Different experts look at the research and say the reps needed for muscle growth could be anywhere from 3 to 40, but I think 6 to 35 is the best estimate.

The study compared different rep ranges (low, moderate, and high loads) when people train until they can't do more reps. It found that muscle growth was the same no matter how many reps they did, which means doing anywhere from about 8 to 15+ reps works equally well for building muscle - supporting the claim that 6-35 reps can all be effective.

This big review of many studies found that whether you do many reps with light weight or few reps with heavy weight, you get the same muscle growth - as long as total work is equal.