The wrinkle results are in and might surprise some people. The anti-wrinkle injection Dysport proved better at reducing crow's feet than its older, more popular competition, Botox.

So says a first-of-its-kind study, published in the Archives of Facial Plastic Surgery, which compared the two different kinds of botulinum toxins. In a 30-day trial, researchers injected 90 study participants with both medications, using one kind on the right side of the face and the other on the left. They found that both physicians and patients rated Dysport as more effective at reducing crow's feet lines, while smiling, than Botox.

When the facial muscles were at rest, researchers noted no significant differences between the two agents.

"In this study, we were injecting the two agents in the same person's face," said Dr. Cory Maas, a San Francisco-based facial plastic surgeon and lead author of the study. "The sites were far enough away from each other so that the agents could not have an effect on each other, and by doing a split-face study, we have taken all the variables out of the equation, like age, gender and ethnicity."