My friend Dana is a great storyteller. I think it has to do with her eyebrows. They raise as she rehashes Bumble dates, furrow as she recalls interoffice drama.

I say all this because Dana, though 26, has a visible wrinkle across her forehead, and her expressiveness—while endearing—is likely the cause. “There are two types of wrinkles: Static and dynamic,” says Dr. David Shafer, a double board-certified plastic surgeon in New York City. “A dynamic wrinkle is caused by the muscle underneath the skin squeezing, like when you raise your eyebrows. If that happens repeatedly, a dynamic wrinkle eventually becomes a static, lasting wrinkle.”

According to Dr. Shafer, it’s in these sorts of cases—where repeated action has caused the wrinkle—that Botox can work preventatively, since it temporarily stops the muscle from contracting. And if a dynamic wrinkle is caught early on, Botox can even prevent the deeper static wrinkle from forming entirely. Yes, really.

In terms of when to start treatment, Dr. Shafer says there’s “no age requirement” but is quick add that Botox is only FDA-approved to be administered to those over age 18. Instead of using age as a gauge, “when there’s a symptom, you treat it,” he says.

As for Dana, she took the plunge and got Botox to combat that pesky wrinkle in both the short- and long-term. (But before she did, her wise beauty editor pal—ahem, me—advised her to check out what the “after” might look like via Botox’s Treatment Visualizer app.) Turns out preventative Botox really is a thing.

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