Taking T3 with food

In spite of having read to the contrary on this learned site, I just wanted to say that I note no diminished effect if I take my Cynomel just before, during or after eating. I am presently taking 50 Levo at 6 AM and 62.5 Cynomel (T3) divided into four doses. In the PIL instructions for French Cynomel there is no mention of when or how to take it. And I am feeling good on this dosage. And I take it with coffee sometimes too!

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23 Replies

  • L-T3 is very well absorbed. The larger L-T4 molecules are not so well absorbed.

  • My old doc (studied under Dr Weil, treated adrenals etc so not conventional) said it didn't matter and like you I've never noticed a difference in efficacy.

    I take my t3 in the morning w my levo because it's convenient but when I was splitting my dose I took it w or without food.

  • Tigreg,

    Taking throid meds with coffee can reduce absorption by up to 40%. T3 binds with the proteins in foods, as T4 does, and this is likely to reduce absorption. Perhaps you would take a lower dose if absorption was better.

  • Clutter , I thought you might say that! Actually, considering I have no thyroid and I'm quite a big fella (14 stone), I don't think my dose is so high. But thanks for your reply.

  • Tigreg,

    I didn't say it was high, I said it could be lower if absorption improved.

  • I initially took NDT with food & all the other things that I take that reduce absorption. It didn't work properly until I sorted my food & supplement routine out!

    My friend's hubby's T4 doesn't work effectively as he was told after his thyrodectomy, >30 years ago, to eat it with his breakfast of yoghurt, & coffee which he takes with an artificial sweetener. NOOooo...!

  • It's good that you don't appear to have any apparent effects by taking your Cynomel the way you do.

    I can assure you, after all of the problems I occured with levothyroxine, in no way would I jeopordise my T3 being affected in the slightest by food/coffee/tea or anything else. This is an excerpt by a scientist/logistician/doctor.

    Dr. Lowe: After most patients take T3, the level in the blood peaks after about two hours. T3 does directly affect the heart, and it’s likely that the high concentration of T3 that was reaching your heart briefly increased its rate of contraction. Clinical experience shows that few patients experience this after taking T3. It is of concern only in rare cases of patients with severely fragile cardiac status. Some patients, of course, find the increased heart rate annoying and prefer to avoid it. I don’t believe, however, that the proper solution is for the patient to take T3 with meals.

    By taking T3 with meals, a patient reduces the amount of T3 that will enter her blood. Some food constituents, such as calcium, bind thyroid hormone in the GI tract. This effectively limits the amount of T3 that absorbs into the blood, the rise of the blood T3 level, and the brief exposure of the heart to higher concentrations of T3. But there is a problem with this approach.

    The patient who takes T3 (or T4) with meals won’t have anywhere near an accurate idea of how much T3 enters her blood. Different meals will contain different amounts of T3-binding substances that will reduce the amount of T3 that enters the blood. One meal may contain a small amount of T3-binding substances; another may contain a large amount. As a result, the amount of T3 that enters the blood after meals is likely to vary a lot. Accordingly, the degree to which T3 drives the patient’s metabolism any day is also likely to vary widely.

    Taking T3 with meals, then, blurs the relationship a patient and her doctor may look for between her dose of T3 and her metabolic status. The proper solution is simply to reduce the amount of T3 the patient takes on an empty stomach. With this approach, the relationship between a particular dose of T3 and metabolic status will be far clearer.


  • shaws thanks for that. It would seem to make sense assuming that it is true that certain food constituents bind with thyroid hormone....all I can say is that I have never been aware of more or less T3 hitting my metabolism at any point. And there is no particular attention drawn as to how to take the medication in the patient instruction list. You would have thought they would specify to take it between meals if it were that important.

  • I think many Endocrinologists have no idea about how liothyronine works and that assumptions are made as I frequently read about splitting doses of T3 or it is unstable etc so that may prove difficult for some to find a suitable window. If you are happy and well, then whatever you are doing is fine.

  • Trouble with the phrase "with food" is that it covers so many possibilities!

    There seems to have been little research on the impact of food on T3. We always have the same fundamental issue, though, and that is that some foods might have little or no impact whereas others have a major impact.

    Let's just think about the possibilities for breakfast:

    Croissant, toast, other bread--based foods.

    Cereals including rice, corn (maize), oat, wheat, etc. - some of which might be fortified with iron and other substances.

    "English breakfast" with bacon, sausage (and who knows what goes into them!), eggs, black pudding.

    "Continental" with lots of cheese and ham.

    "Healthy" with yogurt, fruits, etc.

    It could be that just one of these, only soft boiled eggs?, only cereals?, only black pudding?, actually affect absorption. But if we don't know which, and treat all food as OK, we could find ourselves suddenly under-dosed on some days - only on holiday?, only when staying at a decent hotel? only when someone under-cooks the eggs?

    In order to avoid this lottery, the only approach I can think to apply is not taking close to any food. I guess experimentation could allow someone to see if particlar foods have noticeable effects, but it would be all too easy to miss precisely what differences between foods are important and so make mistakes.

  • helvella , thank you for that. But why don't they state something to that effect in the PIL?

  • The number of things NOT stated in the PILs (and equivalents, so far as I have read) is astonishing.

    I could start with a brief extract from the current Actavis 100 microgram tablet PIL:

    3 How to take

    You may be taking this medicine for the rest of your life. Always take Levothyroxine tablets exactly as your doctor has told you. If you are not sure, check with your doctor or pharmacist. Your dose will be decided by your doctor and will depend on the results of your blood tests. The dose you should take will be on the label attached by your pharmacist. Swallow the tablets with plenty of water. You should usually take your tablets before breakfast or your first meal of the day.


    No mention of any gap between tablet and food at all. Despite considerable evidence of an impact.

    PILs are often many years out of date - lagging far behind accepted research. We see that something mentioned in the PIL for one make is not in the PIL for another make. As above, an implication that bed-time is not even an option, let alone possibly preferable for some people.

    It is difficult to see what incentive there is for pharmaceutical companies, especially the generic companies (indeed, any company once the product is multiply sourced), to put any effort into the PILs beyond what they have to.

  • I did experiment with magnesium supplements, and found I need to leave six hours between my T3 and my magnesium. Presumably, that would also apply to anything that contains magnesium, like milk of magnesia, etc.

  • greygoose , Strange, I'm taking my magnesium supplement at about 10.30 / 11.00 PM just before bed and after my last T3 dose which is at 9 PM. Feel no difference. Just goes to show we are all different - or maybe I am the exception. My partner would agree with that! Ha Ha !

  • Hi greygoose,

    I was on T4/T3 for 15 years (until they decided to experiment by taking away the T3!) and would take magnesium with breakfast about an hour afterwards,which never gave me any problem at that time.

    Now that my body is completely confused by swapping the medication,I have tried to take the magnesium at different times,but it doesn't seem to make any difference to how I feel apart from affecting my stomach.

  • What sort of problem would you expect it to give you? I'm not talking about having problems as such, it's just that I knew my T3 was better absorbed when I left a gap of 6 hours.

  • Hi greygoose, I thought maybe if it wasn't being absorbed properly,then I would be more tired,like it wasn't working.Mind you I am totally tired all the time at the moment after keeping swapping medication!

  • So, during 15 years, whilst you were taking T4/T3, and taking your magnesium one hour after, you had absolutely no symptoms? You were perfectly fit and healthy?

  • Hi greygoose,

    well we all have problems from time to time, but nothing I could put down to magnesium conflicting.I have suffered badly with migraines over the years,but these improved when I went on HRT and more so when I gave up work.I have tried not having magnesium,but definitely feel better taking it.How did you work out that it was better absorbed when leaving a 6 hour gap?

  • That's the problem, isn't it. We don't realise that some things are due to low hormones - I certainly wouldn't suggest you gave up your magnesium! Just leave a longer gap. Why do you have to take it at breakfast? Most people take it in the evening.

    There are over 300 known symptoms of low thyroid. A lot we would put down to just growing older (but that's what growing older is, isn't it, the slowing down of hormone production).

    I had read somewhere, when looking for something else, that magnesium should be taken six hours away from thyroid hormone. But, I didn't book-mark it, and when I went to look for it again, I couldn't find it. I had been taking my magnesium in the morning, and T3 at night, so I just tried taking magnesium at night, too - just two hours away from my T3. My skin turned to scales. Always a first sign of under-medication with me. So, just left a longer and longer gap until my skin improved again.

  • Hi greygoose, thanks for that.

    I have tried taking magnesium at dinnertime, in the evening, but my stomach doesn't seem to like it!

    I'm only on 150 as when I tried a bigger dose again my stomach rebelled!

    To be honest at the moment with keep changing my medication, I don't know where I am as every time the dose is changed it takes a couple of months to settle down,then I find it isn't working and have to change it again.

  • Sounds as if your doctor is just dosing by the TSH. I think you should post your own question, With your results, and ranges, to find out what's going on. It's not normal to have to change doses all the time like that.

  • I always think consistency is impostant so as others h e said if you have always done this and feel fine that your medication is 'right' for your present life style. However I would be worried about the days you over dose on coffee, skip a meal etc. that I'd bound to cause some sort of hiccup and although notvfelt then it could be further down the line. For that reason I try to do what is suggested as sometimes other things could be out of my control

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