Potion of Longevity

Suspended in this amber liquid is a tiny heart that looks like it is beating. It vanishes when the bottle is opened. When you drink this potion your physical age is reduced by 1d6+6 years, to a minimum of 13 years old. Each time you subsequently drink a Potion of Longevity, there is a 10% cumulative chance that you instead age by 1d6+6 years.