A few weeks ago, I wrote about what Botox is and how it works. What I didn’t get around to talking about in that post, however, is how long it works for—and since that’s usually one of the first questions I get from patients who are interested in getting a Botox treatment, I thought I would explain that in this week’s post.

The short answer is that Botox can last for between 3-6 months, but generally it lasts closer to 3-4 months. The longer answer is that a number of factors determine how long Botox will last in each individual, which is why it’s necessary to offer up a range of months rather than one specific number.

Factors that can affect how long Botox continues to work include: how it is mixed (how many units are used); your unique physiology (how deep your wrinkles/how strong your facial muscles are, and how your body reacts to the injections); how many times you’ve had Botox consistently injected into the same area (long-term application can make it last longer); and how and where the Botox is injected.

Because everyone is different, it’s impossible to say exactly how long Botox will work for any given person—but a board-certified plastic surgeon with experience injecting Botox should be able to give you a better idea of how long it will last for you if you make an appointment and give them a chance to examine the area in person. Ultimately, though, you won’t know exactly how long your Botox injection will last until you try it for the first time. Luckily, the effects don’t disappear overnight; they wear off gradually, and muscle movement slowly returns. So don’t worry—you’ll know when it’s time for your next treatment before the wrinkles come back!