According to Dr. Lehavit Akerman, dermatologist and chair of the Israeli Society for Dermatologic Surgery, the change in odor isn't random."There isn't one definitive scientific explanation, but we do know that body odor changes with age -- and you can smell it," she explains. "Just as puberty brings a hormonal explosion that affects body scent, aging also brings its own shift. The body undergoes cellular aging -- cells known as 'zombie cells' that can no longer repair themselves begin to poison their surroundings."