Acne often resolves spontaneously after the late 20s for several reasons.
"While there is generally spontaneous regression after age 20 in the vast majority of boys, girls may continue to experience acne during adult life."
Ramos-e-Silva, Marcia, and Sueli Coelho Carneiro. “Acne vulgaris: review and guidelines.” Dermatology nursing vol. 21,2 (2009): 63-8; quiz 69.
"The most agreeable feature of acne vulgaris is its spontaneous involution after adolescence in most patients. This phenomenon is unexplained. It cannot be attributed to a decrease in sebum production, since sebum output remains steady in adult life whether one has or has not had acne. Numerous explanations have been proposed, but they are all speculative." (Plewig & Kligman, 1993).
Common theories:
1. Hormonal Adjustments: Hormonal changes that stabilize after adolescence can lead to a decrease in acne. Hormonal fluctuations are a major cause of sebum production, which contributes to acne. As hormone levels stabilize in adulthood, sebum production may decrease, reducing acne occurrence
3. Natural Skin Changes: With aging, there are natural changes in skin texture and oil production. The pilosebaceous units may undergo changes that reduce the severity or frequency of acne outbreaks
3. Cellular Mechanisms: Some studies suggest that the remission of acne lesions may involve cellular changes like de-differentiation of sebocytes which leads to reduced sebum secretion specifically in the affected pilosebaceous units (Downie, Sanders, & Kealey, 2002).(edited)
