In people who already train with weights, doing lateral raises with dumbbells or cables for 8 weeks results in a 3.3% to 4.6% increase in the size of the side shoulder muscle.

We analyzed the available evidence and found that lateral raises with dumbbells or cables are associated with small increases in the thickness of the side shoulder muscle in people who already train with weights. What we’ve found so far is based on two assertions, both of which support this observation, with no studies contradicting it [1][2]. In individuals with resistance training experience, performing lateral raises for eight weeks led to a 3.3% to 4.6% increase in the size of the lateral deltoid muscle, regardless of whether the exercise was done with dumbbells or cables [1]. This same range of change was seen when the exercise was performed twice per week over the same eight-week period [2]. Both assertions come from the same pool of data, with 60 support points each, but neither includes details about sample size, measurement method, or control conditions. We cannot say whether this change is large or small in practical terms, nor can we determine if other exercises might produce similar results. The evidence we’ve reviewed does not explain how long the gains last after stopping the exercise, or whether they continue to grow beyond eight weeks. There is also no information on how these changes compare to other shoulder exercises or whether they translate to improved strength or appearance. What we’ve found so far suggests that for people already lifting weights, adding lateral raises with dumbbells or cables may contribute to a modest increase in side shoulder muscle thickness over two months. If you’re looking to build out your shoulders and already train regularly, including these movements twice a week could be a simple way to target that area.