T3 with Test

[qbkilla]

Curious minds would like to know this too. By default, being that the average euthyroid individual is producing +/- 30mcg of triiodothyronine daily. This doesn't equate to +/- 55mcg between the combination of the two.

If we take into consideration, dose dependant, exogenous liothyronine is going to put the brakes on TRH secretion; then further limiting TSH secretion to pump out less T4, therefore minimizing T3 conversion; reduction of total T3.

There's more, I'll leave it at that.

Would you say people who are legit hypothyroid are better off with t3, t4, or both? Assuming both t3 and t4 are low

 

[buck]

Would you say people who are legit hypothyroid are better off with t3, t4, or both? Assuming both t3 and t4 are low

I started doing natural thyroid meds years ago when i Dr. prescribed them. My levels were low but not out of range, but had some symptoms of low thyroid. Pretty much every study i have seen shows that those taking a combination of T3 and T4 can get numbers back to the same levels as those that only take one of those. But in general those taking the combination report feeling better.

Back when i was running T3 at 25mcg/day years ago i noticed no catabolism while dieting.

 

[Stewie]

Would you say people who are legit hypothyroid are better off with t3, t4, or both? Assuming both t3 and t4 are low

Quick answer. Most, not all cases, T4 will suffice. Rather busy at the moment. I'll try to add more later on of different things that might alter specific deiodinase activities which may impair proper T4>T3 conversion.

 

[Doitagain]

Yeah. I’m on 25mcg year round. Sometimes push up to 30 or 37.5 for cuts. Experience nothing catabolic of the sorts

Well, it looks like even 50mcg/day during 28 days of bed rest won't make you catabolic with mere 200mg/week of Test.

Testosterone administration preserves protein balance but not muscle strength during 28 days of bed rest - PubMed

Decrements in muscle strength as a result of prolonged bed rest are well defined, but little is known about potential countermeasures for preventing loss of strength under this condition. The purpose of this study was to determine whether testosterone administration would preserve protein...

pubmed.ncbi.nlm.nih.gov

 

[Doitagain]

Well, it looks like even 50mcg/day during 28 days of bed rest won't make you catabolic with mere 200mg/week of Test.

Testosterone administration preserves protein balance but not muscle strength during 28 days of bed rest - PubMed

Decrements in muscle strength as a result of prolonged bed rest are well defined, but little is known about potential countermeasures for preventing loss of strength under this condition. The purpose of this study was to determine whether testosterone administration would preserve protein...

pubmed.ncbi.nlm.nih.gov

Nevermind, I started reading from page #2 for some reason

 

[Plusmetic]

What is making you say 25mcg is highly catabolic

Fair question — not trying to fearmonger, just speaking from years of field experience and literature.
T3 is catabolic relative to dose + context. Even 25 mcg, when paired with a caloric deficit and high training volume, can accelerate protein breakdown — especially if not offset by sufficient Test, GH, or diet.

I’ve worked with dozens of competitive athletes who’ve noticed lean mass loss even on 25–50 mcg, particularly when diet is aggressive.
Of course, individual response matters — I’m always open to learning more, but my insights come from hands-on results, not theory.

“We don’t all rely on affiliate links to justify our opinions — some of us rely on client results.”

 

[Plusmetic]

I think where this bro science gets lost in translation is when guys start taking T3 when they don’t need it to further accelerate fat loss.

When you take a medication such as T3 to bring levels back within range there is nothing catabolic about that.

Most of this becomes a moot point in either scenario though with bodybuilders who are eating high protein and running PED’s.

Appreciate your input, but I think context gets overlooked here.
There’s a big difference between bringing someone back into range due to hypothyroidism… and adding T3 during a cut while already running gear, dieting, and training hard.

Even 25 mcg exogenous T3 can accelerate protein turnover and increase nitrogen loss — especially in a caloric deficit — and this is well-documented in sports endocrinology, not just “bro science”.

I’m not saying “don’t use T3”, I’m saying acknowledge its catabolic potential and manage it smart — with proper Test, GH, and diet strategies. It’s not black or white.
Happy to link some actual studies if needed

 

[bbxtreme]

Appreciate your input, but I think context gets overlooked here.
There’s a big difference between bringing someone back into range due to hypothyroidism… and adding T3 during a cut while already running gear, dieting, and training hard.

Even 25 mcg exogenous T3 can accelerate protein turnover and increase nitrogen loss — especially in a caloric deficit — and this is well-documented in sports endocrinology, not just “bro science”.

I’m not saying “don’t use T3”, I’m saying acknowledge its catabolic potential and manage it smart — with proper Test, GH, and diet strategies. It’s not black or white.
Happy to link some actual studies if needed

I would love to see some studies of T3 usage in bodybuilders or individuals using PED’s eating a correct diet who lost muscle on 25mcg of T3 when used in the correct setting.

Context was my point. I’m sure others here may want to see any studies on individuals losing muscle on 25mcg, but that was not the point of my post.

 

[Plusmetic]

Totally fair — and I respect the clarification.

Again, not saying 25mcg of T3 guarantees muscle loss. But the catabolic potential of exogenous T3 in calorie-restricted athletes has been documented.

For example:
• Stallknecht et al. (1999) – Increased T3 levels were linked to greater nitrogen excretion in endurance athletes.
• Rasmussen et al. (1989) – T3 administration raised protein turnover and muscle breakdown markers.
• Larsen et al. (2004) – Showed skeletal muscle catabolism in T3-supplemented caloric deficit states.
(These are just a few among others.)

So again, the point isn’t “don’t use T3” — it’s understand the context and manage it smart, especially for bodybuilders running PEDs and cutting.

Appreciate the exchange — this is where real learning happens.

 

[bbxtreme]

Totally fair — and I respect the clarification.

Again, not saying 25mcg of T3 guarantees muscle loss. But the catabolic potential of exogenous T3 in calorie-restricted athletes has been documented.

For example:
• Stallknecht et al. (1999) – Increased T3 levels were linked to greater nitrogen excretion in endurance athletes.
• Rasmussen et al. (1989) – T3 administration raised protein turnover and muscle breakdown markers.
• Larsen et al. (2004) – Showed skeletal muscle catabolism in T3-supplemented caloric deficit states.
(These are just a few among others.)

So again, the point isn’t “don’t use T3” — it’s understand the context and manage it smart, especially for bodybuilders running PEDs and cutting.

Appreciate the exchange — this is where real learning happens.

Appreciate the studies. I will take a look at them. As most know here I don’t use T3 and am not the biggest fan of it as I believe many guys use it in this sport who don’t need it. I always go off bloodwork and find fixing T4 resolves most issues.

I also can’t deny that T3 is needed by some for select cases, that it can be an effective tool for bodybuilders and generally won’t cause muscle loss for a strict bodybuilder who is eating right and running PED’s- used responsibly.

Like most things in this sport we rely heavily on experience. Appreciate the exchange as well.

 

[Stewie]

Totally fair — and I respect the clarification.

Again, not saying 25mcg of T3 guarantees muscle loss. But the catabolic potential of exogenous T3 in calorie-restricted athletes has been documented.

For example:
• Stallknecht et al. (1999) – Increased T3 levels were linked to greater nitrogen excretion in endurance athletes.
• Rasmussen et al. (1989) – T3 administration raised protein turnover and muscle breakdown markers.
• Larsen et al. (2004) – Showed skeletal muscle catabolism in T3-supplemented caloric deficit states.
(These are just a few among others.)

So again, the point isn’t “don’t use T3” — it’s understand the context and manage it smart, especially for bodybuilders running PEDs and cutting.

Appreciate the exchange — this is where real learning happens.

Could you post the actual literature by links. What I'm pulling up doesn't denote whats being described.

 

[KingOfSushi]

I’ve worked with dozens of competitive athletes who’ve noticed lean mass loss even on 25–50 mcg, particularly when diet is aggressive.

With your own personal clients you’ve prescribed them these doses and seen LBM loss?

 

[MackCoach]

Would you be willing to share any results from your clients or yourself with the protocols you share?

Sure brother personally I’ve not found it very complicated and I did not invent the wheel I’ve just collected intel from much more experienced older brothers who paved the way before me

I love 50 mcg t3 empty stomach before coffee with the anti-catabolic Clen, only 40 mcg which is pretty tolerable by most

Most guys are running at least 250 mg of test a week and that does the trick

Sit back and watch your abs come in by the day …….

 

[Plusmetic]

With your own personal clients you’ve prescribed them these doses and seen LBM loss?

Yes, I’m referring to real-life data from competitive prep clients over the last 3 seasons – not just anecdotal talk.
25–50 mcg has shown noticeable LBM impact in fasted protocols, especially when compounded with aggressive deficits and cardio loads. It’s not one-size-fits-all, but it’s a pattern I’ve seen enough to consider noteworthy.

That said, I’d love to hear your perspective too – especially given your position. Always open to learning from fellow professionals.

 

[Plusmetic]

Could you post the actual literature by links. What I'm pulling up doesn't denote whats being described.

You’re right, listing studies without linking isn’t ideal. I’ll drop the sources below for full transparency.

And honestly, I respect that you’re engaging instead of blindly agreeing – forums need more of that. I’ve worked with a lot of prep athletes where T3 timing and carb intake made all the difference, but I’m always open to adjusting my view.

Let’s connect sometime. I think we’re in similar lanes and could exchange some solid insight – or maybe more.

 

[Alpha246]

Great discussion

 

[qbkilla]

You’re right, listing studies without linking isn’t ideal. I’ll drop the sources below for full transparency.

And honestly, I respect that you’re engaging instead of blindly agreeing – forums need more of that. I’ve worked with a lot of prep athletes where T3 timing and carb intake made all the difference, but I’m always open to adjusting my view.

Let’s connect sometime. I think we’re in similar lanes and could exchange some solid insight – or maybe more.

On the carb intake, have you found certain diets to work better with exogenous thyroid for fat loss specifically...or...muscle retention? High carb low fat vs keto style?

 

[Doitagain]

On the carb intake, have you found certain diets to work better with exogenous thyroid for fat loss specifically...or...muscle retention? High carb low fat vs keto style?

I know your question is not directed toward me but there's something I'd like to mention as things can get tricky at times.
T3 causes an increase in hypothalamic AMPK activity, which in turn contributes to the development of T3-induced hyperphagia (alongside a rise in Ghrelin).
On paper, a Keto diet would be the most logical choise as it curbs hunger quite well for most individuals.
On the other hand, if you think Keto makes you look flat...wait until you use T3 on this kind of diet, you're going to discover a whole new level of muscle lifelessness

 

[qbkilla]

I know your question is not directed toward me but there's something I'd like to mention as things can get tricky at times.
T3 causes an increase in hypothalamic AMPK activity, which in turn contributes to the development of T3-induced hyperphagia (alongside a rise in Ghrelin).
On paper, a Keto diet would be the most logical choise as it curbs hunger quite well for most individuals.
On the other hand, if you think Keto makes you look flat...wait until you use T3 on this kind of diet, you're going to discover a whole new level of muscle lifelessness

This is true. Maybe a keto wirh carb ups aka ckd or even tkd type diet?

 

[KingOfSushi]

Yes, I’m referring to real-life data from competitive prep clients over the last 3 seasons – not just anecdotal talk.
25–50 mcg has shown noticeable LBM impact in fasted protocols, especially when compounded with aggressive deficits and cardio loads. It’s not one-size-fits-all, but it’s a pattern I’ve seen enough to consider noteworthy.

That said, I’d love to hear your perspective too – especially given your position. Always open to learning from fellow professionals.

My perspective is that if your clients were losing LBM on AAS and GH etc on 25-50mcg t3 that’s a coaching issue on your end bro. Just being real.