If you take a small dose of T3 (6mcg) does this... - Thyroid UK

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If you take a small dose of T3 (6mcg) does this slowly build up in your system or will it get used quickly every day?

ockerdoc profile image
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I’m taking 6.25mcg of T3 for a week now I just wondered if this will build up in your system similar to T4? I know T4 is the storage hormone so that builds up slowly. I didn’t know whether the 6mcg will build up aswell as I was thinking of adding a little more but I don’t want to add more if it’s still building up in my system if that makes sense. My resting heart rate is still in the low 50s so I don’t think I’m still properly medicated. Thank you. 🙏

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Regenallotment profile image
RegenallotmentAmbassador

my understanding is T3 is used up within 24 hours, in my experience I had some Roseway compounded T3 that seemed to let 48 hours, I’m on Thybon Henning now and I’m pretty sure I rip through that in about 8 hours.

What I have learned from trying all sorts to find my perfect doses is that my vitamins and ferritin have to be top of ranges, definitely top 25%, my T4 needs to be at least 70% through range before I benefit from T3. If any of these are low, I remain symptomatic and the T3 makes me jittery and hungry and I get even more aches than normal.

Not sure if that helps, when did you last do a blood test on full thyroid and vitamins?

🌱

ockerdoc profile image
ockerdoc in reply toRegenallotment

Thank you I last tested around 5 weeks ago my T4 was only 25% through range so I moved from 115mcg to 135mcg T4. Haven’t been feeling too bad actually but I’m eating relatively lowish carb now..around 75g a day net carbs so that’s why I’m adding the T3. I could add another 3 to the 6mcg T3 and see how I feel maybe. I’ve been feeling less energetic the last week. My vitamins are all good all in top quadrant of the ranges.

FallingInReverse profile image
FallingInReverse

My two cents:

Fast acting vs half life- I find it helpful to remember that just because t3 is fast acting (hours!) is different from how long it stays in your body, ie an 18 hours to 2.5 days half life depending on who you ask.

Consistent blood levels: even if it doesn't accumulate, steady regular dosing creates a steady level in the blood. Which is important when you look at the feedback loop.

Feedback loop- so whereas the T3 may not build up like T4 does…. Don’t forget the role it plays in the hypothalamus-pituitary-T4-T3 feedback loop. Different levels of T3 in the blood will impact other thyroid-related functions.

Building up a titration… that being said, personally I often titrate slowly. For example, I will intend to titrate Levo by 25 mcgs. But will take a couple weeks or more at 12.5. So after a couple weeks I might add more (like where you are at) BUT the trick for me is that I won’t test until I have been on one stable unchanging dose for a full 6 weeks.

I’m guessing you feel zero different with the 6.25?

If it was me, I’d wait another week on the 6.25, then increase, staying on that for 6 weeks then test again.

That’s just what I’d do.

edited “short acting” to “fast acting”

greygoose profile image
greygoose in reply toFallingInReverse

I find it helpful to remember that just because t3 is short acting (hours!) is different from how long it stays in your body, ie an 18 hours to 2.5 days half life depending on who you ask.

Mmmmmmmmeu... I wouldn't call it short-acting, no.

According to diogenes, the half-life of T3 - i.e. the time it stays in the blood - is about 24 hours. However the T3 that gets into the blood stays there for about three days.

T3 does not get 'used up'. Certainly not in a matter of hours. When it's in the blood it doesn't do anything, you have to get enough into the cells to feel anything. Those that feel it gets 'used up' are probably not getting enough into their cells.

And, whilst it doesn't build up in the way T4 does, if you take the same amount regularly, every day, it does build up a tiny, weeny bit. Remember, half-life does not mean it's all out of the blood in 24 hours, it means that there is half as much as there was - less what gets into the cells.

FallingInReverse profile image
FallingInReverse in reply togreygoose

By short acting I am referring to the post-dose peak for t3, esp in comparison to levo.

Links like this, which I’m reminded is the one I used to design my own split dose strategy to effectively align my t3 dose to lift me from my afternoon nap: thyroidpatients.ca/2020/07/...

One of the T3 pharmaceutical’s strongest assets (which some doctors think is a weakness!) is its fast-acting nature, which goes hand in hand with its short half-life.

T3 post dose
greygoose profile image
greygoose in reply toFallingInReverse

You said 'short acting', not fast acting. Not necessarily the same thing.

FallingInReverse profile image
FallingInReverse in reply togreygoose

Edited! I missed that and blame it on the brain fog : )

ockerdoc profile image
ockerdoc in reply toFallingInReverse

Great thank you yes that’s what I was going to do. I’m definitely trying to get my diet and thyroid levels consistent for 6 weeks so I can see where I am and where I need to be.

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