'Natural' Levels vs TRT Levels?

Let’s say, hypothetically speaking, someone on TRT has a T level of 1000. His identical twin brother has a natural T level of 1000. Will there be any difference in muscle building potential, muscle proteïne syntesis and/or body composition after some time?

In other words; provides TRT benefits over natural T levels regarding body composition and excersise performance?

Trying to finds studies, but can’t find them…

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Define “1000” (assuming you are referring to 1000 ng/dl) with TRT vs “1000” natural.

As properly measured 1000 natural would be peak. 1000 on TRT could be (often is) trough. Is that trough with weekly injection, E3.5D injection, EOD injection, ED injection?

The mean TT levels for those 4 TRT cases are different and considerably higher than the mean natural levels by 30 to 100%+. Typical mean level for a natural with 1000 peak would be 600 to 800 ng/dl.

Important to define properly. Hence “1000 TRT” would likely give much more area under curve than “1000 natural” and why some guys get considerable side effects on “TRT”. They also carry more muscle with same bodyfat level (positive or negative depending on how you look at it).

Hence don’t confuse your natural peak with your TRT trough. Very different animals.

More info to convert between peak/mean/trough level on injectable T cypionate:


Hourly variation in TT level for natural:


Obviously treatment above changes with different T delivery method and its pharmacokinetic profile.

In short, Yes the way TRT and TOT is often done today.

For example, watch out for @Andrewgen_Receptors blood work when he finally posts that up.


You can be in the highest quartile of testosterone and not have the genes necessary for muscle building. A lot of guys go on TRT and expect the ability to build loads of muscle, some are disappointed.


Aka did not get everything else in order first before TRT…

Diet, training, bodyfat level.

What typical person does not have genes necessary for muscle building? Are you referring to someone with genetic disorder?

The topic was building muscle +/- TRT not being Phil Heath.


Isn’t this a huge assumption?

Why would properly measured 1,000ng/dL natural be his peak testosterone? Would the mean be a better representation? (Assuming normal distribution over time)

Exogenous testosterone is known to have a natural decay characteristic, so measuring at the trough is best for controlling the minimum. But what about the peak?

Do we know how endogenous testosterone varies? What are the cycle times? What does the distribution look like during a cycle of natural testosterone release? What is the peak? Low? Mean? Standard deviation?

In other words, let’s make the comparison as close to apples-to-apples as possible.


Go look over the thread I shared above on diurnal variation for endogenous T production. You gotta do a little work if you want to educate yourself. I put it all there for you; you just have to click and read.

Your comment does bring up a good point on old vs old men and their endogenous peak to trough ratio. Typically much less variation in older guys. TT tested in early morning as that is where TT peaks in human male.


For injectable T Cypionate I provided you a reasonable estimate for various injection frequencies. See Table.

Peak/mean/trough ratios and you can convert between.

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I agree we should but that is not how the data is measured and presented so difficult for the laymen to make the apples to apples comparison.

I agree for same mean TT/fT with or without TRT then anabolic potential should be closer to parity. Intent above was to daylight how 1000 on TRT can be very different than 1000 natural with respect to mean TT (given the way measurements are typically done)


Let’s discuss this assumption first!

Why assign natural with a 1,000 peak, and not also with the TRT person?

  1. Give them both the same peak and compare the means and areas.
  2. Give them the same means and compare areas

Nonetheless, as I understood the OP question. He was considering twins with the only variable being one was relying on his own testosterone and the other was using exogenous testosterone. The only way this question makes any scientific sense is if the twins were accessing the same amount of testosterone.


I see our different approaches.

Let me express the method I approach problems. First I check all assumptions. I require them to be as close to unquestionable as possible.

I had a good work friend who was one of the most logical people I worked. He could logically prove most anything he wanted. His flaw, which almost no one saw, was that in his argument there was at least one faulty premise. He and I argued tooth and nail. His logic was flawless, yet his premises might not be.

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You could. But would take the treatment above to do the conversions. Hence why I provided them.

Case 1 (see data above)
Case 2 (same mean so same area under curve since mean = area under curve ÷ delta time)

Good points. I made assumption that numbers above were provided from most realistic (probable) practical scenario. Good place to start.

For natural: endocrinologist/PCP followed medical society guidelines and measured early morning TT at peak

For TRT: doc pulled patient’s blood work right before next injection.

Guys many times don’t understand that the number they see on the piece of paper could be very far off from their mean. So I like to raise awareness. We would have fun together at work.


Assuming both twins have identical accessible testosterone, IMO there would be no difference in body composition and exercise performance.

On the down side the TRT has disrupted his natural production of testosterone and has needlessly complicated his life. (I know this is not what you intended with the thread)


Yes all this was my selfish (?) / altruistic (?) / sadistic (?) public service announcement for pharmacokinetics, math, stats and all the other stuff most don’t care for until they need an answer.

“Just give me a shot Doc; spare me the details.” :grinning:


Not every man has the ability to look like the Dwayne Johnson, there will be a lot of guys who have high expectations that might not be inline with what they can achieve.

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Both are correct, but comparison serves no value.

Anyone without a genetic disorder can build muscle.

Very few, and I do mean very few, can gain as muscle as they wish. (Note: I acknowledge many say they don’t want as much muscle as is demanded to be on the Olympia stage. I don’t include myself in that group.)

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Yes. Trt twin has an advantage. Natural twin can be stressed, not sleep well, etc and his levels will dip.

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Now I like that. Taking TRT as an insurance policy of what “might” happen. “Doc, I might get stressed out, and could get poor sleep, and all that could lower my testosterone. Don’t I qualify for TRT?”


At pinpointed instant of time … no. As others have stated natural t levels will fluctuate a great deal versus controlled TRT. That aside… no. And @systemlord is correct that some just don’t have the genes for it. For example my biceps lack but my shoulders and triceps ar large. I have poor outter pec insertions but great inner. Point being some guys have poor all around genetics for muscle building and not just weak points.


Wow… didnt expect so much reply’s. Thank you all for valuable inpunt which, clearly, you guys took the time for!

English isnt my first language, so i’m doing my best to really understand some of the more complex responses.

From what i could understand (in very short) is that the TRT twin would have an advantage? Mainly because more ‘higher’ and stable elevated Testosterone levels and considerable more free testosterone.