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...Originally Posted by PMID: 9651103
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)Originally Posted by PMID: 9651103
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???
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10-05-2007, 05:19 AM #1
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3,3'-Diiodothyronine & 3,5-Diiodothyronine - Both T2 Thyroid Hormones
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10-05-2007, 05:29 AM #2
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10-05-2007, 09:22 AM #3
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10-05-2007, 09:32 AM #4
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10-05-2007, 04:12 PM #5
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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!!!
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10-05-2007, 06:33 PM #6
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Adv/Disadv of 3,5-T2 & 3,3'-T2
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?Last edited by 600538411; 10-05-2007 at 06:41 PM.
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10-05-2007, 06:39 PM #7
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10-06-2007, 03:08 AM #8
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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...
Originally Posted by PMID: 7298011Last edited by 600538411; 10-06-2007 at 04:58 PM.
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10-06-2007, 08:17 AM #9
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10-06-2007, 11:27 AM #10
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.
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10-06-2007, 11:40 AM #11
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10-06-2007, 12:13 PM #12
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10-06-2007, 12:17 PM #13
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Russell Wilson, the first QB in NFL history to throw a game-winning interception.
"So you got fired again eh?" "Yeah, they always freak out when you leave the scene of an accident."
Spiders are like offensive linemen, the best ones do their job and you never notice them.
An obvious example of New Math.
"It was a 2% tax hike, dumbass. From 3% to 5%"-NRKF84
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10-06-2007, 12:20 PM #14
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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.Russell Wilson, the first QB in NFL history to throw a game-winning interception.
"So you got fired again eh?" "Yeah, they always freak out when you leave the scene of an accident."
Spiders are like offensive linemen, the best ones do their job and you never notice them.
An obvious example of New Math.
"It was a 2% tax hike, dumbass. From 3% to 5%"-NRKF84
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10-07-2007, 02:19 AM #15
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Would be a combination of 3,5-T2 & 11-oxo I would suspect....
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
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....
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10-07-2007, 02:27 AM #16
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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....
3,5-T2
- SAN Thyrocuts II
- Hi-Tech Thyrozene (not exclusively though)
3,3-T2
-Gaspari ThyrotabsLast edited by 600538411; 10-07-2007 at 02:31 AM.
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11-09-2007, 03:15 PM #17
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11-09-2007, 09:13 PM #18
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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....Last edited by Supa Freek 420; 11-09-2007 at 09:18 PM.
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11-10-2007, 02:36 PM #19
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11-10-2007, 02:39 PM #20
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11-11-2007, 01:36 PM #23
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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....
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11-14-2007, 02:47 PM #24
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