We don't currently have enough proof to say whether working out a specific muscle group three times a week builds more muscle than doing it twice a week. Because the research isn't clear on this, experts can't yet recommend training muscles more than twice weekly for growth.

Our current analysis shows that we do not have enough proof to determine whether training a muscle group three times a week builds more muscle than training it twice a week. The evidence we have reviewed leans toward the idea that the research is not yet clear on how often you should train a muscle. We found 38 studies support, 0 studies refute this question [1]. What we have found so far is that the available data does not give us a clear answer. Because the research is not definitive, we cannot yet recommend training muscles more than twice a week specifically for growth. Our analysis is based on the studies we have reviewed up to this point, and we know this view will improve as more research becomes available. We stick to reporting what the numbers show rather than making broad claims. The evidence we have reviewed suggests that how often you train a muscle may not be the deciding factor for growth right now. Not enough evidence to say which schedule is better. If you are trying to build muscle, you can stick to a schedule that fits your recovery and lifestyle. Training a muscle group twice a week remains a practical starting point while we wait for clearer data. We will keep tracking new studies and update our findings as they come in.