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.
Evidence from Studies
Supporting (5)
Community contributions welcome
Neither load nor systemic hormones determine resistance training-mediated hypertrophy or strength gains in resistance-trained young men
Even though some people think lifting heavy weights makes your muscles grow because it boosts certain hormones, this study shows that whether you lift light or heavy weights — as long as you push until you can't do more — your muscles grow the same amount, and the hormone spike doesn’t matter.
Even though exercise makes hormones like testosterone rise in the blood, this study found that those spikes don’t actually determine whether muscles grow bigger — what matters more is how sensitive the muscle itself is to hormones.
The effects of supraphysiologic doses of testosterone on muscle size and strength in normal men.
This study gave men extra testosterone pills and found their muscles grew bigger—even without working out. That means you don’t need your body to naturally spike hormones after exercise to build muscle; just having more testosterone around is enough.
Elevations in ostensibly anabolic hormones with resistance exercise enhance neither training-induced muscle hypertrophy nor strength of the elbow flexors.
People who lifted weights with and without a big hormone surge ended up with the same muscle growth — so the hormone spike isn’t needed to get bigger muscles.
Muscular and Systemic Correlates of Resistance Training-Induced Muscle Hypertrophy
The study found that even when people didn’t have big spikes in muscle-building hormones after working out, their muscles still grew — so those hormone spikes aren’t needed for muscles to get bigger.
Contradicting (0)
Community contributions welcome
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.