Weight-loss drugs lead to significant facial muscle loss New research has found that people who have weight-loss injections are likely to suffer from significant facial muscle depletion. 20 April 2026 Weight-loss jabs may come with a striking downside - muscle loss in the face. Mounjaro has a major impact on facial muscles A major new review has found that popular injections such as Mounjaro and Wegovy, can lead to significant muscle depletion alongside fat loss.