once only dosing for me is a must!

  • Maybe he needs a little more knowledge. The site below was by a doctor/scientist/

  • Hi sparkly, does the advice from my pharmacist that I've added at the bottom of the page help? x

  • Mountaingoat, T3 can bind with proteins in food so it's important to observe 1 hour before or 2 hours after food/drink and away from other meds and supplements.

  • Hi Clutter, is UK T3 different to Cytomel? Just that I was looking at this website and a couple of others which said it was ok with food. Excuse the ignorance!

  • Mountaingoat, the active T3 will be the same but the excipients will probably be different.

    I can't find the link to Dr.Lowe's article which advised that T3 binds to proteins and should be taken away from food and drink.

  • Dr Lowe took his T3 once daily at 150mcg (he had Thyroid Hormone Resistance) in the middle of the night. He did say that food can interfere with the uptake. He was also a scientist as well.

  • I started on multi-dosing, being very, very cautious, and using tiny dose sizes. I only increased by 1/4 tablet at a time, and if it didn't work well I dropped back again for two or three weeks. I'd had heart issues for a few years so I thought being cautious was a good idea for me. My heart feels better now than it has done for years.

    I've very recently started amalgamating just two of my doses and I have to say the early signs are good. I feel more energetic and my brain feels clearer.

    If you don't feel right on the dosing pattern you are currently using then experiment until you find what works for you. I experimented with my dosing pattern and dose sizes every time I changed my dose. I stopped worrying about what was considered "the right way" to do things, and just worried about what worked for me. I've had no regrets and it has proved to be a good plan for me. :)

  • Thanks for sharing your experience. How on earth do you split one of these microscopic tablets into quarters?!

    My heart still feels a bit quick this afternoon, but then my resting pulse was 39 before so maybe it's more like normal!

  • I use a scalpel with replaceable blades. They can be bought for less than a fiver from Amazon. I've got better at cutting my pills with practice.

  • Ah right, I need some new tools!

  • You can buy a pill cutter, a little plastic container that cuts the pill and keeps the little pieces safely enclosed - instead of them flying off around the kitchen!

  • Thank you, that's what I bought but it doesn't always split them down the middle. Sharp knife and chopping board did the trick last night so I've done a few days's worth. Just an airtight pill box to carry my pm dose in now.

  • When I have to split a t3 pill I just use my thumb nails.

    Jo xx

  • Thank you so much to everyone who has given me advice, it is much appreciated.

    As an update, I didn't have a great day yesterday, really hit the wall at lunchtime and sat through a work meeting like a zombie waiting for the next dose to kick in and feeling awful.

    Decided to speak to my local pharmacist who is very knowledgable, and he very kindly took the time to sit with me and talk through my concerns. A key thing for me that he explained was that the amount of t3 in each half tablet will never be exactly half, so one dose might be 15mcg and the next one 5, or 20 and 0 etc. So maybe yesterday morning's dose was lower. His view was that I should take it once a day, and when I asked about half life he drew me a helpful graph to explain how t3 will build up with each dose so after a few days one dose is ok - I haven't done his explanation justice here.

    So took a whole 20mcg this morning and hopefully I'll make it to tomorrow morning in one piece!!

    I hope this helps others too x

  • Sounds like you have a very knowledgeable pharmacist. Most probably knows more than most Gp's.

    I'm sticking to my once a day dose as i know for definite it works for me.

    My bloods are ok so i'm not worrying. I'll just carry on listening to my body.

    Only we can feel how our body responds to medication.

    So go with how you feel and chop and change accordingly.

    This is just my experience only.

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