How big of a role do genetics play?

Something I’ve been thinking a lot about recently is the role that genetics play when it comes to fitness, response to exercise, and also response to androgenic stimulus.

One easy citable example of how genetics impact our physiology is response that is typical of folks of South American origin who are very susceptible to have their bodies react to sugars, especially processed sugar. It’s not been a great part of their diet until very recently (in bio/evolutionary terms). However, even that impact seems to be individualized in response.

I was thinking about this topic specifically with regards to response to TRT and other androgenic stimuli. Personally, I seem to respond very strongly to my TRT protocol while staying within sensible ranges (900-1100 Total Test). It’s not clear to me how much of my response is due to the fact I had been living with very low (sub-200) levels through natural production, my training work ethic, diet, or a genetic response mechanism. I am curious if there’s ever been any studies to see how response differed from androgenic stimuli across different men with other conditions kept the same.

It’s funny that when pro bodybuilders talk about their own rise, they often cite genetics as a key driver to their success. I’ve never been able to differentiate whether they mean genetics that enable that amount of muscle to look good on their frame (for an example of someone to whom heavy muscle does not naturally sit on frame, see Sam Sulek), or whether they are referring to their own genetic response mechanisms to the various stimuli as being a key differentiator…. Maybe it’s both.

I guess what I’m really asking is opinions as to how markedly different responses are to TRT and other anabolic stimuli?

Of course, we all only have our own experiences to go off, but I feel that I have responded unusually strongly to TRT (before and after pic 15 months apart attached), though I was both a model candidate and I have kept a good diet and training ethic with heavy loads along the way. I have cut about 30lbs fat and added 30lb muscle in just over a year (for ref I’m 40y/o, 6’4, 255lb) . I am trying to figure out if I’m just lucky with genetics or whether my results are replicable by the masses with good work ethic and nutrition.

One of the greatest advantages to great genetics is that they get very rapid positive reinforcement for most any effort they take in the weight room. Success breeds more success. With consistent success they keep a very positive attitude.


Its a combination of truly needing TRT and genetics IMO. I also had a huge response in a short period, whereas friends of mine did not. Why? My FT was half the lowest range and went up 5x on TRT (still well in range). Thats a huge increase. My friends were low mid range and doubled their T levels. See the difference?

Two, some people respond to drugs better and others to training stimuli. If you get lucky enough to be a responder to both, damn you are going to get good results. At 6’4" you’re already a genetic outsider in the upper 90th percent of height. Count your blessings “asshole” :laughing:


Do you think there is merit to the idea that some people respond well to some AAS, but not others in regards to gains. For example, I’ve heard guys say they don’t respond to Test, but they blow up on Deca. I think it could be reasonable to think it is true, but it might also just be that they are responding better to stronger drugs, or that adding Deca is just raising the total of AAS they are blasting?

Maybe the limiting factor for gains is individual? For one guy it might be nitrogen retention, for another it could be nutrition partitioning, for another it could be GH / IGF-1 production (seems reasonable based on how much variation there is in reported benefits from HGH), other factors not listed…

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