Scientists combined 24 different studies and found that whether you lift heavy, medium, or light weights, your muscles grow about the same amount.

This study compared people doing resistance training to failure with light, medium, and heavy weights and found that muscle growth was similar no matter how heavy the weights were - all three approaches built muscle equally well.

This large review of many studies found that muscle growth doesn't depend on how heavy the weights are - as long as people train until they can't do more reps.