Botox, long mocked for simply hiding wrinkles by partially paralyzing the face, may actually make skin more elastic and more resistant to wrinkles.

Botox, an injection that paralyzes facial muscles to reduce the appearance of wrinkles, has a reputation for being the remedy of choice for vain starlets because it’s superficial and fleeting.

But a recent study suggests it may not be quite as superficial or as temporary.

The drug increases skin elasticity for the three to four months that it stays active, according to a Canadian study published in JAMA Facial Plastic Surgery by dermatologist Dr. James Bonaparte of the University of Ottawa and Dr. David Ellis of the University of Toronto.

“The initial theory for Botox was you paralyze the muscle, you then can’t make the wrinkle anymore because you can’t move. This is suggesting that there’s maybe more going on than just that, that you’re actually remodeling the skin to get rid of the wrinkle,” Bonaparte said.

Dermatologists had observed that even deep wrinkles that weren’t erased by Botox became less severe while it was active. Bonaparte has endeavored to measure the effect scientifically.

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In the current study, he and Ellis used a Cutometer, a device that sucks the skin and measures how much it rebounds to its previous position. As we age, our skin becomes less elastic, recoiling about 30 percent less at age 70 than it does at age 20.

Flaccid skin makes us look older. It also makes the skin more prone to wrinkle.

The researchers found that when the effects of Botox were at their most powerful, the drug could increase elasticity by 30 percent. The effect peaked at two months and then waned before dropping off at four months.

The researchers tracked 43 women who were using Botox for the first time.

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Bonaparte’s earlier work on the same topic was met with criticism. Critics argued that what seemed to be elasticity could simply be swelling as a result of the injury from injection. As the skin heals from injury it draws in more water and becomes more elastic for a week or two.

The current study ruled that out by showing that injury resulted in a different pattern of resistance to the suction.

“Botox might be doing two things, one to the muscle one to the skin,” Bonaparte said.

If indeed Botox makes the skin more elastic, it may also help prevent the formation of wrinkles. That could expand the market for cosmetic injections significantly. More than 6.6 million Americans underwent treatment with Botox or a similar drug last year, according to the American Society of Plastic Surgeons.

Bonaparte, who also works in private practice, performs Botox injections for a fee. His study was funded by Allergan, the pharmaceutical company that makes Botox. All of the research to date on the potential anti-aging effects of Botox has been funded by Allergan, Bonaparte said.

Two other products, Dysport and Xeomin, can also legally be used to mute the furrow between eyebrows. Like Botox, they are derived from the naturally occurring botulinum toxin. Only Botox has the approval of the Food and Drug Administration for use on crow’s feet, but the others are often used off-label.

“There’s not reason to believe the other drugs wouldn’t have the same effect,” Bonaparte said.

To nail down exactly how the botulinum toxins ramp up elasticity, the next step will be to remove small bits of skin from participants before and after the procedures.

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