Thyroid UK
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Any runners with Hashimotos on T3 only ?

I am slowly but surely running again. I have pretty consistent this month after taking off about 2 years. I am using T3 only, and I recently found out that running causes your T3 storage to deplete. Which explains, the slow recoveries.

I would like to know who takes T3 before or after their run ? If so how much T3 do you take ? And how did you figure out this amount ?

I did take 1/2 pill of 12.5mg before my run today...but so far I noticed a little effect.

Then again, I take alot or 1/2 pill is not likely to have any effect on me. 😰

Any wisdom, research or help is most appreciated !!!

28 Replies

T3 doesn't work so quickly. It has to be absorbed into the receptor cells before it's work begins. The link is just for information re T3.


Shaws-Thank you. However, there is no link ?


Thanks Shaws, but it has been removed.:(


It opens up for me when I clicked!


Oh it opened up. Thank you!!!!


Shaws-Please explain your thoughts on this article. Basically, Dr. Lowe states that the effects of T3 on the body continue up to 3 days following ingestion. So T3 is not short lived only up to 8 hrs. This makes sense to me.

Are you saying that taking T3 before exercising will still help? Or that if T3 is taken immediately before exercise there is not enough time for the T3 to get into the receptors, cells, etc.?

For example, I take my T3 only all at once at 3h30 AM. It lasts me pretty much through the evening, but I do notice it wearing off a bit.

My example. Yesterday I ran for 50 min on the treadmill. It was challenging, but alright. After I finished I felt fine. However, as the thought of taking T3 before or after is new to me-I forgot completely.

Late evening, I felt very tired and ankles started to swell. Thus AM, even though I took my T3 at 3h30 AM. When I awoke at 8 AM-I felt like I was hit by a truck!! But I noticed ankle swelling definitely decreased. Then, I weighed myself. I have gained with all tge running! The more I run, the more I gain vs losing weight.

Evidently, even though I feel better with running-its depleting my T3. Definitely bitter-sweet!!!

Agh! There must be a solution for this! I know now any amount of T3 should help.😖😭

Definitely, I won't forget the T3 next time, and I will closely monitor my calories as well.


I am not medically qualified but assume that once you're on an optimum dose your energy will not reduce to such an extent. We have to listen to our body and if you are so fatigued take it easier and slowly - every two weeks say, increase slightly.

I am now able to decorate/paint my home now: do gardening and husband tells me to not do so much but energy remains although I feel a bit tired by evening.

But when I awake next morning I definitely know dose is due as my heart picks up pace but when take dose it calms down to normal.

It's more important to get to a stable dose and come to realise that we are using 'synthetic T3' even though it is a lifeline to us and be kinder to our bodies that have gone through traumas of thyroid deprivation maybe for a long time before diagnosis.

I was once bedridden due to no diagnosis of hypo.



Shaws-I understand. I need to take it slowly.

Everytime, I get closer to figuring my body out, yet another puzzle to be solved.

Thank you..though for reminding me this is a process.


It is a process and not always a quick one :)


When I was running I used to time it so I took a dose of t3 just before a run and it seemed to help power my muscles.

May I ask what your regimen is (how far do you run, sprinting, jogging etc)?

Don't be surprised if someone tells you off for running and depleting your t3! Some people think that Hashi's and exercise don't mix.


Puncturedbicycle- Thank you. I know running tends to be looked at as counterproductive with Hashimotos. Except running is what makes me feel healthy it helps me to disconnect, di-stress, feel free and the serrotine helps my mood. I also hope it will help me lose the weight I have gained in the last 2 years.

I am running 1 hour a day. However, 2 years ago I ran a marathon. At the time, I didn't know I had mercury poisioning and I was poorly treated for my Hashimotos. As a result, I lost 2 years trying to heal my body.

Only now,mercury free and via self-medication with T3 I feel almost normal again with the craving for running.

I am running approximately 8ish kilometers or for 1 hour at a 7.40ish minute per kilometer. Right now, I am just taking it easy to get back into it and trying to get fit again.

Any suggestions, as Shaws said- maybe taking T3 right before the run is pointless as not enough time to get into the receptors??


Yes well we're all individuals and if you crave an activity that makes you feel well (and research shows is good for you) then I think it's great! There aren't a lot of easy answers in life, so if you find one you should feel free to enjoy it.

I should have mentioned I take both t3 and t4 and I used to split my dose of t3 to twice a day when I was running.

I think it is a matter of experimenting to see what suits. I don't run anymore and I can't remember how I used to time the t3 (don't know if I took it just before or an hour before or what). But for whatever reason it definitely seemed to help. My runs were shorter than yours and I wasn't looking at anything like the same distances. I did stints of 3 miles at a time twice a day, and I was happy to be a plodder so I wasn't looking at improving times or anything.

A lot of people suffer after marathons, even those at peak physical fitness, so it could have been anything that laid you low.


I appreciate your kind reply. I have been thinking about Shaws' comment. Maybe it might be better if I take the T3 after ? This way my body can absorb the T3 when there is a deficit and I have finished my run to absorb away.


I think anything is worth experimenting with. But be sure to keep a diary so you learn from it.


Definitely, will do ! Thanks for the support !

1 like



I do triathlon. Since developing hypothyroidism I find after cycling or running I get very very cold and it takes much longer to recover than before.

I'm trying T3 after exercise but so far not seeing much difference. My doctor doesn't think it's due to T3 but cannot offer any alternate reason for it.


PattyOdores-Wow, thanks for the reply. I can tell you before I switched to T3, I always remember getting very cold and being wiped out afterwards. I can tell you know however, personally after being on T3 only and beginning to run again. It is now MUCH, MUCH better since being on T3. I am also not cold all the time. In fact, the opposite my husband reminds me. I now open the window at night in late October !

Yes, I would say the hardest part is trying to figure out per X time exercising how much X of T3 to compensate ? And is it better before or after exercise ? I am thinking afterwards. Can you tell me how much you have tried taking after exercise without success vs. how much you take normally? I believe strongly its all about T3 makes perfect sense now for me.


I currently take 100 T4 daily and no T3. After exercise I have started to take 12.5 T3 but no difference felt yet.

The coldness and wiped out bit comes about an hour after I've finished.

I don't want to give up exercise, it keeps me sane!!

I think I will keep a diary and start upping the T3 and see how it goes. I considered trying to get a blood test at the time I get the cold/wipeout but unsure if bloods will show it at that time or not and don't want to waste money.

It's so difficult isn't it.


OK sounds good. Please let me know how it goes. I will do the same. A question though, how are your thyroid levels ? Specifically, your RT3 and T3 ? I am curious why your Dr has you all on T4 but then T3 after exercise ?


My T3 is at lower (about a third) end of scale whenever tested. No idea re RT3 but that will be my next test, full panel. Have to get it privately of course.

My doctor doesn't know about me taking T3, I'm self medicating just after exercise. I tried taking a small amount daily but that made me feel more hypo and I'm suspicious re my RT3.

My T4 at 100 daily seems to keep me towards very top of scale. I feel absolutely fine, apart from after exercise.


I would definitely check your RT3 and also your antibodies, and full panel of B12, Vit D, Iron serum, *Ferritine, Sodium, Magnesium, Potassium, Selenium. Basically, A-Z all that they can...if you can.

Do you have Hashimotos ? Do you take any supplements ?


I too must continue the it keeps my sanity and I forget all about the Hashimotos on my back. 2 years of little exercise or just walking really did not help and only made me dread more about everything, etcetera. I tried the taken it easy approach for my immune system along with a very healthy, no gluten, little dairy, no grain diet...and all of it still did not give me the sanity. I guess we all have to take care of ourselves, but definitely find our own personal happy place.


Ditto. Taking it easy just wound me up and gluten free made no difference (I tested positive to hashi's). Giving up exercise would more than likely see me on anti depressants.


Sorry missed that. Any idea what ur Hashimotos antibodies number was ?


It wasn't very high, but was out of range.

I do supplement, b12, d3, selenium.

Going to get a full panel done next week I think. Been cyclo-crossing today and now sat shivering!!

Good luck with your T3 and exercise, keep in touch and we can swap notes 😀




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