T3 only not working

Hi all

Am on my second month of Cynomel only and it doesn't seem to be working. Had to stop Levo as developed intolerance - was on 100 daily. Didn't feel well on it for years.

Now am on 25 Cynomel - been a nightmare to get up that high. Every day I feel shaky,anxious, no confidence or energy or concentration. I have lost a stone but was only just over 8 before.

When i try to raise the Cynomel I show symptoms of hyper. I spend most of time feeling really unwell and like I'm on speed.

Is it possible T3 doesn't work for all?

Endo was pleased because he said my thyroid levels are raising but is this a relevant judgment on T3 mono treatment?

Would be grateful if you could tell me what private blood tests i should have which would tell me what's going on.

Am thinking to try NTD - how do I change over please

thanks everyone


34 Replies

I'm sorry you are having a problem with T3. I wonder if it 25mcg is a little too much for you as it is the active hormone and you don't need to convert. If I were you, I would take 1/2 of a tablet and see if this helps and after a few weeks take 3/4 and if you feel overstimulated drop down again to half. You say you were also under 8 stone, so are very light and not need so much.

The mot important thing when taking any thyroid hormone replacement is 'how we feel' and if we feel well we are on the right dose. If overstimulated, we are on too much and the good thing with T3 is if we are taking a little too much, by reducing the dose symptoms dissipate quickly.

Thanks Shaws. Yes I am skin and bone now, so not much to absorb and cant get the weight back on. I will try cutting my dose and also space it for a few weeks like you say. I think the Endos aim for me to get up to nearly 2 tablets must be textbook!

I found raising T3 very hard, until my iron levels and ferritin levels improved. Have you had these tested and if not, whilst having those, ask your doctor to check Vit D, B12 and folate. Deficiencies in these can cause problems but for me it was definitely low iron. I felt hyper, with sweating, aching and very slightly raised temperature. These symptoms would last for several hours after taking a small divided dose and then everything would clear and I would feel fine for a while. Then I would take my next dose and it all started up again. I found chopping up tablets into quarters and taking more frequently the best way to go and as iron levels increased, it became much easier. Eventually I managed to get to 60 mcg, split into 20 three times a day.

There is a very good book called "Recovering with T3" by Paul Robinson, which was invaluable in helping me.

Thanks so much. Yes I will get those things tested as I havent had them done for 6 months and physically I have changed drastically in that time, with being ill and so thin. Would be good if thats the reason I can't raise it (unless I just dont need much)

Yes I must order Paul's book, have seen excerpts and articles written by him and think it would explain a lot to me.

It is interesting that you are very thin, as I am also and got thinner when on T3 only. It is still hard to keep weight on and I always have to be sure to eat regularly. That was one of the reasons for my changing back to the T4/3 combo. My weight is more stable. I am sorry you have been so ill and hope you will improve soon.

Have you tried cutting the pill into quarters and taking 1 quarter every 8 hours? So, reduce dose to 3/4 of a tablet per day?

If you don't take anything for 1 day, see how you feel. If the shakes go away, then re-introduce at the lower dose, see how you feel.

You may not require 25 mcg Cytomel. Dosing, if a person absorbs well, is based on body weight. And not just body weight per se. If someone has low skeletal muscle development, then dose needs to be lower.

that is very interesting about dosing. When I was on 100 Levo I was prob nearly 2 stone heavier than I am now. And my muscles have disappeared since I got on T3, do you think thats why I have lost the weight ? It really is acting like a diet pill ? Thank you so much for your help. Was so ill yesterday I didnt have any and the world didnt end. So I will try again, as you say.

Daffers, T3 is not a diet pill. When people want to lose weight, they want to lose fat, not muscle. Losing muscle is dangerous because not only do skeletal muscles get smaller but the heart muscle is also scavenged for energy. Kidneys require a goodly source of protein and these can fail if they aren't getting enough. This is why people with anorexia nervosa get organ failure. Their kidneys get affected and everything just goes downhill once that happens.

This is the problem: when organs are underfunctioning, of course a person feels sick. It's not just thyroid. You can rev up the metabolism with unapposed T3 and end up with big problems. The dose needs to be adjusted carefully. You've go no ability to make rT3 in order to block excess T3.

Sorry to be a pain, but I have read what you say above and I am quite worried as I certainly didn't want to lose any weight, fat or muscle. this has happened since I started the T3. Do you think perhaps T3 isnt right for me ? I know you aren't a doctor but would welcome your opinion if you could give it to me. I think people on here know more than my endo, that's for sure.

I read that interesting book you posted about, which says we need some T4 as well as T3 which in my ignorance I am hoping to get back to one day. Again, I am worried about making yet another change of meds but hope one day something will suit me.

Thanks again

Just lower the dose for now and see how you feel. If you don't get hyper symptoms then you ought to be alright.

T3 needs accurate titration and you need to be clear about what hyper symptoms are. The shakes and all that are clearly hyper.

You may find that 3/4 of a tablet is enough. You may find that 1/2 a tablet is enough. You need to work with it because it wears off so quickly, you can figure it out relatively quickly. Unlike T4 which sticks around for a long time and takes a long time to build up as well. Since you skipped a day, taking 3/4 of a tablet for the next 4 or 5 days will let you know if it needs to be a lower dose. In a way, this is the beauty of T3. It is a very strong medication. The fact that some people on this forum take huge amounts means nothing. It doesn't apply to you.

Just don't bounce the dose around too much or you won't ever figure out what works and what does not work.

Thanks for that advice. I feel a bit more optimistic now about continuing to work with it and a lower dose might just do the trick!

Although some people do fine taking it in one dose most do best by multi-dosing 3-5 times during waking hours. Are you taking 25mcg all at once? If so you might try splitting the doses up. PR

HI and thanks for reply, I have split it in 2 but prob needs to be split into more as you say. What a nightmare, having your whole life taken over by this.



NO was on 2 doses but am going to split to 3 or 4 as suggested. Thanks

Hi Daffers,

I agree that it's important not to think that there is a much higher dose that you should be aiming for.

I have caused myself a lot of unwellness by aiming to increase the dose rather than listening to my body.

Over the summer I had to cut down from the 50mcg in 3 doses I had built up to over 3 years to as little as 25mcg some days because of the heat and phases of extra physical work. Hot weather and stress make a lot of difference I find. I also take 1 Nutri Adrenal Extra and Ayurvedic Boswellia Formula to help my adrenals.

Sometimes I look at the little white pill I am about to take and marvel at the powerfulness of what it contains. It is strong stuff, and some of us need rather little of it , whereas others, like Dr Lowe need the high dose.

I agree about starting from scratch and building up in small increments, always taking account of symptoms of overstimulation.

Best Wishes, and don't be afraid to give it some time to find how it works best for you.

Hi wildDeer

Thanks so much for your message. I have been trying to ramp it up as the endo said I need to get to 2 tabs per day - and just making myself more and more ill and thin. Its interesting to read what happened to you. I am astounded how powerful it is - even a tiny piece can keep my heart racing and buzzing for hours. and completely make me lose my confidence about things.

I am keeping any eye on temperature and pulse - is that the best measure for overstimulation do you think ?

How long did it take you to stabilise on it ?


Hi Daffers,

I think my situation is that I'm still rather hypothyroid-average basal temp in the morning is

around 36.0 these last months, and pulse around 62 . Then there's whether the T3 that brings me up to a manageable speed can get through to do its job. If I overdo the jobs, and /or there is a lot of emotional stress and/ or it's hot then it's like I'm driving with my brakes on. I can't seem to absorb what I could process before, even with adrenal support.

I have learned that I really can't do as much as I would like to . Which is a grief, but true ,at this point anyway.

But if it's a matter of introducing your hypothyroid body self to T3, then I think you have to

give it all the time in the world to adjust to accepting it. Watching your heart rate, ability to sleep and relax or not, levels of joint and nerve pains, feeling hot or cold, fuzzy-headedness etc. Try to remember how it was when you felt relatively all right metabolically and aim in that direction hour by hour, day by day. Not a theoretical amount from a text book.

The good thing is that with T3 you can feel the change of dose quite quickly.

See how you are after a day or two off, and then starting back on the lowest dose. If you are not feeling hyper, but fatigued , constipated etc, try upping by another quarter, as everyone else on the post has suggested. You will need to build up your strength gradually.

It's quite a balancing act , but i guess we are learning to tune in to our body's signals more than the average person ever has to-and maybe that is a positive thing?

Hello WildDeer

You have talked a lot of sense above, thank you.I hadnt thought about it in that way at all, about the hypo body trying to acclimatise to the T3. Yes, I will pay attention to the heart rate, sleep etc. and joint pains, constipation, yes they are all signs aren't they. I hadnt put them all together.

Do you take any T4 ? have you tried the NDT at all?

I am slowly cutting down my dose, and spacing it out a bit more. So far, I am starting to feel a little better. Trouble is, when I am feeling fatigued I can't tell if its because I have had too much, or too little T3.

What made you cut down from 50 to 25 ? Did you feel unwell or hyper ? My osteopath (retired GP) says if he was diagnosing me on symptoms and signs, (and dot the dreaded blood tests etc.) he would have said I was tending to hyper. SO hopefully the dose reduction will at least help.

I am terrible at night as my heart rate goes up and so does my pulse, which I have attributed to thyroid but perhaps isn't at all.

Thank you very very much for your help. Isnt this forum amazing ?

Hi Daffers,

It's nice to have been a bit helpful.

Sometimes it's hard to articulate what I think I understand about this whole thyro-razmatazz.

I was on T4 for 16 years , and it improved my energy, but left me with many symptoms which got worse through years of caring for elderly Mum, plus menopause, etc I wasn't told for the first 10 years that it was Hashimotos.

That helped me understand, via this website why my levels were increasingly fluctuating. GP was arrogant and dismissive, which finally galvanised me to go to dear Dr Peatfield.

It seems that because I have a conversion problem with T4 to T3, I'm unlikely to benefit from NDT because of the T4 in it.

I'm trying Ashwaghanda and Boswellia to help with processing the T3, and I feel that they are helping.

I cut down to 25mcg when it was very hot because the fibromyalgia became worse, acid-refux came on from taking painkillers, glands ached and head fuzzy from not enough deep sleep. It helped to do that, but I got more weary+ constipated.

The last 10 days I've edged back up to 40-ishmcg.

I have found everything that Dr Peatfield says in his book is helpful.

All the Best

I have just stopped my thyroid meds as I am so fed up with feeling as I do. 25 mcgs of Levo and 15mcgs of T3 sent my resting pulse soaring and I feel truly horrid for a few hours.

My latest blood results show my TSH to be 3.67 (range 0.35 - 4.5), but my Free T3 is 3.2 (range 4 - 6.8) and my Free T4 is 9.5 (range 11 - 24).

All other tests show good levels of Vit D, Ferritin, B12 etc.

My heart surgery for Aortic Valve replacement is in 5 weeks time and I am very concerned that all these symptoms of very low BP and fast pulse, low body temp, muscle aches and pains, headaches, etc are confusing as I can't tell which symptoms are caused by which issue. So, I ask myself the question - do I need medication at the moment. Why don't I wait until surgery is over. Process of elimination...!

I can only hope that once my valve is fixed my thyroid might get better. I can't feel any worse by not taking meds - can I?

Yes Susie - you may well feel worse by not taking thyroid meds if you need them!!! I'm sorry you've been so unwell and what a nightmare for you - but maybe you're taking too high a dose as the others have suggested here to Daffers. Do you split your T3 dose as others have advised? I can't add anything to Daffers as the replies here seem so sensible... Susie - if you haven't got some advice from your GP/endo regarding stopping your thyroid meds, please re-think... tho' I know GP/endo don't have all the answers either. Good luck to you and Daffers and hoping you both feel better soon!

Thanks Lisa. I am trying as you all say to reduce my dose slowly and spread it a bit more. I must say Levo was much easier than this.

Best wishes


Hi Andrea. I found levo easier too at first, but not quite effective enough longer term... and now I've got the balance with T4/T3 things are just as easy - the trick was finding the exact balance/timings. Good luck!

Hello Liza. Thank you for replying to my post. For the last 5 days I have felt so much better by not taking anything. Even my constipation seems to have resolved itself over the last couple days.

I saw my GP this morning and we have agreed to try the liquid form of Levo until I get my surgery done. But he strongly advises not to continue with T3 if I have such reactions with my high pulse rate and low BP. This might put more stress on my Aortic valve which has calcified and closed down too small to let good blood flow through.

Once my surgery is complete then maybe I can take stock of my general health and re-introduce T3 if need be. I have tried every way with Levo and T3. Different times, lower but more frequent doses. Not eating or drinking for an hour and always on an empty stomach in the morning.

And I've tried night time routines but the symptoms are the same. Today, I almost leapt out of bed, did my Pilates and felt really well. Bit breathless maybe (cardiac), but not aching or feeling like my heart was doing cartwheels. So strange to experience such an adverse effect.

It was comforting to chat with this GP today and be taken seriously. Sadly, he's not my regular GP.

Onwards and upwards.......! x

Hi Susie - I'm so pleased you followed this up and got some support and from someone who has listened. Thyroid issues are really wierd - I get insomnia when hypo - and this is supposed to be a hyper symptom. It's like a whole pack of wild cards where anything can happen. I wish you well for your operation - I will look out for your posts :)

Suzy, what is the liquid form of Levo called please ? Do you know where I can get it ?



There is information about most of the available thyroid hormone products, including liquids, on the main Thyroid UK site here:



Thanks Rod

Hello size

I am the person who put the post up asking for help with why I am struggling with T3 only. I was most interested to read of your troubles with Levo as I had exactly the same problems. For a short period between ending Levo and starting T3 (so not on anything) I too felt great. My heart has been really problematic on T3 only it races and utters altho ECG says all well.

My osteopath (retired GP very wise) thinks it's all down to the T3 and that I should wen myself off and see what happens . How did you do it and how long did it take ? I had 1/4 tablet 1 hour ago and my heart is racing - and that s after 2 months trying to get used to it. I only got up to 1 tab I total and so far today had 1/4 at 7 am and the other just an hour ago.

Would be grateful for any advice or comments

Best wishes


Good morning.

I decided to just stop my T3/T4 meds. I stopped once before and was persuaded not to go back on them. Every since I was diagnosed with Hypothyroidism (January 2014) and given Thyroxine my TSH levels gradually came down but my symptoms increased threefold. Therefore the Endo prescribed T3/T4 combo, as my FT4 and FT3 levels dropped well below the range. He thought I might not be utilising thyroxine properly but then my symptoms seemed to go wild with the introduction of T3. Initially, I was only on 5mcgs twice daily, eventually increasing to 15mcgs twice daily.

Two weeks ago I thought I was going to end up in A&E again. Unfortunately, due to my Bicuspid Aortic Valve and imminent surgery, many of my symptoms 'could' be cardiac related. It's difficult for me to separate the thyroid and heart issues. And why should they be separate as all body systems are interrelated (although the cardiac specialist says completely the opposite and says my heart has nothing to do with my thyroid)!

I know that within an hour or so of taking T3 my pulse would race, my anxiety and tremors would increase and on a few occasions if I was out walking, I would feel so worried about getting back home because my leg muscles would feel weak and unresponsive. As an endurance runner I have never experienced this sort of feeling even on my longest events, which have included two Full Ironman events and numerous marathons.

I know without a shadow of doubt that my medication is not suiting me at all. I don't have the answers and my current blood results came back yesterday with even lower FT3 of a month ago which is worrying but my energy levels over the last few days have been really good and I managed two walks of an hour duration for both walks with no symptoms described above. Of course I get out of breath walking up hill and I stop when necessary.

For the time being, I continue to be gluten and wheat free and eat no processed foods at all and take liquid vitamins - Vit D, B12 B6, Selenium and Vit C. I have no idea if any of these vitamins help but I seem to be able to tolerate them well.

I'm hoping my replacement valve will give me a much improved blood supply to all my body tissues including my thyroid. I can't continue with T3 no matter what the 'experts' say. Maybe I'm one of those people who fall outside of the 'range' and its normal for me as an individual to be low in FT3 and 4. In fact T3 is not recommended to people with cardiac issues.....!

I have to hope that my thyroid won't cause problems during surgery as I have read that in some cases it can cause hypothermia and the metabolising of medication for pain relief. I always have low body temperature and feel chilly even on warm days. It has to be really hot for me to feel warm.

I'm sorry not to be of more help and I know I have rattled on a bit. Best of luck to you whatever you decide to do with your medication.

Suzy x

You sound as if you are getting on amazingly well with it all. Sorry to hear about your valve problem its just so complicated all these cross-over symptoms, how can we ever get it unravelled.

I suspect I am like you and naturally want to fall below the range as you ssay.

Did you just stop 'cold turkey' ? I am so afraid of trying this as just cutting the T3 down a little causes me more palps and anxiety and shakes...I just dont know how to do it. I am on T3 only which doesnt help as when I was on T4 I was able to stop that, no problem (and felt much better).

Do you think if I was on both things for a while it would be easier to phase the T3 down or out ?



Sorry not to answer your earlier question. My liquid is just ''liquid Levothyroxine'' from Mercury Pharmaceuticals Ltd. It took my local pharmacy a while to track it down. I'm on a trail with it as its supposed to be so expensive - far more so than tablet form.

And yes, I did just stop both as I was feeling so lousy.

I have to decide if I want to go back to taking Levo even if its in liquid form. I still think its worth me waiting until my operation is over. My doc is very keen I take a small amount of Levo!

Hope this helps.

Sue x

Thanks for answering so quickly. I am seeing my endo Wed so will be armed with info. I would love to know hiw you get on with the liquid Levo



Good luck Andrea - Stay in touch - So will I :)

You may also like...