Botox injections make wrinkles look better for the first few years, but after 15 years, everyone’s wrinkles look about the same no matter how often or how young they started getting injections.

The study used computer models to simulate what happens when people get Botox shots every 6 or 8 months for 15 years. It found that Botox smooths wrinkles at first, but after 5 years, everyone’s wrinkles come back to about the same depth — no matter when they started or how often they got shots.