Why T3, or Liothyronine, is Usually Taken in Multi-Doses Per Day

This blog post discusses why multi-dosing with T3-Only or T3-Mostly medication is more effective and safer for the majority of thyroid patients. It is not about dosing with mostly T4 medication and a little added T3. I am talking about full replacement daily dosages of T3, in the 40-100 mcg per day region. Smaller amounts of T3 than this are more easily managed in two doses or even one single dose per day.

I recently heard of someone who was advocating that thyroid patients should take all of their T3-Only medication in one single daily dose. They suggested that this ‘fills the cells and the thyroid receptors’ so that the T3 is then ‘delivered in waves over 24 hours’. Dr John C. Lowe was referred to as a possible source of this ‘information’.

I do not believe that this approach would work for most people.

Over the past fifteen years or so, I have worked with thousands of thyroid patients on the topic of how to use T3 effectively. Whilst a few of them can successfully take a single daily dose, the majority need to multi-dose in some way.

Here is how I came to this conclusion and how and why multi-dosing can work better for most people.

When I first started on T3-only, I tried taking my 50-mcg daily dose all at once in the morning. That left me extremely hypothyroid after about 8 hours. Over several weeks, I tried increasing the dose to make it last longer but I always became hypothyroid within 8-10 hours. It never lasted longer than this. By that stage, I was somewhat expert at assessing not only my symptoms but also my vital signs of heart rate, blood pressure and body temperature. So, I could see quite clearly that my metabolism slowed down after 8-10 hours – it was not my imagination. 

In this trial, I continued to increase the total daily dose of T3 from my normal 50 mcg until I eventually reached about 160 mcg of T3 per day. Two things became apparent:
1) I still became hypothyroid after around 10 hours.
2) I felt hyperthyroid during the early and middle hours. My BP became high, my heart rate was elevated, my temperature was slightly high and I felt anxious and ill.

The bottom line was that I could find no single daily dose of T3 that either lasted for 24 hours or avoided some element of feeling hyperthyroid at some points and hypothyroid for a lot of the time.

Dr John Lowe and I discussed this many times. He and I knew each other well. I read his book The Metabolic Treatment of Fibromyalgia about 6 times and he proofread and wrote the forward to my first book Recovering with T3. He supported the book and was going to heavily market it for me in the USA had he not died in an accident. We agreed on most things and we both saw that there were going to be different groups of people who would find one form of T3 dosing more effective than another.

John originally believed that, for a lot of people, taking T3 once a day was enough to provide a large genomic ‘kick’ to the cell nuclei. His view was that this would provide enough blood levels of T3, and intra-cellular levels, that there would be a T3 supply, albeit a lot lower than the initial ‘kick’, for long enough to just about get through 24 hours. He never believed that there was any mechanism to deliver T3 in waves over 24-hours. However, through our discussions, we both came to the conclusion that there might be different classes of people who have different needs.

The people that John treated were incredibly ill fibromyalgia patients. John himself had serious genetic resistance to T3 and this ran in his family (it had caused deeply serious issues for several relatives). However, most people who need T3 do not have such deeply problematic issues, myself included.

John and I basically reached an agreement that it was fine to have different modalities of T3 use available to suit everyone. I still believed that the majority of people would be more safely and more effectively served with 3 to 4 doses of T3 per day. There is no storage mechanism for T3 to be released in waves or bursts – this is not part of our physiological design.

I believed, and still do believe, that the best way to provide sufficient genomic bursts of T3 over 24 hours is to use multi-doses. This does not require stable blood levels of T3 in order to be highly effective. In fact, the free T3 level in the bloodstream can fluctuate significantly. What counts is whether the genomic activity in the cell nuclei is sustained at a healthy rate over 24 hours.

My work with thyroid patients makes me very confident in saying that 3 to 4 doses of T3 over the day suits the majority of patients very well and avoids both hypothyroid periods and any risk of hyperthyroid episodes. However, I have always believed that there are some people for whom 2 doses of T3 per day or even 1 dose per day would be sufficient. We are all different and no one solution works for everyone.

The protocol I developed for using T3 safely and effectively is described in detail in the Recovering with T3 book. The book shows thyroid patients and their doctors how to go about finding the most effective T3 dosage that is very safe for the individual. I also discuss the principles behind multi-dosing.

Here is an extract from Chapter 11 of Recovering with T3:

How T3 is usually taken each day – divided doses

Someone new to T3 replacement therapy may believe that the medication can be taken in a single daily dose, just like synthetic T4. This may work for a few people. However, for most people, the daily dosage of T3 will need to be split up and taken in smaller doses, known as divided doses.

This divided dose approach enables T3 to be taken at various intervals throughout the day, in order to provide a steady supply of T3 to the body. The use of divided doses also ensures that no single dose of T3 creates an exceptionally high peak level of T3 in the tissues of the body. Through the careful use of divided doses, it is possible to avoid the risk of tissue over- stimulation by T3 (T3 thyrotoxicosis). Some people refer to the taking of divided doses as multi- dosing.

In the UK, T3 is only available in 20-microgram tablets. Unfortunately, this makes matters rather difficult for the patient.

In order to achieve a divided dose strategy, the UK-based patient may have to carefully break the tablet in half (to create two 10-microgram doses), or into quarters (for a 5-microgram dose). If a 2.5 microgram T3 dose change is required, the tablet has to be broken up even further, which can be difficult.

In some countries, specialist companies, known as compounding pharmacies, can produce sustained release T3 for patients. This releases the T3 in a slow way. The idea behind it is to avoid potential issues caused by large peaks and troughs in the circulating level of T3 throughout the day. Sustained release T3 is sometimes referred to as ‘slow release T3’. However, there are mixed reports concerning sustained release T3. For those patients who require a full replacement of dosage of T3, sustained release T3 does not appear to work as well as pure T3. There may be many reasons for this. It is hard to tailor a sustained release T3 dose to provide enough T3 for many hours, without either providing too much, or too little T3, for some periods of time. This could explain why many of the patients who have tried to use sustained release T3 have chosen to go back to using pure T3.

When he initially prescribed T3, my doctor recommended that I split the daily dosage into two divided doses. I quickly discovered that two divided doses were not going to provide a steady enough level of T3 for me during the day. This is just one example of how limited the existing information on T3 was, as there were no recommendations to try smaller, more frequent doses, if the larger, less frequent doses caused side effects.

I have now communicated with many patients who use T3 replacement therapy. There are a small number of patients who do manage on two divided doses of T3 per day and a very small number, for whom one large dose of T3 appears to work perfectly well. However, the vast majority of patients using T3 replacement therapy appear to be using between three and four divided doses of T3 per day. I have also heard of some patients who use even higher numbers of divided doses but I would consider higher numbers of divided doses to be bordering on impractical.

I cannot emphasise how important it is for many people to employ T3 in divided doses. For a small proportion of people one or two divided doses of T3 apparently works very well. However, the careful use of three to four divided doses of T3 appears to suit many people extremely well.

Over the past fifteen years or so I must have worked with thousands of thyroid patients on the topic of how to use T3 effectively. This detailed experience has not changed my views. I still strongly believe that the majority of thyroid patients do better, have more effective results, and are far more protected from any over-stimulation and any hyperthyroid symptoms or signs, with multi-dosing of T3. There are always going to be exceptions to that and I wrote this in the above text in my original draft of Recovering with T3 – the text is still the same as it was back in 2011.

I, personally, have been taking 3 doses of T3 every day for over 25 years now. I have spare T3 tablets in the car and my pocket so that I can take them more or less on time, even if out of the house. It has become a simple routine, which is easy to remember. I used to put alarms on my watch/ phone but these are no longer needed because I remember to take my T3 more or less on time.

I also have a recent blog post that discusses how much T3 is typically required as a full replacement dose for those people on T3-Only. It also discusses how much T3 is equivalent to T4 medication (and how this is not a fixed mathematical ratio). I include this link because it is so relevant to this post. The two articles form a useful pair of blog posts. Together, they cover:
1) How much T3 is usually required to provide a full replacement T3 dose.
2) Why 3-4 multi-doses of T3 is often the best way for thyroid patients to take that full replacement dose of T3 (this blog post).

Here is the link to the blog post about T3 to T4 equivalency and how much T3 is often needed as a full replacement dose:

For completeness, I thought it was appropriate to also include a link to the blog post I have on Slow-Release T3 vs. Standard T3:

I hope you find this blog post helpful.

Best wishes,


Paul Robinson

Paul Robinson is a British author and thyroid patient advocate. The focus of his books and work is on helping patients recover from hypothyroidism. Paul has accumulated a wealth of knowledge on thyroid and adrenal dysfunction and their treatment. His three books cover all of this.

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  1. Kay on 14th November 2021 at 6:55 pm

    I would like to know if T3 medication is better versed a slow release T3 compound Could you give me your opinion or advice? Thank you.

  2. lee hebditch on 16th November 2021 at 11:51 am

    Hey, Paul

    Love the article. I have one question about multi-dosing T3 medication 3 or 4 times a day. I’ve heard that there should be a gap of four hours after eating before medication should be taken for maximum absorption, and one hour before food or drink. What is current medication timing each day to maximise absorption?

    Any advice would be gratefully appreciated, Paul.

    • Paul Robinson on 16th November 2021 at 5:33 pm

      T3 absorbs with or without food.
      Yes, with T4 meds or NDT you should take them on an empty stomach ideally.

      With T3 you just need to avoid some supplements like iron and calcium before taking it.

      But it absorbs fast and it works pretty easily.

      Best wishes, Paul

      • lee hebditch on 16th November 2021 at 7:58 pm

        Thanks, Paul.

  3. lee hebditch on 16th November 2021 at 8:21 pm

    Hey, Paul.

    Me again!

    I hope you don’t mind if i ask a couple of more questions.

    Firstly, i have read that the half-life of T3 medication is 5-7 days. However, i’ve also read that taking 25mcg T3 medication is fully metabolised within 8 hours and TSH returns to baseline. How can there be a TSH return to baseline if the half-life of the T3 medication is 5-7 days?

    And secondly, i’ve read that it takes 4-6 weeks to saturate the tissue/cells with T3 medication. Is this true, and if so, would you recommend new blood tests every 4-6 weeks while trying to gauge the correct dosage? Or is the saturation period different, if so, could you please tell me the duration so i can have new blood tests at the appropriate time.

    Many thanks, Paul.

    Keep up the good work…the GP’s need to know this information.

    • Paul Robinson on 17th November 2021 at 9:21 am

      Hi Lee,

      You should read the Recovering with T3 book. It explains all about T3. Half-life of T3 is about 24 hours but that is the blood half-life and it often does not tally with how long a dose of T3 appears to last which can be 3-8 hours depending on the dose size and the individual.

      TSH also often remains lower for longer than the 8 hours you refer to.

      You are getting your information from a dubious source. I would read the book as blood tests are also pretty useless when trying to assess the right T3 doses. The book covers it all.

      Best wishes, Paul

  4. Maureen Oxley on 5th March 2022 at 12:43 pm

    Hi Paul

    Can you tell me what heart rate would be acceptable 4-5 hours after taking 1 grain of NDT at 7 am?

    Second dose of 1 grain 3-4 pm.

    No later dose

    Many thanks

    • Paul Robinson on 5th March 2022 at 1:26 pm

      Hi Maureen,

      You never really want your heart rate very much higher than what is normal for you. It varies so much by person that I can’t give you a number.

      Plus heart rate is only one measure. Tracking symptoms and all useful signs (temperature, heart rate and BP) is important.
      What is most important when you aren’t sure about dosing is to track signs and symptoms prior to a dose, then every hour for several hours. This allows you to see any pattern of changes. It can help you to work out whether the dose was too high, too low and whether the timing was right relative to other doses. Checking it 4-5 hours after a dose doesn’t show the pattern – and the pattern is often the most informative thing.

      Best wishes, Paul

  5. Kit on 20th March 2022 at 7:47 pm

    Hi Paul,

    I have read your book, but I am a little confused about dosing on T4 T3 combination therapy. I have always taken my T4 in the evening. Do I need to add 3 doses of T3 now? I now it’s all individual but if I started with mcg at 6am, 5mcg at 2pm and 5mcg at 10pm, would that be a good starting point?

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