T3

[lukk3395]

Hello all,

Any of you have tried taking T3 only? any benefits or fucked up sides?
im 4 weeks out and I'm considering piking some up. not running any ASS

thanks a lot

 

[lukk3395]

I never got good results from t3 cause it increases your appetite and eats up hard earned gains.. Cycling clen or eca will give you better results.

I am already running clen at 60 mcg per day and tapering up right now. The T3 would be on top of that. Plus appetite is not a problem if I am hungry and am done with the food for the day I cry lol but getting stage ready isn't easy specially without AAS

 

[lukk3395]

thanks for all the info! I think I'm gonna run it at 25 mcg

 

[ChestRockwell]

25mcg is about the same as the average thyroid produces yes.

Well, not necessarily the case. It has been commonly cited on BB boards for eons that 25mcgs/day of T3 is a "replacement dose" and to be frank, I'm not exactly sure where this number came from?

However, newer studies are being conducted showing that this is far from accurate. In fact, true "replacement doses" might be much higher than this [1], upwards of 40mcgs/day of T3 combined with 115mcgs/day of T4.

Anecdotally, I've gotten comprehensive thyroid panels done while taking 25mcgs/day of T3 because I have a curious mind, and I was far from shut down.

Further, I have been advising folks for about a year or so that combined T4/T3 might be the way to go as there are potentially some T4-specific functions the body requires the hormone for. Running T3 solo means significant suppression of T4, leading to potential problems down the line. Some are significantly more sensitive to this than others...

1. Celi FS, Zemskova M, Linderman JD, et al. The pharmacodynamic equivalence of levothyroxine and liothyronine. A randomized, double blind, cross-over study in thyroidectomized patients. Clinical endocrinology. 2010;72(5):709-715.

 

[LordSamuilo]

Well, not necessarily the case. It has been commonly cited on BB boards for eons that 25mcgs/day of T3 is a "replacement dose" and to be frank, I'm not exactly sure where this number came from?

However, newer studies are being conducted showing that this is far from accurate. In fact, true "replacement doses" might be much higher than this [1], upwards of 40mcgs/day of T3 combined with 115mcgs/day of T4.

Anecdotally, I've gotten comprehensive thyroid panels done while taking 25mcgs/day of T3 because I have a curious mind, and I was far from shut down.

Further, I have been advising folks for about a year or so that combined T4/T3 might be the way to go as there are potentially some T4-specific functions the body requires the hormone for. Running T3 solo means significant suppression of T4, leading to potential problems down the line. Some are significantly more sensitive to this than others...

1. Celi FS, Zemskova M, Linderman JD, et al. The pharmacodynamic equivalence of levothyroxine and liothyronine. A randomized, double blind, cross-over study in thyroidectomized patients. Clinical endocrinology. 2010;72(5):709-715.

I'm by no means an expert when it comes to the thyroid , but if ones objective was to keep there metabolism from slowing down during extreme dieting due to down regulation of the thyroid , wouldnt simply using a t4 be more effective than playing the guessing game with t3 . as from my understanding t4 will only convert to t3 at the rate which your body can use it anyways ? So if your goal is only to keep your thyroid at normal functioning levels and not actually actually introduce superphysislogic levels of t3 into your body would t4 not be the better chose between the 2 ? Or is there some of other function of the thyroid that I'm over looking ?

 

[Docd187123]

Well, not necessarily the case. It has been commonly cited on BB boards for eons that 25mcgs/day of T3 is a "replacement dose" and to be frank, I'm not exactly sure where this number came from?

However, newer studies are being conducted showing that this is far from accurate. In fact, true "replacement doses" might be much higher than this [1], upwards of 40mcgs/day of T3 combined with 115mcgs/day of T4.

Anecdotally, I've gotten comprehensive thyroid panels done while taking 25mcgs/day of T3 because I have a curious mind, and I was far from shut down.

Further, I have been advising folks for about a year or so that combined T4/T3 might be the way to go as there are potentially some T4-specific functions the body requires the hormone for. Running T3 solo means significant suppression of T4, leading to potential problems down the line. Some are significantly more sensitive to this than others...

1. Celi FS, Zemskova M, Linderman JD, et al. The pharmacodynamic equivalence of levothyroxine and liothyronine. A randomized, double blind, cross-over study in thyroidectomized patients. Clinical endocrinology. 2010;72(5):709-715.

Correct me if I'm wrong but I think you misread the study you posted. The study was a crossover study measuring pharmacodynamic equivalence of T3 to T4 so that the patients took either T3 or T4 in the beginning, and than after inpatient testing and washout period they took the other hormone. So it's not that replacement doses are 40mcg of T3 plus 115mcg of T4 but it's that 40mcg T3 is equivalent pharmacodynamiclly to 115mcg of T3.

Again, I might be in error but bc of absorption issues, bioavailability, drug interactions, etc, a replacement dose of an exogenous hormone drug might not necessarily be the same as the endogenous production of that hormone.

Here is one study that states endogenous T3 production is 29mcg, 20% of which is made directly by the thyroid and the remaining 80% is made through peripheral tissues that convert T4 to T3

"Thyroxine (T4) is produced exclusively by the thyroid gland; its daily production rate is about 100 μg at an average body surface area of 1.79 m2 (56.2 μg/day/m2). Daily production rate of triiodothyronine (T3) for a body surface area of 1.79 m2 is about 29 μg (16 μg/day/m2): 20% (∼6 μg, or 3.3 μg/day/m2) is secreted by the thyroid gland, and 80% (∼23 μg, or 12.7 μg/day/m2) is generated in extrathyroidal tissues by 5′-deiodination of T4 [1]."

2012 ETA Guidelines: The Use of L-T4 + L-T3 in the Treatment of Hypothyroidism

 

[ChestRockwell]

but if ones objective was to keep there metabolism from slowing down during extreme dieting due to down regulation of the thyroid , wouldnt simply using a t4 be more effective than playing the guessing game with t3 .

If one's primary goal was to keep metabolic adaptations to dieting at a minimum, this can be done with dietary design to some degree. Remember, all individual components of TDEE go down during a diet and many hormones are also impacted.

With that said, before relying upon exogenous hormones (and I've been very vocal on other mediums that exogenous thyroid is not just something to play around with). The thyroidal axis is very complex and has a wide variety of impacts on the body, not just as it relates to metabolism.

Now, as far as your question, by supplementing only exogenous T4 you are relying upon your body's conversion process. It is well established that this conversion process does not work flawlessly in all individuals (deiodinase 2 (D2) enzyme issues) and so most feel that going straight to the active form (T3) takes a few steps out of the equation. However, as I said before, I think it could be a problem for some to not utilize both T4/T3 if deciding to go the exogenous route. In fact, this is becoming a more common discussion in medical journals as well [1-3] although far from unanimous...

1. Biondi B, Wartofsky L. Combination treatment with T4 and T3: toward personalized replacement therapy in hypothyroidism? J Clin Endocrinol Metab. 2012 Jul;97(7):2256-71
2. McDermott MT. Does combination T4 and T3 therapy make sense? Endocr Pract.
2012 Sep-Oct;18(5):750-7. doi: 10.4158/EP12076.RA. Review.
3. Wartofsky L. Combination L-T3 and L-T4 therapy for hypothyroidism. Curr Opin
Endocrinol Diabetes Obes. 2013 Oct;20(5):460-6.

 

[ChestRockwell]

Here is one study that states endogenous T3 production is 29mcg, 20% of which is made directly by the thyroid and the remaining 80% is made through peripheral tissues that convert T4 to T3

It appears they were citing this: Thyroidal and peripheral production of 3,5,3'-triiodothyronine in humans by multicompartmental analysis. - PubMed - NCBI

I'll have to make some time to read through the data but I think we can agree that endogenous T3 levels vary quite a bit and making blanket recommendations might not be ideal. Even in the study I cited earlier, the average was 40mcgs/day but had a +/- of 11mcgs.

In any event, thanks for that study, I hadn't seen it before and will add it to my repository...

 

[Docd187123]

It appears they were citing this: Thyroidal and peripheral production of 3,5,3'-triiodothyronine in humans by multicompartmental analysis. - PubMed - NCBI

I'll have to make some time to read through the data but I think we can agree that endogenous T3 levels vary quite a bit and making blanket recommendations might not be ideal. Even in the study I cited earlier, the average was 40mcgs/day but had a +/- of 11mcgs.

In any event, thanks for that study, I hadn't seen it before and will add it to my repository...

Yes I agree they vary quite a bit. Normally I say 25mcg as a general figure but I didn't write it out clear enough In this case.

Anytime man. I've gotten interesting studies from you so it's nice to be able to pay it forward.