A study of 1,000 people in 35 countries revealed that the perfect lip shape is all down to symmetry. More than 60% of respondents thought a 1:1 ratio between the upper and lower lip was the most attractive shape. A cosmetic surgeon in London said a heavily-defined cupid's bow is the most-requested lip feature.

What is the rarest shape of lips?

Cupid is the rarest of all lip forms. Cupid has a powerful, youthful appearance, and is very prominent in pre-adolescent females. Due to the natural growth process in a female's lips, the fullness of the lips fill in the middle first, then the sides.

Are wide lips attractive?

"A woman who has large lips, suggesting a strong mating potential, with average length and width ratios will always be more attractive than a woman with narrow lips and average length and width ratios," wrote the researchers.