Study examines impact of lip size on facial attractiveness

Iveta Ramonaite, Dental Tribune International

Fri. 6. June 2025

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SYDNEY, Australia: Research shows that facial attractiveness can significantly influence social decisions, including those related to dating, recruitment and even legal judgments. Given that the underlying mechanisms of facial attractiveness are still not fully understood, a recent study has investigated whether changes in lip size affect how male and female faces are perceived. The findings revealed gender-specific biases in perceptions of lip attractiveness and underscored the potential influence of cosmetic procedures on prevailing beauty standards and the development of lip-related dysmorphia.

As interest in beauty and body image continues to grow, even the subtlest aspects of facial appearance are increasingly scrutinised. Facial procedures have advanced to meet a broad spectrum of expectations regarding desirable features, and therefore enhancing or altering one’s appearance through plastic surgery and cosmetic treatments has become increasingly accessible and affordable.

In the study, the researchers recruited 32 students—16 female and 16 male. The participants were shown digitally manipulated images of a human face with variations in lip size based on deviations from a standard norm. Overall, the participants were shown 168 faces representing seven lip sizes and were asked to rate the attractiveness of lips displayed in each image. To examine whether participants’ perception of attractiveness would shift based on prior exposure, they were first shown faces with either enlarged or reduced lips and then asked to rate subsequent images. The approach aimed to assess whether localised changes in facial features could influence perceptions of attractiveness.

Overall, the findings indicated that female faces were rated as more attractive when their lips were enlarged, whereas male faces were rated as more attractive with reduced lip size. Gender-specific preferences further revealed that women favoured fuller lips in female faces, whereas men preferred thinner lips in male faces. Based on these results, the researchers suggested that cosmetic procedures that enhance female lip size—such as injectables and surgeries—may align more closely with female aesthetic preferences than with those of men. In line with this finding, Dental Tribune International has previously reported on a study that showed that greater lip volume is not always more aesthetically pleasing.

Additionally, the researchers noted that exposure to a particular lip size led participants to adopt it as the new normative standard, demonstrating a shift in the perception of attractiveness owing to visual adaptation. The results also showed that, even when lips were presented without the surrounding facial context, exposure still altered attractiveness ratings. This suggests that the brain processes lip size as an individual feature rather than solely in relation to the entire face.

“Our research highlights the subjective nature of beauty and the powerful influence of social and cultural factors,” lead author Prof. David Alais from the School of Psychology at the University of Sydney commented in a press release. “As cosmetic procedures become more accessible, it’s crucial to understand how these interventions can shape our perceptions and potentially lead to unrealistic beauty standards,” he continued.

“Our research highlights the subjective nature of beauty”—Prof. David Alais, University of Sydney

Prof. Alais noted that, although social conditioning was not directly examined in this study, the findings point to a complex relationship between social conditioning and gender. “This study provides valuable insights into how people respond to facial features based on immediately prior as well as acculturated visual experience,” he said.

The authors recommended that further studies should investigate the long-term impact of cosmetic procedures on body image, as well as the potential role of visual adaptation in the development of body dysmorphia.

The study, titled “Distortions of lip size bias perceived facial attractiveness”, was published online on 9 April 2025 in Proceedings of the Royal Society B.