Skeletal muscle has proved to be very difficult to grow in patients with muscular dystrophy and other disorders that degrade and weaken muscle. Researchers now report boosting muscle mass and reversing disease in a mouse model of Duchenne muscular dystrophy, using a “cocktail” of three compounds identified through a new rapid culture system. Adding the same compounds to stem cells derived from patients’ skin cells, they then successfully grew human muscle cells in a dish.