If you lift light or heavy weights but do the same total amount of work, your muscles grow about the same amount—whether you're using light dumbbells or heavy barbells.

If you lift light or heavy weights but do the same total amount of work, your muscles grow about the same amount—so lifting light weights can be just as good for building muscle as lifting heavy ones.

If you lift light weights for more reps or heavy weights for fewer reps—but do the same total amount of work—you’ll grow your muscles just as much either way.

The total amount of work done (weight × reps × sets) seems to matter for muscle growth — more work generally leads to more muscle, even if the weights are light.

When people lift weights regularly, their muscles usually get about 5% bigger on average, no matter what kind of weight routine they follow.

Lifting heavy weights might help you build slightly more muscle than lifting light weights if you're new to training, but the difference isn't big enough to say for sure it's real.