Thyroid UK
84,318 members99,326 posts

T3 dose timing

So, it's me again, sitting here, trying to fight off all the nasty hypo symptoms while on synthetic T4/T3 combo... and wondering which method to use: the CT3M or taking a single T3 dose at bedtime.

For the last 4 days I've been taking T3 and T4 1-4 hours before my usual waking hour (trying to mimic the CM).

In the last 2 months I've started experiencing some sleep disturbances. I wake 1-2 times a night, which is a relatively new occurrence. I guess it has to do with my hypothyroidism, low FT3, I may even have low cortisol as a consequence.

Currently I take 37.5 T4 and 12.5 T3 as soon as I wake up prior to my official waking hour and then take another 12.5 T3 about 6 pm.

I haven't felt even the slightest improvement yet.

The CM, if I'm doing it right at all, does not seem to work for me.

How about single dosing (25mcg T3) at bedtime and then raise the amount of T3 taken during the day by adding another 12.5 dose in the morning or at lunch?

Besides, I can't figure it out whether I have to take T3 only as my CM dose or T4+T3.

25 Replies

I have always taken any thyroid hormones once daily, i.e. T4 - T4/T3 - NDT and T3 only. I am fit, well and symptom-free.

Its much easier and considering we have to take them for a lifetime I want an easy, healthy (more or less normal life) :)


So, do I believe that "cycling" will "cure" cellular resistance to thyroid hormone? Unequivocally, no!

Third, the leaflet on Cytomel pharmacies give patients when they fill their prescriptions states, "POSSIBLE SIDE EFFECTS: NO COMMON SIDE EFFECTS HAVE BEEN REPORTED with proper use of this medication." This information is accurate—when plain, full-strength, one-time-per-day doses of T3 are used properly, there are no adverse effects. The only adverse effects occur when a patient takes a dosage that for her is excessive. With Cytomel, if overstimulation occurs, it can be stopped with one or two small doses of propranolol. Or the patient can simply reduce her dosage of Cytomel the next time she takes it. I want to emphasize, however, that when our protocol is used properly, there is no overstimulation to be avoided by using timed-release T3. The protocol has safeguards against adverse effects.

And finally, why do I specify that the typical patient use one full dose of non-timed-release Cytomel for life? Because extensive testing has shown that this is safe, effective, and most economical—when used within the context of our entire protocol.


Than you again, shaws!

My hypo symptoms even got worse trying to use the CM. How is that possible?


This method doesn't suit all.

I go by Dr Lowe (deceased) who used T3 himself plus his thyroid hormone resistant patients. He has stated that the work of T3 is to enter our cells with a dose which suits us. Once the cells are saturated with T3, its work then begins and the effect of that one dose lasts for between one to three days. He was a scientist/researcher/doctor and specialised in metabolism.


I see.

Shaws, you told me the other day that your hypo symptoms (skipped beats being one of them) went completely away when on T3 only. T4/T3 therapy didn't suit you.

Was it the case you had a very high rT3 and a great part of the T4 medicine was being converted to too much rT3?

Have you had your rT3 tested?

Or was it some other cause?

I seem to be getting more and more hypo while on T4/T3 therapy.

I'm going to stop T4.

Endo told me to stop T3 and continue on T4 alone as I am hyper. lol

Heart rate is in the high 50s - low 60s, the skipped beats won't stop and are even getting more severe, I am not hyper at all...

1 like

Endos and doctors have been told to only prescribe levothyroxine as they have taken the pharmaceutical companies words that it is a perfect replacement for a failing gland.

They forget they are dealing with the human body and we are all so different. Some of us have allergies - others cannot take certain medications but hormones shouldn't have a bad effect but maybe if levo cannot be converted efficiently by some bodies, or doctors stop increasing when TSH reaches within the range of TSH instead of 1 or lower and the patient has clinical symptoms so patient might have insufficient T3 which is the engine.

New Research has shown that some patients need T3 as well as T4.

Your heart rate doesn't show you are hyper - your Endo has probably only looked at your TSH and decided if it's below 1 you are hyper never mind he hasn't taken account of your hypo symptoms.

Re RT3 I'll give you another link, both are by a Scientist/Researcher and doctor who published many articles and is against this modern way of treating patients. Dr Lowe was also an adviser to before his early demise.

Go to the date March 24, 1999 to read about RT3.


That made me look at rT3 from a different angle.

I assume it is the T4 in my synthetic T4/T3 combination therapy that is making me more and more hypo, that's why I dropped the T4.

If I have thyroid hormone resistance of some sort, with T4 worsening my hypo symptoms, is it possible to never get better even on T3-only therapy? Have you heard of similar cases reported?

I think T3 only therapy is the last thing I can try.


I am well on T3 only but there is also Natural Dessicated Thyroid Hormones too, made from pigs or cows thyroid glands. These were the original thyroid hormone replacements in use since 1892. Before that we just died.

Dessicated Thyroid hormones contain all of the hormones our gland would produce If healthy. T4. T3, T2, T1 and calcitonin. Unfortunately most of the modern Endocrinology Associations don't advise this even though it has had a long and successful story in the past. Big Pharma has been good at 'persuading' the Associations to only prescribe levo (they make more money of course)

Also even levothyroxine might work if we are able to try different makes as sometimes it is the fillers/binders in any of the products which might contain something that doesn't agree with us.

It Is trial and error but there can be a light at the end of the tunnel.


CT3M didn't help me from a symptom perspective. I too take my t3 all in one go first thing in the morning w my levo. If I take it too early it feels like I've missed the best of it (like it has sort of worn off) so I take it maybe an hour or two before waking. Hope that helps.


Hi Yuliana

I'm glad I'm not the only one thinking about timing! It's diving me nuts! I get a little obsessed with timings for T3 and timing between taking my vitamins! I'm currently taking 100mcg of Levothyroxine and 6.25mcg of T3 at about 5.30 (upon waking) and I've just started taking another 6.25mcg of T3 at night (normally about 9pm upon getting into bed) I'm struggling a little as I go to the gym after work and I have to stop eating and drinking (only water) at 7pm.... plus no cuppa tea from 5pm :( due to the milk. I'm going for a meal at 8pm and Im stressing about when to take my T3 as I don't want to wait up for 2 hours after I've eaten.. some people on here take their full T3 and T4 dose together in one go... I'm thinking that's what I might try and do. Seems so much easier :)

Let me know who you get on?


Let me know how you get on? Not who ;)

1 like

Shaws, Lindsayf, I am currently taking 50 mcg T3 in 3 doses and there is absolutely no improvement. I keep enduring tens of thousands of skipped beats every day along with other symptoms. Skipped beats are my major hypo symptom. Although rare with hypo, it has been my most prominent one. Taking 50 mcg T3 is just like taking an aspirin. I don't feel anything at all, no shakes, nothing... no improvement.

I cannot help thinking there is something terribly wrong with my case. Either I am totally hormone resistant (even to T3), which I believe is the least likely explanation, or my Greek Unipharma T3 (or this batch in particular) is not much potent.

Or I am just clutching at straws...


Ellismartin, I did stop my T4 5 days ago and have been on T3 only since then. Even raising my dose :(


Ellismartin, can one become resistant after only a year on T4?

I suspected I may be resistant when I was severely hypo on 75 mcg T4 (thousands of skipped beats), stopped T4 for 5-6 days, then resumed taking a much lower dose, 37.5 mcg, and the skipped beats vanished on the second day of this restart. I managed to get on 37.5 T4 for 6 months and then the skipped beats slowly have returned.

That is why I stopped taking T4 now.


I would like to receive some advice on my latest results from this morning, 2 hours after taking 25 mcg T3. I got some rather strange and disturbing results: TSH:0.014, FT4 is a little over mid-range, FT3 is 21 (3.10-7.10).

If this was true, I should have been intoxicated and severely hyper, which I am NOT. My heart rate is in the low 60s, I am having skipped beats (my major hypo symptom), I have absolutely no change of symptoms whatsoever.

Any insight, please?



T3 peaks in the bloodstream for up to six hours after taking a dose so that is why FT3 is so high. One of the reasons doctors are so anti T3 is because of the temporary peak levels of FT3 after taking a dose. Splitting 25mcg into 2 or 3 doses will even out the peaks and troughs.

TSH 0.014 is very suppressed and this will be nothing to do with taking T3 before your blood test. FT4 mid-range suggests you are taking T4 in addition to T3.

Next time you have a blood test take T3 after the blood draw.


Clutter, I stopped taking T4 6 days ago, but my FT4 must have been high.

I know T3 peaks in the bloodstream but I did not expect mine to be so much over range judging by my hypo symptoms.

Don't know what to do:

1. to lower the T3 dose since my FT3 is 3 times over range or

2. to continue taking the same T3 dose till relieve of symptoms?



How much T4 were you taking before you switched to 25mcg T3?

I've seen several members with FT3 3 x over range when they've taken T3 or NDT a couple of hours before their thyroid test. I wouldn't change dose on the basis of that result. I would retest in 6-8 weeks and make sure you take T3 after the blood draw.


Clutter, I was taking 37.5 T4 and 25 T3 but I was getting more and more and more hypo as each day passed. That's why I decided to stop T4 6 or even 7 days ago acting on the presumption that I might have a high rT3 problem.

My reverse T3 result will be ready in 10 days, so I will know my rT3 level as well.

Since stopping T4 I was gradually upping my T3 dose since I tolerate T3 very well (it gives me absolutely no hyper symptoms) and now I take 25 mcg in the morning (about an hour before waking), 12.5 mcg in the afternoon and 12.5 mcg in the evening. There is no change of my hypo symptoms that is why I was totally astounded by this morning's result.

It is a consolation to know that 3 times over range T3 result is not that uncommon among people taking T3.



"It is a consolation to know that 3 times over range T3 result is not that uncommon among people taking T3" - only because they took T3 or NDT prior to their blood draw. If you leave 12 hours between last dose and blood draw FT3 should remain within range.

It took 10 weeks off T4 and 2 weeks off T3 (no meds at all) to clear the build up of T4 I thought was making me unwell (I didn't test rT3). I felt unwell a day after resuming T4 only but adding T3 calmed the adverse effects I was having and I've been fine on T4+T3 since.

It's not uncommon to need 3-4 months on T3 only to clear high rT3 before symptoms improve. It can clear instantly and you may need to reduce T3 dose by up to two thirds to avoid feeling over medicated.


Thank you, Clutter!

I really hope I have a high rT3 problem. Otherwise my strong lingering hypo symptoms will be unexplainable. Apparently T3 cannot reach my cells.

I have also come across the following information:

Thyroid hormone levels, in excess, will affect other lab results. Total cholesterol may become quite low, while SHBG (sex hormone binding globulin), calcium, and alkaline phosphatase may become elevated. The last three markers correlate with hyperthyroidism and bone loss, and should not be ignored. [2] The hyperthyroid state (too much T3, not a low TSH) causes osteoporosis, which is why doctors are so wary of prescribing too much T3. [3] Cortisol, free testosterone and DHEA values may also fall below the reference range when too much thyroid hormone is taken. [4] This may explain why so many are told to take hydrocortisone and supplement sex hormones when on the T3-only protocol.

I think it might be true only if one is really hyperthyroid at a cellular level.



It is worth checking your ferritin, vitamin D, B12 and folate are optimal as deficiencies and low levels can cause symptoms similar to hypothyroid symptoms.

Before assuming you are hypothyroid at a cellular level give T3 a few weeks to work and make sure the vitamins and minerals above are optimal.


Clutter, I am 100% positive I am hypothyroid at a cellular level. I know my symptoms so well, have been having them on and off for the last 3 years.

I don't even have to take my temperature and BP, I can only go by my skipped beats being my main hypo symptom. I experience them on a daily basis when hypo and now I have been having them for the last 4 months every day. I also have other symptoms that cannot go unnoticed.

My ferritin is low but my iron is high, over mid-range, so I cannot take iron supplements. I am supplementing B12, D, and folate.

Can a high rT3 be the result of T4 therapy solely?



Yes, high rT3 is almost always caused by unconverted T4 which is why T3 only for 3-4 months is helpful in reducing rT3.


Thank you, Clutter!


Clutter, Shaws, my fatigue, afternoon crash and bone and muscle pain went almost completely away on 50 mcg T3 and no T4. (I stopped T4 about 13 days ago.)

There is also a great reduction of my daily skipped beats, up to 80%, I would say.

However they don't seem to be going completely away anytime soon.

Shaws, how far into your T3 treatment did the skipped beats disappear? How much T3 do you take?

I had about 15000 + skipped beats daily (yes, 15000, that's correct) out of which I was feeling about 10000.

Now, I feel about 150-200 daily, which is a huge relief, as you can imagine.

4 months ago, after the birth of my second child, I was feeling zero skipped beats per day. I know it's not my heart, it's my thyroid. I know I'm am still hypo, but I am on a fairly large dose of T3 (25 mcg - in the morning, 25 mcg - in the afternoon).

I am afraid I might have some sort of thyroid hormone resistance but I am not very willing to increase my dose, out of fear.

Don't know what to do. Any advice?

Thank you!


You may also like...