Will vitamin D supplements keep me younger?

In a 2025 randomized trial of about 1,000 people (ages 50 or older), followed for four years, those who took 2,000 international units of vitamin D₃ per day showed cellular signs that suggested they were aging more slowly compared with people who did not take the supplement. It’s unclear if this benefit would continue from taking daily pills longer than four years. Scientists do know that taking vitamin D₃ supplements is important for people with osteoporosis or with vitamin D deficiency (as determined by a blood test).