It sounds counterintuitive — Botox paralyzes the muscles under the skin, doesn’t it? So how can it make the skin more stretchy?
A new study suggests something else may be going on. The researchers in Canada show that the injections make the skin more elastic, and that the effect lasts for about as long as the compound stays in the body.
They’re not quite sure what’s going on. But other cosmetic treatments have been shown to stimulate skin cells called fibroblasts, which respond by making more collagen and elastin. That may be what’s going on with Botox, said Dr. James Bonaparte of the University of Ottawa and Dr. David Ellis of the University of Toronto.
"The changes occurring in patients' skin appear to be the opposite of those associated with the aging process and UV radiation exposure and inflammation. This study also suggests that the duration of effect of these changes mimics the duration of effect of the medication,” they write in the Journal of the American Medical Association’s Facial and Plastic Surgery publication.
People who get repeated shots of Botox seem to have permanent effects after a while. It may be that they “learn” not to frown and make other expressions that lead to wrinkles. It might be the muscle changes.
But it’s also possible that the Botox itself changes the skin.
"We know that we can weaken the muscle," says Dr. Catherine Winslow of the Indiana University School of Medicine, who was not involved in the study.
"What we don't know is why patients who get Botox seem to get nicer-looking skin that patients who don't," added Winslow, who wrote a commentary on the study.
Ellis and Bonaparte studied all first-time patients with moderate wrinkles who showed up at the Toronto clinic from October 2012 to June 2013 for Botox injections around and between the eyes. That’s a lot- the clinic does up to 1,200 Botox injections a year.
They used a device called a Cutometer to measure skin elasticity before and after the injections. All cosmetics were removed. They also tested each patient’s arm as a control.
In the end, 43 women with an average age of 55 took part. They got injections around and between their eyes. Measurements showed that skin became more elastic, but lost this extra stretchiness after 4 months.
“After two to three months, these changes begin to wear off and skin begins to return to its normal characteristics for that individual,” the pair wrote.
More study is needed to find out just what the Botox is doing. Botox, which is short for Botulinim toxin, is made from a paralyzing agent produced by the Clostridium botulinum bacteria.
The toxin injections might make the collagen in the skin “more organized”, the researchers said. Other studies have shown Botox can cause the skin to produce more collagen and elastin, which makes the skin more elastic.
“These changes mimic those that one would expect if a change to more youthful skin, as measured by the Cutometer, were to occur,” they wrote.
It's also possible that freezing the muscle stops it from producing other toxic waste products, says Winslow. "If we can weaken the muscles, we don't get those waste products," she said. It might be that Botox is an anti-aging and anti-oxidant, she said.
Making the skin produce more collagen and elastin is a major goal for dermatologists and plastic surgeons. Over time, the skin produces less and less of both. As skin ages, elasticity falls from an average of 70 percent at 20 to 50 percent at age 70.
Rubbing in these products in creams or serums does not work to add collagen or elastin to the skin. It has to be produced internally.
But mechanically stimulating the skin does sometime cause production to resume. Other researchers have found that repeated injections of skin fillers such as Restylane and Juvederm can sometimes stimulate the fibroblasts. So can some of the many treatments that fall under the general area of radiofrequency skin tightening.
Ellis and Bonaparte say it is remotely possible that the Botox inflames the skin, causing it to distend. But usually, the opposite happens in real inflammation, and they don’t think that’s what is happening.
There are medical uses, Winslow notes. Botox can help scars heal better and for patients with scarring it can be important to find ways to improve the skin's elasticity. And of course the cosmetic effects attract many people.
"It's temporary," she said. "But it's fun."