Since the advent of lipstick in ancient Mesopotamia 5,000 years ago, plush red lips have dominated conversations and grabbed men's attention.

While ingredients have transitioned from crushed insects to wax and oil, a recent study found that those macaroon-red shades make women look younger by creating strong contrasts against the rest of the facial features and skin tone, The Daily Mail reported.

The joint study with psychologists at Gettysburg College in Pennsylvania and Chanel's R&D division published in PLOS ONE journal could explain why Mightiest Maraschino from Clinique or Dolce & Gabbana's Attractive Monica shades can unconsciously alter age perceptions and is being applied to stoke those lips.

The scientists took face images of French Caucasian women in one study between 20 and 69 years old and discovered that aging makes lips, eyes and eyebrows become paler as the skin becomes darker. 

The stark contrast between skin and features makes a woman look younger compared to less contrast seen in older women.

"For example, we found that the redness of the lips decreases with ageing, but the skin that surrounds the lips actually becomes more red, so the redness contrast between lips and the rest of the face decreases with age and that certainly is something that can be manipulated with make-up," Richard Russell, lead researcher and professor of psychology at Gettysburg, told BBC Radio 4's Material World.

Wearing lipstick is also commonly used to display teeth, according to another study in the United Kingdom.

Researchers confirmed their facial contrast study by digitally altering images of the women to make their features appear less or more pale. They found that viewers perceived the faces younger if women had stronger contrast between the features and skin tone.

"Unlike with wrinkles, none of us are consciously aware that we're using this cue, even though it stares us in the face every day," Russell added.