Have you ever wondered why and how people age differently? Going to a class reunion often sparks these thoughts. Some people look like no time has passed, while others looked like a century has passed. A study conducted by Stanford University scientists was published in Nature Medicine, revealing possible explanations for how people age differently. In addition to that, it also raises the possibility of how we can impact the personal aging process through lifestyle changes and targeted medication. Comprising of 43 healthy adults, the study analyzed blood and other biological samples that would reveal molecular changes over a two-year period. It revealed that people do age at different rates, as well as in different ways. These pathways have been categorized by “ageotypes:” kidney, liver, immune and metabolic.