Harvard scientist David Sinclair reveals breakthrough human trials using gene therapy to reverse aging. His lab's OSK gene therapy restores vision in glaucoma patients and reverses cellular aging in mice by 75%, potentially opening the door to treating age-related diseases like Alzheimer's and arthritis through epigenetic reprogramming. Three genes called OSK can safely reprogram cells to behave like younger versions by reinstalling their youthful epigenetic instructions without causing cancer or stem cell transformation. A drink and pill cocktail tested in mice restored physical fitness, memory, and strength within four weeks, suggesting oral longevity treatments may extend human lifespan by 15+ years without major lifestyle changes. The biological clock of aging is controlled by chemical markers called methyls on DNA; reversing these markers restores vision, regrows damaged nerves, and may cure currently incurable age-related diseases. Five evidence-based longevity factors—avoiding smoking and excess drinking, sufficient sleep, exercise, and reliable relationships—can reliably add 15 years to human life expectancy.