3,3'-Diiodothyronine & 3,5-Diiodothyronine - Both T2 Thyroid Hormones

[600538411]

OK so I have seen some contradicting statements made about T2 thyroid hormone, more specifically that;

Administration of T2 does not effect the hypothalamic-pituitary-thyroid axis as much as T3 administration YET I read a study that mentioned;

T3 administration suppressed TSH by 88% compared to control. 3,5-T2 produced a similar effect suppressing the TSH level by about 75% compared to control; it thus reached values not significantly different from those of...T3-treated rats. By contrast, 3,3'-T2 had no effect on TSH, whatever the dose.

Yet over at T-Nation and other sites I have read that no suppression occurs... This is just one of the contradictions I have seen...

3,5-T2-treated hypothyroid rats showed increased serum GH levels at a dose of 10 microg/100 g BW (so 1mg/10kg) the level reached a value about 5-fold higher than that in hypothyroid rats. 3,3'-T2 did not affect GH levels whatever the dose.

When people seem to refer to T2, they refer to the readily available 3,5-Diiodothyronine and then take the positives from either 3,5-T2 or 3,3'-T2 varieties and make it a positive for 3,5-Diiodothyronine exclusively... (No TSH suppression, increases in serum GH, increases activation of G6PD, and decarboxylates oxidative phosphorylation in the mitochondria)

So I guess this leads to a question... Does 3,5-Diiodothyronine suppress TSH as much as T3?

Or at the end of the day which property is REALLY attributed to which configuration of T2 (3,3'-T2 or 3,5-T2)?

Food for thought, comments, couldn't care less???

[600538411]

Further is there any OTC version of 3,3'-Diiodothyronine? Called another name maybe?

What is the best / is there a supplement that restores TSH (so i guess a PCT for thyroid hormone)? Is there more than just E & Z Guggulsterones??

[DRP7]

OK so I have seen some contradicting statements made about T2 thyroid hormone, more specifically that;

Administration of T2 does not effect the hypothalamic-pituitary-thyroid axis as much as T3 administration YET I read a study that mentioned;



Yet over at T-Nation and other sites I have read that no suppression occurs... This is just one of the contradictions I have seen...



When people seem to refer to T2, they refer to the readily available 3,5-Diiodothyronine and then take the positives from either 3,5-T2 or 3,3'-T2 varieties and make it a positive for 3,5-Diiodothyronine exclusively... (No TSH suppression, increases in serum GH, increases activation of G6PD, and decarboxylates oxidative phosphorylation in the mitochondria)

So I guess this leads to a question... Does 3,5-Diiodothyronine suppress TSH as much as T3?

Or at the end of the day which property is REALLY attributed to which configuration of T2 (3,3'-T2 or 3,5-T2)?

Food for thought, comments, couldn't care less???

3,5' is suppressive on TSH, while 3,3' is apprently not. you have already quoted the relevant text on this issue (with the appropriate numbers). supplements containing 3,5' should thus be taken with some precaution and always be tapered off.

[bigkarl]

does anyone sell 3,3?

[600538411]

3,5' is suppressive on TSH, while 3,3' is apprently not. you have already quoted the relevant text on this issue (with the appropriate numbers). supplements containing 3,5' should thus be taken with some precaution and always be tapered off.

I was aware I had already answered one of my own questions, I was maybe looking for a conflicting study or so evidence that opposes this belief...

I have been making real good lean muscle mass gains whilst losing bodyfat at an equal rate (no real net weight loss) on a cutting cycle with 3,5-T2 & 11-oxo and I was really looking for the mechanism as to why when I realised that their were 2 different configurations of T2....

I really only wanted to use 3,5-T2 for its direct interection with the mitochondria and its ability to reduce efficiency of the electron transport chain (site of ATP formation)...

I am already 3 weeks into a cycle and now kinda pissed cause I chose to use it due to it NOT suppressing TSH and now I realise it is nearly just as much as T3, I am wondering how I am going to go about PCT!!!

[600538411]

From what I can tell from reading a fair few papers;

3,3'-Diiodothyronine
Advantages
* Almost no suppression of TSH/hypothalamic-pituitary-thyroid axis
* Stimulates cytochrome c oxidase - aka decouples Electron Transport Chain (slightly more than 3,5-T2)
* Precursor to T3 & T4 (which have their own metabolic properties of course)

Disadvantages
* Interferes with plasma membrane transport of T3
* No significant increases in growth hormone seen at any dosing levels

3,5-Diiodothyronine
Advantages
* Increases serum levels of growth hormone (GH) comprable to T3
* Stimulates cytochrome c oxidase - aka decouples Electron Transport Chain (slightly less than 3,3'-T2)
* Does not interfere with plasma membrane transport of T3
* Increases activation of Glucose-6-Phosphate Dehydrogenase

Disadvantages
* Suppression of TSH/hypothalamic-pituitary-thyroid axis is only slightly less but comprable to that of T3


Summary
If one is looking for strictly an increase in energy expenditure with less TSH depression, 3,3'-T2 is your answer..... If one is looking for more muscle mass preservation properties aswell and doesn't mind some TSH depression, 3,5-T2 is your answer....

On a final note though, I think T3 supplementation would probably be better than 3,5-T2 supplementation as serum 3,5-T2 as well as 3,3'-T2 concentrations have been shown to rise significantly with a marked rise in serum T3 following T3 administration. Also, just because T3 acts on the protein synthesis mechanism involved in the regulation of the mitochondrial mass (so is more indirect pathway) while both T2 act directly at the mitochondrial level, this doesn't mean it is less effective at interupting the ETC, in fact, T3 has been shown to exhibit slightly more of an effect even though it acts indirectly on the mitochondria....

Comments?

[600538411]

does anyone sell 3,3?

I found Gaspari Nutrition Thermogenic Thyrotabs use 3,3'-T2 (although they use a different nomeclature - 3,3P-iodo-4-(4-hydroxyphenoxy)-L-phenylalanine) Same ****e, different smell (or name even!)

Am kind of wishing I went with these over 3,5-T2 for my cycle now, doh!

[600538411]

Why this thread was moved from "supplement science" I do not know...

Another interesting issue;
Aspirin may also interact with a cycle utilising thyroid hormones. Salicyates are the backbone of aspirin and salicylates have been shown to alter the thyroid pathways... Read the following...

(following salicylate administration)... An immediate decrease of the thyroxine (T4) level in plasma to about 20% of original level and that of 3,5,3'-triiodothyronine (T3) to about 60% of that was found, while the level of 3,3',5'-triiodothyronine (rT3) was increased 20%. It was concluded that the administration of salicylate results in an immediate displacement of T4 and T3 from plasma protein binding and possibly inhibits the conversion of T4 to T3 and of rT3 to 3,3'-diiodothyronine which results in an increase of rT3 level in plasma. This might by partially prevented by an inhibiting effect of salicylate on the binding of rT3 to plasma proteins.

Whether this means a decrease in "metabolism" or an increase I do not know...

[Steve0178]

Great info in this thread...Bump for more people to read!

[DRP7]

Why this thread was moved from "supplement science" I do not know...

Another interesting issue;
Aspirin may also interact with a cycle utilising thyroid hormones. Salicyates are the backbone of aspirin and salicylates have been shown to alter the thyroid pathways... Read the following...



Whether this means a decrease in "metabolism" or an increase I do not know...

rT3 is the inactive Form of T3. By that, a salicylate-induced rapid conversion of T3 to rT3 will cause a drop of T3-mediated effects.

however, whether this will cause a drop in metabolism or not will depend on how long this effect lasts (possibly T3 levels could recover after an initial drop?) and on the fact whether salicylates will have additional effects than this one. e.g. it is a well known fact that aspirin has uncoupling effects on the mitochondrial electron chain - just like DNP, but many magnitudes of order less strong than DNP.

[gisnb]

I was aware I had already answered one of my own questions, I was maybe looking for a conflicting study or so evidence that opposes this belief...

I have been making real good lean muscle mass gains whilst losing bodyfat at an equal rate (no real net weight loss) on a cutting cycle with 3,5-T2 & 11-oxo and I was really looking for the mechanism as to why when I realised that their were 2 different configurations of T2....

I really only wanted to use 3,5-T2 for its direct interection with the mitochondria and its ability to reduce efficiency of the electron transport chain (site of ATP formation)...

I am already 3 weeks into a cycle and now kinda pissed cause I chose to use it due to it NOT suppressing TSH and now I realise it is nearly just as much as T3, I am wondering how I am going to go about PCT!!!

You've been gaining and losing fat equally? Is that the 3,5-T2 doing it? Does the Does the 3,3 do the samething?

What are the effects of TSH supression, and how do you stop it?

I know nothing about his stuff, so answers from anyone would be helpful...I'd love to gain while losing body fat.

[DRP7]

You've been gaining and losing fat equally? Is that the 3,5-T2 doing it? Does the Does the 3,3 do the samething?

What are the effects of TSH supression, and how do you stop it?

I know nothing about his stuff, so answers from anyone would be helpful...I'd love to gain while losing body fat.

suppression of TSH will reduce the natural production of T4/T3. so, when you stop taking 3,5'-T2, you might be at risk to have transiently lower than normal thyroid levels.

[ElMariachi]

suppression of TSH will reduce the natural production of T4/T3. so, when you stop taking 3,5'-T2, you might be at risk to have transiently lower than normal thyroid levels.

That is why it would be a good idea to follow up any 3'5 products(Thyrocuts II) with things like Coleus, 7-Keto and L-Tyrosine.

[ElMariachi]

It would be cool to make up a list of the various 3,3 and 3,5 products as well.


I know that Thyrocuts II from San and Thyrozene from Hi-Tech are both 3,5 compounds.

[600538411]

You've been gaining and losing fat equally? Is that the 3,5-T2 doing it?

Would be a combination of 3,5-T2 & 11-oxo I would suspect....

Does the Does the 3,3 do the samething?

No, It won't maintain lean muscle mass/increase lean muscle mass as it does not cause an increase in "growth hormone", that would be the mechanism causing lean muscle gains

What are the effects of TSH supression, and how do you stop it?

Depends how much it is suppressed really...

If MILDLY suppresed you would most likely just put on weight relatively easy so diet would have to be in check....

If EXTREMELY suppressed you could expect any of the following; Fatigue, Depression, Modest weight gain, Cold intolerance, Excessive sleepiness, Dry & coarse hair, Constipation, Dry skin, Muscle cramps, Increased cholesterol levels, Decreased concentration, Vague aches and pains, Swelling of the legs....

[600538411]

That is why it would be a good idea to follow up any 3'5 products(Thyrocuts II) with things like Coleus, 7-Keto and L-Tyrosine.

Hmmm. What if I am having all three of them on my 3,5-T2 cycle aswell lol!!!

I am also taking Coleus, Methyl-7-Keto and L-Tyrosine as it is in Tight! Hardcore which is part of my cycle....

It would be cool to make up a list of the various 3,3 and 3,5 products as well.

I know that Thyrocuts II from San and Thyrozene from Hi-Tech are both 3,5 compounds.

3,5-T2
- SAN Thyrocuts II
- Hi-Tech Thyrozene (not exclusively though)

3,3-T2
-Gaspari Thyrotabs

[gisnb]

What's a safe 3,5 dose to prevent suppression?

[SupaNatural]

I did not know Thyrotabs was 3,3 diiodothyronine but I know 3,3 is one of the isomers in Dicana.

I may be thrown off by the nomenclature but TT appears to be a phenylalanine derivative? Then again the definition of thyronine is an amino acid thats occurs in proteins only in the form of iodinated derivatives, hmmmmmmmm....

[600538411]

What's a safe 3,5 dose to prevent suppression?

I took two whole bottles in a row (upton 6/day at peak) and can say the suppression is there at the end (I say this from how I felt, not bloodworking)... I was slow for about a week or so but I just compensated by keeping my diet in check and using epistane of the back end...

[600538411]

I did not know Thyrotabs was 3,3 diiodothyronine but I know 3,3 is one of the isomers in Dicana.

I may be thrown off by the nomenclature but TT appears to be a phenylalanine derivative? Then again the definition of thyronine is an amino acid thats occurs in proteins only in the form of iodinated derivatives, hmmmmmmmm....

Alot of hormonal pathways are controlled by peptides and peptides are generally some variations of amino acids so it shouldn't be too much of a suprise.... But yeah thyroid hormone is one of the simpler ones that is for sure... Wouldn't be too hard to synthesise

[ForceLineBacker]

marked

[kappaz]

600538411, what is your opinion on 3,5 Diiodo-L-Tyrosine?

[600538411]

600538411, what is your opinion on 3,5 Diiodo-L-Tyrosine?

Hmmm... I think it is OK.... It would be most suitable for say someone who has been already dieting and has made ground to say 10%-12% bf and their metabolism was slowing down from say 6-8 weeks of serious dieting... Then it would probably be a good synergist with something like YCA....

It does suppress TSH though no doubt and since I am pretty sure it is not a precursor to T3, more so a product that is derived from T3 (irreversibly? - From what I have read in leterature, pathways are yet to be determined)...

Where as 3,3'-T2 is a direct precursor to T3 so although 3,3'-T2 does not have a direct action on the mitochondria like 3,5-T2 and supposedly does not suppress TSH, it may then be suppressive by the fact that it leads to increases in T3 which would then be suppressive....

I believe probably a two pronged approach would be the best bet here... Both 3,5-T2 for its direct action on proton leakage and 3,3'-T2 so that basal levels of T3 down fall away too as supplementation continues...

BUT to answer you question directly... 3,5-T2 is pretty good (if used synergistically with something else working on adrenergic receptors) BUT there are probably better choices as a standalone....

[blind12]

It does suppress TSH though no doubt and since I am pretty sure it is not a precursor to T3, more so a product that is derived from T3 (irreversibly? - From what I have read in leterature, pathways are yet to be determined)...

Erm, 3,5-Diiodo-L-Tyrosine is definitely intended to be a precursor to T4 and subsequently T3 ? It's the L-Tyrosine with two iodine atoms attached. Product ads say it provides the thyroid with iodine and tyrosine. Not sure if it is any better than plain L-Tyrosine.

[SupaNatural]

Erm, 3,5-Diiodo-L-Tyrosine is definitely intended to be a precursor to T4 and subsequently T3 ? It's the L-Tyrosine with two iodine atoms attached. Product ads say it provides the thyroid with iodine and tyrosine. Not sure if it is any better than plain L-Tyrosine.

I'm pretty sure the post you quoted was in regards to 3,5 diiodo thyronine and not 3,5-Diiodo-L-Tyrosine. I've used a NYC stack with and without 3,5-Diiodo-L-Tyrosine and did not notice any difference.

[deserusan]

Thyrotabs is not a T2 analogue.

[blind12]

I'm pretty sure the post you quoted was in regards to 3,5 diiodo thyronine and not 3,5-Diiodo-L-Tyrosine.

It was an answer to a question on 3,5-Diiodo-L-Tyrosine. It's right above my post

[blind12]

Thyrotabs is not a T2 analogue.

It's a 3,3'-T2.
There are many ways to write down a formula

[SupaNatural]

It was an answer to a question on 3,5-Diiodo-L-Tyrosine. It's right above my post

I saw that, I missed it initially and thought the question was about 3'5-T2. But I'm sure the answer was in regards to 3'5-T2 even though the question was in regards to 3,5-Diiodo-L-Tyrosine.

[deserusan]

It's a 3,3'-T2.
There are many ways to write down a formula

I agree there are many ways to write a formula, however your focus on the 3, 3 prime is bit off.