Steve Horvath is a professor of human genetics and biostatistics at the University of California, Los Angeles. Horvath had a lifelong interest in solving an important problem in aging research: how do we measure aging? In 2011 Horvath and his collaborators at UCLA described the first age estimation method (epigenetic clock) for saliva based on chemical modifications of the DNA molecule known as DNA methylation. Two years later Horvath published an age estimator that applies to all tissues and cells of the human body. This discovery, known as the Horvath epigenetic clock, was unexpected because cells differ greatly in terms of their epigenetic patterns. Recently, he has studied treatments that slow or even reverse aging in humans. He and his colleagues have demonstrated that the epigenetic clock predicts lifespan and is related to centenarian status, obesity, HIV infection, early menopause, progeria, and many other age related conditions. Steve Horvath is a professor of human genetics and biostatistics at the University of California, Los Angeles. Horvath had a lifelong interest in solving an important problem in aging research: how do we measure aging? In 2011 Horvath and his collaborators at UCLA described the first age estimation method (epigenetic clock) for saliva based on chemical modifications of the DNA molecule known as DNA methylation. Two years later Horvath published an age estimator that applies to all tissues and cells of the human body. This discovery, known as the Horvath epigenetic clock, was unexpected because cells differ greatly in terms of their epigenetic patterns. Recently, he has studied treatments that slow or even reverse aging in humans. He and his colleagues have demonstrated that the epigenetic clock predicts lifespan and is related to centenarian status, obesity, HIV infection, early menopause, progeria, and many other age related conditions. This talk was given at a TEDx event using the TED conference format but independently organized by a local community. Learn more at https://www.ted.com/tedx