What men really think about lip filler... and the 'perfect' size

Men tend to find women with natural lips more attractive, while women are drawn to plumper pouts, new research found.

A research team at the University of Sydney recruited 32 students – 16 male and 16 female – and showed them a series of computer-generated images of human faces with varying lip sizes.

Each face was shown with seven different lip sizes, and all of the participants in the study rated each face several times. In total, they evaluated 168 face images.

The researchers then averaged the ratings to identify patterns in preferences. People generally preferred slightly plumper lips on female faces and slightly thinner lips on male ones. Both men and women preferred male faces with thinner lips.

But when they looked more closely at preferences of the genders, researchers identified another pattern.

Men consistently rated female faces with natural-sized lips as the most attractive - think Emma Watson or Natalie Portman — while women preferred plumper lips on female faces - think Kylie Jenner or Angelina Jolie.

‘In other words,’ the researchers concluded, ‘Our data suggest that costly cosmetic procedures that increase female lip size, such as injectables and lip-enhancing surgeries, may not appeal to men.'

In the study, researchers started with images of 24 different faces, half male and half female, giving neutral expressions.

While the original versions of the images showed natural-sized lips, three versions had bigger lips and three had smaller lips, creating 168 images.

In 350 milliseconds, each participant looked at a face and rated its attractiveness based on lip sizes, from small to cartoonishly large, without getting too much time to focus on individual features. They rated each face five times in random order.

Female faces were rated most attractive with slightly plumper lips, while male faces were preferred with thinner lips.

In the second part of the experiment, researchers showed each study participant three faces with either moderately larger or smaller lips for 15 seconds.

Then, they were shown all seven lip sizes and rated the attractiveness of the faces again.

The results showed that men participating in the study preferred thinner lips on male faces, while female participants preferred plumper lips on female faces.

The findings indicate that gender may influence attractiveness preferences, with participants tending to rate faces of their own gender more favorably, especially when it comes to lip size.

They were published in the journal Proceedings of the Royal Society B: Biological Sciences.

Many women spend thousands of dollars every year on injectable lip fillers, typically using hyaluronic acid.

Beauty trends borne out of social media have boosted their popularity culminating in plump lips becoming the standard of female beauty.

The visual culture dominated by TikTok and Instagram can create pressure for people, women especially, to conform to this standard, even when it is artificially created through cosmetic procedures.

Over time, as people see these enhanced features repeatedly, they may come to accept them as the norm and aspire to achieve them themselves.

Fillers are particularly popular among young adults.

A 2023 report by the American Academy of Facial Plastic and Reconstructive Surgery found that nearly 75 percent of plastic surgeons surveyed said they are seeing more people under 30 request injectables, including lip fillers.

Beginning to undergo fillers can be a slippery slope, the Australian researchers warned.

Exposure to artificially enlarged lips, beyond natural limits, could trigger a feedback loop where the observer only finds progressively plumper lips attractive.

‘Ultimately, such a process would culminate in lip dysmorphia,’ they said.

The term refers to when a person’s perception of their lips (or any feature) becomes distorted, and they feel compelled to alter them repeatedly, even if there is no actual flaw.

What people find attractive can change over time due to repeated exposure to altered features like overly puffed lips, meaning their perceptions of attractiveness can adapt and shift.

They added: ‘It follows that, in the real world, when people are seeking to permanently modify their appearance with surgery… over time, they will visually adapt to the new shape or size of their modified features, and this will likely normalize their definition of attractiveness and motivate further surgery.’