Creatine, the organic acid that is popularly taken as a supplement by athletes and bodybuilders, supercharges a critical class of immune cells that activate and prepare the body’s key cancer-fighters, according to new UCLA research.

The study, conducted in mouse models and human cells and published in iScience, builds directly on earlier work from the same lab showing that creatine powers killer T cells in their battle against tumors. Now, the team has discovered that creatine also fuels dendritic cells, specialized immune cells that capture tumor fragments and direct killer T cells to attack.

Most approved cancer immunotherapies work by targeting killer T cells directly, yet only about 20%–40% of patients respond to them. Bolstering the dendritic cells that train and activate T cells could potentially offer a way to bring the benefits of immunotherapy to more patients.