Does T4-T3 stop natural thyroid production?
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outlawtas
New member
yes, it will shut down your thyroid...though there is the belief and 12.5mcg will supplement, as oppose to replace, your thryoid. But at that dosage I wouldn't count on too much in the way of weightloss more use that dosage to prevent fat gain while bulking and increasing protein synthesis.
outlawtas
New member
This is just one article...
By: Anthony Roberts
Cytomel
(Liothyrine Sodium )
This drug is a synthetic T3 hormone. As you may already know, most natural T3 is not produced directly by your thyroid gland, but rather is converted from the T4 thyroid hormone. (8)
Natural T3 is a regulator of the oxidative metabolism of energy producing substrates (food or stored substrates like fat, muscle, and glycogen) by the mitochondria. The mitochondria, as you will recall from your high school biology class, are usually referred to as the "cell's powerhouses" because they produce ATP. Taking Cytomel (supplemental T3) greatly increases the uptake of nutrients into the mitochondria and also their oxidation rate (i.e. the rate at which they are burned for energy), by increasing the activities of the enzymes involved in the oxidative metabolic pathway. Everything is working harder, in other words, and more fuel is needed to supplement this increased work rate. Therefore, as you can guess, taking supplemental Cytomel will increase your body’s energy demands. And if you are in a hypocaloric state, you will begin burning even more fat primarily due to an increase in ATP. This increased ATP causes an increase in overall metabolic activity. (8)(9)This is exactly what we want, and is why we would be taking thyroid hormones like Cytomel in the first place. If you aren’t taking anabolic steroids with your Cytomel, however, your body may start to eat away muscle to provide energy for you to function. Remember mitochondria/ATP aren’t very picky, but they are very efficient. What I mean by this is that they will use whatever is on hand to generate energy for your body to continue functioning…fat, protein, glucose….it doesn’t matter to ATP, as long as there’s something to give them energy. Taking this drug will increase their need to find something to burn to create this energy. Ergo, if we aren’t taking anabolic steroids while taking our T3, we may lose too much muscle, especially while dieting.
Thus we can see that there are many advantages to using Cytomel to optimize our metabolic rate. It will also increase your body’s ability to synthesize protein, but from what I’ve seen personally, it acts as a catabolic when it isn’t administered with anabolic steroids. It is often the last thing added into a precontest diet, as it has a reputation for getting rid of the last few percentages of bodyfat…the “sticky fat” as it’s called in bodybuilding…the fat that just doesn’t want to leave you in the last few weeks of dieting. I think this is a poor use for this drug, and that it should be the first thing added into a diet to lose fat, as it will optimize your metabolic rate, which should be done at the outset of a diet, not after the calorie restriction has diminished your thyroid output and you are adding it in simply to replace what was lost.
Unfortunately, in all of the studies I’ve seen, T3 also increased growth hormone production. (5)(6) As we all know, GH is also a strongly lipolytic compound, and this is another mechanism by which T3 may exert it’s effects, although I suspect this would only be a small percentage of it’s overall effects. This being the case, it has always been somewhat problematic to me to note that when GH and T3 are used together, the increased nitrogen retention normally found with GH use is negated. (7). If you were only using T3 and GH this may be a problem, but as I’ve already stated, you are going to need some anabolic agents if you are using T3. And as you have read previously, I recommend the veritable anabolic/lipolytic orgy of Insulin, T3, Anabolic Steroids, GH, and insulin, for 100% maximum results in minimal time
On the brighter side, and of special note to dieters, administration of T3 has been shown to upregulate the beta 2 receptors in fat tissue. As you know clenbuterol and similar compounds downregulate this receptor, so using T3 with your clen will help stave off or reverse this downregulation. (1)(2)(3)(4). I would still recommend taking your benadryl every third week, though.
Finally, I would like to address the issue of recovery of your natural thyroid function after you stop taking cytomel. The horror stories of people on permanent thyroid replacement just aren’t true. I remember a few years ago, the rumor was circulating that the current Ms.Fitness had permanently shut off her thyroid gland, and was now fat and on thyroid hormone permanently. This is just another horror story based in nothing but conjecture and rumour…the studies I’ve looked at have shown people recovering their thyroid hormone relatively quickly (within months, at most) after going off of several YEARS (!) of thyroid replacement therapy (10)(11). I speculate that you can optimize your metabolic rate with Cytomel for 9-10 months a year, and just normalize yourself for 2-3 months (perhaps the winter, when you are mostly covered up), and then go right back on. Some people in the studies I read were on T3 for 30 years and recovered their natural thyroid function within short order. I think we can safely spend an athletic career using Cytomel 9-10 months out of the year, and just taking those few months off to normalize ourselves. Is this aggressive? Yes. Unsafe? NO.
References:
1. Catecholamines inhibit Ca(2+)-dependent proteolysis in rat skeletal muscle through beta(2)-adrenoceptors and cAMP. Navegantes LC, Resano NM, Migliorini RH, Kettelhut IC Am J Physiol Endocrinol Metab 2001 Sep;281(3):E449-54
2. Regulation of human adipocyte gene expression by thyroid hormone J Clin Endocrinol Metab 2002 Feb;87(2):630-4 Viguerie N, Millet L, Avizou S, Vidal H, Larrouy D, Langin D.
3. Alpha 2- and beta-adrenergic receptor binding and action in gluteal adipocytes from patients with hypothyroidism and hyperthyroidism Metabolism 1987 Nov;36(11):1031-9 Richelsen B, Sorensen NS
4. Regulation of beta 1- and beta 3-adrenergic agonist-stimulated lipolytic response in hyperthyroid and hypothyroid rat white adipocytes Br J Pharmacol 2000 Feb;129(3):448-56. Germack R, Starzec A, Perret GY
5. Role of thyroid hormone in the control of growth hormone gene expression Braz J Med Biol Res 1994 May;27(5):1269-72. Volpato CB, Nunes MT.
6. Low-dose T(3) improves the bed rest model of simulated weightlessness in men and women. Am J Physiol 1999 Aug;277(2 Pt 1):E370-9 Lovejoy JC, Smith SR, Zachwieja JJ, Bray GA, Windhauser MM, Wickersham PJ, Veldhuis JD, Tulley R, de la Bretonne JA.
7. Effects of long-term growth hormone (GH) and triiodothyronine (T3) administration on functional hepatic nitrogen clearance in normal man. Wolthers T, Grofte T, Moller N, Vilstrup H, Jorgensen JO.
J Hepatol 1996 Mar;24(3):313-9
8. Human Anatomy and Physiology, 6th Edition. John w. Hole jr.
9. Physicians Desk Reference
10. Recovery of pituitary thyrotropic function after withdrawal of prolonged thyroid-suppression therapy. N Engl J Med 1975 Oct 2;293(14):681-4 Vagenakis AG, Braverman LE, Azizi F, Portinay GI, Ingbar SH.
11. Patterns off recovery of the hypothalamic-pituitary-thyroid axis in patients taken of chronic thyroid therapy. J Clin Endocrinol Metab 1975 Jul;41(1):70-80 Krugman LG, Hershman JM, Chopra IJ, Levine GA, Pekary E, Geffner DL, Chua Teco GN
By: Anthony Roberts
Cytomel
(Liothyrine Sodium )
This drug is a synthetic T3 hormone. As you may already know, most natural T3 is not produced directly by your thyroid gland, but rather is converted from the T4 thyroid hormone. (8)
Natural T3 is a regulator of the oxidative metabolism of energy producing substrates (food or stored substrates like fat, muscle, and glycogen) by the mitochondria. The mitochondria, as you will recall from your high school biology class, are usually referred to as the "cell's powerhouses" because they produce ATP. Taking Cytomel (supplemental T3) greatly increases the uptake of nutrients into the mitochondria and also their oxidation rate (i.e. the rate at which they are burned for energy), by increasing the activities of the enzymes involved in the oxidative metabolic pathway. Everything is working harder, in other words, and more fuel is needed to supplement this increased work rate. Therefore, as you can guess, taking supplemental Cytomel will increase your body’s energy demands. And if you are in a hypocaloric state, you will begin burning even more fat primarily due to an increase in ATP. This increased ATP causes an increase in overall metabolic activity. (8)(9)This is exactly what we want, and is why we would be taking thyroid hormones like Cytomel in the first place. If you aren’t taking anabolic steroids with your Cytomel, however, your body may start to eat away muscle to provide energy for you to function. Remember mitochondria/ATP aren’t very picky, but they are very efficient. What I mean by this is that they will use whatever is on hand to generate energy for your body to continue functioning…fat, protein, glucose….it doesn’t matter to ATP, as long as there’s something to give them energy. Taking this drug will increase their need to find something to burn to create this energy. Ergo, if we aren’t taking anabolic steroids while taking our T3, we may lose too much muscle, especially while dieting.
Thus we can see that there are many advantages to using Cytomel to optimize our metabolic rate. It will also increase your body’s ability to synthesize protein, but from what I’ve seen personally, it acts as a catabolic when it isn’t administered with anabolic steroids. It is often the last thing added into a precontest diet, as it has a reputation for getting rid of the last few percentages of bodyfat…the “sticky fat” as it’s called in bodybuilding…the fat that just doesn’t want to leave you in the last few weeks of dieting. I think this is a poor use for this drug, and that it should be the first thing added into a diet to lose fat, as it will optimize your metabolic rate, which should be done at the outset of a diet, not after the calorie restriction has diminished your thyroid output and you are adding it in simply to replace what was lost.
Unfortunately, in all of the studies I’ve seen, T3 also increased growth hormone production. (5)(6) As we all know, GH is also a strongly lipolytic compound, and this is another mechanism by which T3 may exert it’s effects, although I suspect this would only be a small percentage of it’s overall effects. This being the case, it has always been somewhat problematic to me to note that when GH and T3 are used together, the increased nitrogen retention normally found with GH use is negated. (7). If you were only using T3 and GH this may be a problem, but as I’ve already stated, you are going to need some anabolic agents if you are using T3. And as you have read previously, I recommend the veritable anabolic/lipolytic orgy of Insulin, T3, Anabolic Steroids, GH, and insulin, for 100% maximum results in minimal time
On the brighter side, and of special note to dieters, administration of T3 has been shown to upregulate the beta 2 receptors in fat tissue. As you know clenbuterol and similar compounds downregulate this receptor, so using T3 with your clen will help stave off or reverse this downregulation. (1)(2)(3)(4). I would still recommend taking your benadryl every third week, though.
Finally, I would like to address the issue of recovery of your natural thyroid function after you stop taking cytomel. The horror stories of people on permanent thyroid replacement just aren’t true. I remember a few years ago, the rumor was circulating that the current Ms.Fitness had permanently shut off her thyroid gland, and was now fat and on thyroid hormone permanently. This is just another horror story based in nothing but conjecture and rumour…the studies I’ve looked at have shown people recovering their thyroid hormone relatively quickly (within months, at most) after going off of several YEARS (!) of thyroid replacement therapy (10)(11). I speculate that you can optimize your metabolic rate with Cytomel for 9-10 months a year, and just normalize yourself for 2-3 months (perhaps the winter, when you are mostly covered up), and then go right back on. Some people in the studies I read were on T3 for 30 years and recovered their natural thyroid function within short order. I think we can safely spend an athletic career using Cytomel 9-10 months out of the year, and just taking those few months off to normalize ourselves. Is this aggressive? Yes. Unsafe? NO.
References:
1. Catecholamines inhibit Ca(2+)-dependent proteolysis in rat skeletal muscle through beta(2)-adrenoceptors and cAMP. Navegantes LC, Resano NM, Migliorini RH, Kettelhut IC Am J Physiol Endocrinol Metab 2001 Sep;281(3):E449-54
2. Regulation of human adipocyte gene expression by thyroid hormone J Clin Endocrinol Metab 2002 Feb;87(2):630-4 Viguerie N, Millet L, Avizou S, Vidal H, Larrouy D, Langin D.
3. Alpha 2- and beta-adrenergic receptor binding and action in gluteal adipocytes from patients with hypothyroidism and hyperthyroidism Metabolism 1987 Nov;36(11):1031-9 Richelsen B, Sorensen NS
4. Regulation of beta 1- and beta 3-adrenergic agonist-stimulated lipolytic response in hyperthyroid and hypothyroid rat white adipocytes Br J Pharmacol 2000 Feb;129(3):448-56. Germack R, Starzec A, Perret GY
5. Role of thyroid hormone in the control of growth hormone gene expression Braz J Med Biol Res 1994 May;27(5):1269-72. Volpato CB, Nunes MT.
6. Low-dose T(3) improves the bed rest model of simulated weightlessness in men and women. Am J Physiol 1999 Aug;277(2 Pt 1):E370-9 Lovejoy JC, Smith SR, Zachwieja JJ, Bray GA, Windhauser MM, Wickersham PJ, Veldhuis JD, Tulley R, de la Bretonne JA.
7. Effects of long-term growth hormone (GH) and triiodothyronine (T3) administration on functional hepatic nitrogen clearance in normal man. Wolthers T, Grofte T, Moller N, Vilstrup H, Jorgensen JO.
J Hepatol 1996 Mar;24(3):313-9
8. Human Anatomy and Physiology, 6th Edition. John w. Hole jr.
9. Physicians Desk Reference
10. Recovery of pituitary thyrotropic function after withdrawal of prolonged thyroid-suppression therapy. N Engl J Med 1975 Oct 2;293(14):681-4 Vagenakis AG, Braverman LE, Azizi F, Portinay GI, Ingbar SH.
11. Patterns off recovery of the hypothalamic-pituitary-thyroid axis in patients taken of chronic thyroid therapy. J Clin Endocrinol Metab 1975 Jul;41(1):70-80 Krugman LG, Hershman JM, Chopra IJ, Levine GA, Pekary E, Geffner DL, Chua Teco GN
T3 is the functioning hormone that your pituitary demands and the body provides. Essentially, T4 acts as storage.
Yes. It can dramatically decrease your natural request for T4 and T3 when you do not have a deficiency and supplement anyway. (I like to use the example of why you don't grocery shop while hungry...you don't crave food right after you've eaten...)
You can absolutely do permanent damage, and believe me (I deal with it daily)- it's not something you want. You'll have much more issue mentally, emotionally and physically than if you just chose a different route.
You can also become hyperthyroid for a time (palpitations, sweating, weight loss, insomnia, energy), and then your body will essentially tire itself and turn the opposite (hair loss, weight gain, lethargy, brain fog, slow heartbeat).
It's just not worth the risk in my opinion.
And for those hell bent on taking T3 anyway, you should not take the rule of thumb that it's a one dose fits all. It's by individual weight that it is prescribed, so you might want to take that into consideration.
Yes. It can dramatically decrease your natural request for T4 and T3 when you do not have a deficiency and supplement anyway. (I like to use the example of why you don't grocery shop while hungry...you don't crave food right after you've eaten...)
You can absolutely do permanent damage, and believe me (I deal with it daily)- it's not something you want. You'll have much more issue mentally, emotionally and physically than if you just chose a different route.
You can also become hyperthyroid for a time (palpitations, sweating, weight loss, insomnia, energy), and then your body will essentially tire itself and turn the opposite (hair loss, weight gain, lethargy, brain fog, slow heartbeat).
It's just not worth the risk in my opinion.
And for those hell bent on taking T3 anyway, you should not take the rule of thumb that it's a one dose fits all. It's by individual weight that it is prescribed, so you might want to take that into consideration.
Lol, you dug up a post more than 10 years old! But I had taken T3 on it's own last year @ 50mcg was the same as normal for me, 62.5 mcg started burning fat at a good rate, 75 mcg turned my quads into mush, I freaked out and stopped, I suffered insomnia for roughly 6 months after, was the worst i've felt, probably ever, however I did have a lot of shit going on, but i'm sure the t3 didn't help, best avoided IMO, at least I found a legit source though.
appleton111
New member
thanks for sharing.
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