Cosmetic surgery to the lips could be one of the most effective ways to reduce a woman's perceived age, new research has suggested.
According to a study funded by Unilever, women with full, plump lips are generally thought to be younger than their true age.
The research, funded by Unilever, looked at more than 250 women of all ages and included twins.
David Gunn, who led the study, said: "When we identified people who looked young for their age, we were struck by the difference in their lips.
"It is a feature that is strongly genetically determined and relatively easy to measure."
As the thickness of lips is generally decided by genetics, many women turn to plastic surgery, such as collagen or silicone implants in order to plump up their smile.
Botox™ is another option, although Mr Gunn advised that thin-lipped middle-aged or elderly women would benefit little from plastic surgery to the lips as it "doesn't counter the impact of a wrinkled face".