The secret to younger-looking skin may be a fungal toxin called cytochalasin B. As we age, our skin cells become rigid and grow larger. Researchers led by Tufts University’s Igor Sokolov previously reported that cytochalasin B can restore elasticity to skin cells. Now, his team has shown that the toxin can shrink skin cells too (PLOS One 2015, DOI: 10.1371/journal.pone.0122774). Sokolov and coworkers applied a cream containing cytochalasin B to mice and found that it reduced the size of their skin cells by around 50%. The mice had smoother skin compared with mice that were treated with plain cream. Although cytochalasin B is a toxin, the compound appeared to have no ill effects on the mice, and there were no changes beneath their skin. The researchers also applied the compound to cultured human skin cells. Older skin cells shrunk 20–40% in response to the compound, whereas younger skin cells didn’t shrink significantly. Sokolov hopes to test the cytochalasin B cream on humans soon. In addition to imparting younger-looking skin, he notes, cytochalasin B could help scientists better understand the cellular aging process.