When people train a muscle group more frequently—increasing from 8 to 12 sets per week—they gain about 0.9% more muscle mass, according to a review of multiple studies.

We analyzed the available evidence and found that increasing weekly training volume from 8 to 12 sets per muscle group is associated with a small increase in muscle mass—about 0.9%—based on a review of multiple studies [1]. This finding comes from 48 studies or assertions that support this pattern, with none that contradict it. What we’ve found so far suggests that when people raise their weekly set count for a muscle group—from 8 to 12 sets—they tend to see slightly more muscle growth over time. This doesn’t mean everyone will gain the same amount, as individual factors like experience, diet, and recovery play a role. But across the studies we reviewed, the trend consistently pointed toward a modest benefit from adding those extra sets. We don’t know if this gain is meaningful for every person, or if it continues to rise beyond 12 sets, because the evidence we’ve reviewed doesn’t go further. There’s also no information here about whether this increase comes with higher risk of fatigue or injury. The evidence we’ve reviewed leans toward the idea that more volume—within this range—can lead to a bit more muscle growth. But we can’t say if this is the best approach for everyone, or if the gains are worth the extra time and effort. If you’re already doing 8 sets per muscle group per week and want to try pushing a little harder, adding 4 more sets might help you grow a little more. But listen to your body—more isn’t always better if it leaves you drained or sore for days.