There is no upper limit worth mentioning. The lower limit is not about age but about whether your loss has stabilised.
Pattern loss at 22 is usually still accelerating. Transplanting a low hairline before the pattern is clear produces an island of hair by 30. We often recommend medical therapy first and surgery at 25–27, once the trajectory is visible.
Loss patterns are established, donor supply is measurable and expectations are usually realistic. Most of our cases sit here, and outcomes are the most predictable.
Age itself is not a contraindication. What matters is general health, blood pressure control, medications such as blood thinners and realistic goals — a mature hairline rather than a reconstruction of 1985.
Unstable alopecia areata, uncontrolled diabetes, active scalp infection and unrealistic expectations. None of them are about the calendar.
No. Finasteride slows further loss at any age; it simply cannot recover what is already gone.