German researchers claim that facial expressions have an impact on how old we look and smiling can actually make one look younger.

Experts cited the following reasons for this observation- firstly, it is hard to tell whether the facial wrinkles seen in a smiling face are the effect of the smile or permanent. Secondly, we consider smiling faces more attractive in other ways including being younger than they actually are.
The study has been published in the journal Psychology and Aging.
Source-Medindia