Why some guys grow bigger muscles than others
Muscle Androgen Receptor Content but Not Systemic Hormones Is Associated With Resistance Training-Induced Skeletal Muscle Hypertrophy in Healthy, Young Men
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Even if two guys lift the same weights, one might grow more muscle — this study found it’s not because of their hormone levels in blood, but because of how many hormone sensors they already had in their muscles before starting.
Surprising Findings
Intramuscular testosterone and DHT levels were identical between high and low responders — despite the high responders gaining 2–3x more muscle.
Common belief: More local hormone = more growth. This study proves the opposite — muscle growth isn't driven by how much hormone is inside the muscle, but by how well the muscle can detect it.
Practical Takeaways
Stop chasing 'testosterone-boosting' supplements or post-workout hormone hacks — focus on consistent training, protein intake, and recovery instead.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Even if two guys lift the same weights, one might grow more muscle — this study found it’s not because of their hormone levels in blood, but because of how many hormone sensors they already had in their muscles before starting.
Surprising Findings
Intramuscular testosterone and DHT levels were identical between high and low responders — despite the high responders gaining 2–3x more muscle.
Common belief: More local hormone = more growth. This study proves the opposite — muscle growth isn't driven by how much hormone is inside the muscle, but by how well the muscle can detect it.
Practical Takeaways
Stop chasing 'testosterone-boosting' supplements or post-workout hormone hacks — focus on consistent training, protein intake, and recovery instead.
Publication
Journal
Frontiers in Physiology
Year
2018
Authors
Robert W Morton, Koji Sato, M. Gallaugher, Sara Y Oikawa, P. McNicholas, S. Fujita, Stuart M Phillips
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Claims (6)
If you're a young, fit guy who lifts weights, having more androgen receptors in your muscles might mean you gain more muscle size and strength after 12 weeks of training compared to others.
Even if your testosterone, growth hormone, or IGF-1 levels spike right after a workout, you don’t need those spikes to grow muscle — your muscles can still get bigger without them.
Even if your body has more of these muscle-building hormones like testosterone and IGF-1, it doesn’t mean you’ll grow bigger muscles from lifting weights over 12 weeks.
When some guys get much bigger from weight training and others don’t, it’s not because the big responders have more of these male hormones inside their muscles — both groups have about the same levels, so something else must be causing the difference.
When some people lift weights, their bodies make more of a certain enzyme—but only if they’re the type who gains muscle easily. People who don’t gain much muscle don’t see this enzyme change. And even when the enzyme goes up, it doesn’t match up with how much muscle they gain, so it probably doesn’t cause the muscle growth—it just happens along with it.