Treating obese mice with the cytokine known as TSLP led to significant abdominal fat and weight loss compared to controls, according to new research published Thursday in Science from researchers in the Perelman School of Medicine at the University of Pennsylvania. Unexpectedly, the fat loss was not associated with decreased food intake or faster metabolism. Instead, the researchers discovered that TSLP stimulated the immune system to release lipids through the skin’s oil-producing sebaceous glands.