Exploring Beautiful Lips PART 2: Scientific Perspective + How to Avoid Unnatural Results

Welcome to part 2 of my blog series where we discuss ‘attractive lips’. In the first part, I covered various lip trends over the decades to demonstrate that trends come and go, but we always need to be cautious about blindly following trends as not every trend suits our face.

Science utilizes various mathematical lines and proportions, as well as the golden ratio, to determine ideal lips. I often use these as an aesthetic physician, although I use them more as a reference rather than absolute (!). Additionally, I take into account the individual’s facial structure and personal preferences. The most important thing is that YOU are happy with your lips, as you have to live with them every day.


If you would like to book a consultation and/or treatment for lip fillers, you can do so via this link. Also, take a look at the website of Doctor Contour Clinic!

Please note: The following text and video are a concise overview of what ideal lips are according to science. There are many more elements that are important. Please contact an expert in lip fillers to create your ideal lips! This video and blog post are for informational purposes only and cannot replace a personalized consultation with a good physician.

1. How Knowledge of Attractive Lips Can Avoid Unnatural Results Such as ‘Fish Lips’ and ‘Duck Lips’

In addition to volume, there are several other crucial elements that contribute to the beauty of lips. The shape, contour, proportion, and projection all play an essential role in creating an attractive mouth. You may be familiar with the infamous ‘fish lips’, where the volume is almost evenly distributed across the center and edges of the lips, or lips that protrude too far in profile, resembling a duck. These types of results often indicate lip augmentations that are not in line with scientific insights into what truly makes lips beautiful.

Source image: cosmedocs.com

2. The Rule of Thirds

The Rule of Thirds, emphasized by Leonardo Da Vinci, divides the face into three equal parts for aesthetic harmony. In the lower third, the distance from the nose to the lips should be one third, and from the lips to the chin, two thirds, for balanced facial proportions.

The rule of thirds divides the face into 3 equal parts. The lower 1/3rd is further divided into 2 parts (not shown in the photo), and this is important in determining the ideal lips for your face. Sometimes, chin fillers can be useful in creating more balance.

3. Golden Ratio

As an aesthetic physician, I always use the golden ratio as a reference for beauty. The golden ratio is also important in determining ideal lips: from the ratio between upper and lower lips to the width of the mouth to where the most volume in the lips should be to avoid the typical ‘fish look’.

4. Proportion between Upper and Lower Lips: Golden Ratio or 1:1 Ratio?

The proportions between the upper and lower lips vary by ethnicity and thus influence facial aesthetics. Among people of European descent, the golden ratio often prevails, with the upper lip slightly smaller than the lower lip. Conversely, African, Latin American, and Asian populations typically prefer a 1:1 ratio, sometimes with a slightly fuller upper lip.
Recent global trends, reinforced by social media, demonstrate a significant preference for this balance, deviating from the traditional golden ratio and emphasizing the dynamic nature of beauty standards.

5. Preferences in Lip Volume Vary According to Ethnicity

Additionally, we observe a striking difference in preferences for lip volume among different ethnicities.
Asians tend to prefer smaller lips compared to people of European descent, while Latin Americans prefer larger lips. Africans naturally have fuller lips, both frontally and in profile, and also prefer fuller lips.

6. Lips Seen from the Side

We need to consider lips from multiple perspectives, not just from the front view but also from the side view, which is crucial.
A good aesthetic physician uses the Ricketts line or E-line, drawing a line from the tip of the nose to the chin. The rule is that the lips should not exceed this line to maintain a natural appearance and avoid the infamous ‘duck lips’.

These ‘duck lips’ often occur when the treating physician lacks sufficient knowledge of aesthetic principles such as the Ricketts line.
Although there are differences between ethnicities, the general rule is that the upper lip ideally overlaps the lower lip by approximately 2 mm.

Additionally, it is necessary to assess whether the nose and chin are balanced with the lips. Sometimes, fillers may be needed in these areas to achieve a harmonious result.


After reviewing all the lip trends of the past decades, along with this concise overview of what science says about ideal lips, I would like to conclude with an observation of what ideal lips are now. Are they the lips of Clara Bow in the 1920s with the pronounced cupid’s bow, or the voluminous lips of Angelina Jolie, or the lips of Kylie Jenner?
The ideal lips are primarily those that are perfectly in harmony and balance with your specific face, taking into account your ethnicity, facial shape, and overall facial features. For example, Kylie Jenner’s lips may not suit a long, narrow face, and Angelina Jolie’s lips fit her well due to her fairly strong jawline, but may not fit another face.

It is especially important, if you are considering lip fillers, to choose a good physician who understands what makes lips beautiful and what will also look beautiful on your face (and not to forget, a physician who has received training in lip procedures so that the procedure is safe!).

If you would like to book a consultation or treatment with me as a physician, you can do so via the online booking form of Doctor Contour Clinic.

If you are considering enhancing your lips with fillers, then Doctor Contour Clinic is the right place for you. We do not believe in a ‘one size fits all’ approach, but strive for a personalized approach where we take into account your entire face and appearance to give you the most beautiful lips that suit you.

Book your consultation or treatment now!

Scientific References Used

  1. Heidekrueger PI, Juran S, Szpalski C, Larcher L, Ng R, Broer PN. The current preferred female lip ratio. J Craniomaxillofac Surg. 2017 May;45(5):655-660. doi: 10.1016/j.jcms.2017.01.038. Epub 2017 Feb 12.
  2. Heidekrueger PI, Szpalski C, Weichman K, Juran S, Ng R, Claussen C, Ninkovic M, Broer PN. Lip Attractiveness: A Cross-Cultural Analysis. Aesthet Surg J. 2017 Jul 1;37(7):828-836. doi: 10.1093/asj/sjw168.
  3. Baudouin JY, Tiberghien G. Symmetry, averageness, and feature size in the facial attractiveness of women. Acta Psychol (Amst). 2004 Nov;117(3):313-32. doi: 10.1016/j.actpsy.2004.07.002.
  4. Kar M, Muluk NB, Bafaqeeh SA, Cingi C. Is it possible to define the ideal lips? Acta Otorhinolaryngol Ital. 2018 Feb;38(1):67-72.
  5. Ding, A. (2021). The Ideal Lips: Lessons Learnt from the Literature. Aesthetic Plastic Surgery. doi:10.1007/s00266-021-02190-x


Hi there! I am Dr. Kim Detollenaere, aesthetic doctor and owner of 'Doctor Contour' aesthetic guide and clinic. I have been a content creator for several years, next to my busy medical life. Get to know more about me on Instagram, Youtube or check out the 'About me' page on this blog for more info!

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