When do you take your second t3 dose? - Thyroid UK

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When do you take your second t3 dose?


It occurred to me that some people make a point of taking their second dose 12hrs after their first. Is that important? My dose is not split into two equal amounts so it isn't a matter of keeping my levels constant if that makes sense.

I am currently taking 50/75mcg levo and 15 t3 daily. I take the levo with 10 t3 around 7am or about two hours before I get up in the morning and then 5 t3 between 2 and 3pm. If I leave it later I get a terrible energy slump.

I've been on this dose around 6-8wks and generally feel pretty good. Not great, but I'm not getting the terrible exhaustion I had on a higher dose of levo or the memory problems I had on a higher dose of t3. I'm finally able to get out and do some exercise (swimming, walking). Planning a blood test soon.

18 Replies


You should take it at the time which suits you.

I used to take T3 only 3 x daily around 8 hours apart. On T4+T3 I used to take T3 on waking and at bedtime.

Cheers Clutter. It's so much easier to avoid the slump than to recover from it.


Absolutely :) I stopped experiencing the slumps in between doses a couple of months after I had good FT3 levels.

If I take it at 2-3 I don't get a slump, it's just if I leave it too long. I might try it all in the morning, see if that works better. Ideally I'd prefer one dose.

I take all my T3 (with T4) at night before bed, works for me. The half life of t3 seems to be disputed, some say 8 hours, some say 2.5 days. I find taking it at night provides a smoother effect overall.

Thanks. I may try this. Like you I felt better on one dose when I used to take 10mcg. I was adding the extra five to keep me going in the afternoon but I should give it a go all at once, it isn't like it's a huge increase.

I take T4 (75) & T3 (10) at 6am and T3 (10) at 10pm seems to work fine.

It's interesting you're taking half at bedtime. I feel like I need it to keep me going in the daytime and wonder about feeling overstimulated at night, but that isn't based on anything scientific, just the sense that taking it makes me feel alert.

I take it 5 mins before I go to bed, sleep the same as before. I was worried it would keep me awake but no it hasn't. Although I can get a bit weary late afternoon but because of taking it on an empty stomach I decided night time was best plus it stops me nibbling all evening knowing I have to take it later 😉

Take my T3 in one dose first thing in the morning (around 5:30am). Tried multiple doses throughout the day but feel better one one dose. Intrigued about taking some of the dose in the evening as I struggle with insomnia so wonder if that would help

Hi puncturedbicycle,

This is the similar daily regime for me too!

I take 15ml oral solution LT4 with 10mcg Lt3 at 06:30am and then 10mcg LT3 at 3:30pm (I do wonder even though I eat lite lunch at 1pm whether my stomach is actually empty at 3:30pm as my digestion is sluggish). I have tried experimenting with inverting all this with an evening main dose, but its really hard to fit in all my supplements...so at the moment I am sticking with the morning main dose!!

Just started to monitor my basal temperature through out the day at set times... getting up to 36.3oC ish on average. Used a mercury one which takes an age to get a true reading do gone for a digital one now.

I am introducing Metavive I [15mg] at the 3:30pm intake...

Naturally our T3 should be at its highest inthe early hours of the morning so taking it at bedtime is I think the most sensible time to take more and mimic what your body should. E doing. I did try that and I was beginning to sleep better. I've never been a night owl though so founds I was having to stay up later to fit it in after food. Give it a try and see if that works better for you.

I have gone back and forth on morning vs evening doses and like you I find a nighttime dose hard to work around food. I often like a small snack before bed (I eat an early dinner so sometimes six hours later I may feel a little peckish) or at least I'd like the option. For a while I took the levo at night and t3 in the morning. I find that if I take my t3 too early (eg very early or in the night) it sort of feels like it has 'worn off' by the time I start my day.

No doubt I'll continue to experiment for a while. I do have more good days now than I did before I started messing about with it so that's a good thing.

Glad it was giving you a good night's sleep, that is so important.

I take a 1/4 T3 before bed, about 10pm and a 1/2 in the morning with my T4, any time between 5 and 7am

It doesn't affect my sleep, that seems to have its own ups and downs (I wear a Fitbit and def feel more refreshed from a good night sleep)

I do have slumps during the day but that could be my Addison's

I'd like to try taking some of my T3 during the day but not sure when I'd fit it in with my other meds and food

I great question . I find that when I'm well dosed on T4 I don't get the T3 run out . I split my dose too .

Thanks for the reply.

The genesis of this leg of the thyroid journey is that I found my rt3 was slightly over range and was trying to find a way to reduce levo and raise t3 to see if it gives me more energy. I have struggled with fatigue for a long time and would do just about anything within reason to remedy that.

I tried very low levo and higher t3 and felt awful, so have raised the levo a bit from there and am experimenting with dose of t3. I may be technically underdosed (taking less in real terms than I was before) but I wonder if I'm using it better because less levo is being made into rt3 - ? I can't seem to raise t3 above 15 per day without feeling overdosed.

I was on about 100 levo and 10 t3 for the longest time and even at that low dose the t3 deffo relieves many symptoms levo alone can't get rid of, but the fatigue was pervasive. Right now 50/75 levo and 15 t3 seems better than before, for the time being anyway. I have more good days than I used to.

If you find and your labs confirm the same that you are well dosed on T4 I would say try 25g NDT . It gives you about 9mcg T4 plus 2.25 T3 . It might just mean that's all you need . But please split it .1/8 AM and 1/8 PM . To much of a good thing is not always good . You need and it's a must to let T4 build up in your system . It takes six weeks for that to happen . Let your body acclimate to any new changes especially with T4 .

Wishing you success as you proceed .

Many thanks. Not sure what you mean by 'well dosed on t4' - ? Trying to keep my levo low (to avoid rt3) so my test results should reflect that. Usually on a t3/t4 combo (incl ndt) t4 tests show levels on the low side.

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