As with other areas of the face, significant changes occur to the peri-oral region (around the mouth) with advancing age. These changes include loss or disruption of bone structure and dentition, volume loss and displacement of fat, weakening of supporting ligaments as well as soft tissue connective layers, and deterioration in the quality of the skin envelope. Flattening of the maxillary arch (mid-face bone) results in gradual posterior displacement of the base of the nose and upper lip. This change, in turn, leaves a relative excess or redundancy of the overlying soft-tissue around the mouth. Bone reabsorption in the lower jaw (mandible), particularly at the chin region (mentum), together with loss of fat and weakening of ligaments leads to an overall structural deficit of the lower lip. Furthermore, the corners of the mouth and lips (oral commissures) lose structural support leading to a downward tilt and development of marionette folds.

With age, the lips becomes thinner and laxer due to loss of elastin and collagen fibres and the sphincter-like muscle that surrounds the mouth (orbicular oris) undergoes atrophy (thinning). On the surface, these soft tissue changes lead to the gradual formation of wrinkles and grooves, typically in a vertical pattern leading to so-called smokers lines. The lips also become deflated and lengthens with loss of anterior projection (less pout). The red part of the lips loses both height and definition particularly in the midline, with apparent vertical thinning.

Of all the non-surgical filler treatments, lip augmentation often generates the greatest amount of anxiety and concern amongst patients. This is in large part attributable to the public perception of this procedure that is heavily biased by social and celebrity influences. These concerns are not without merit as, despite being one of the most challenging areas of the face to treat correctly, there is an alarming number of “practitioners” who provide lip augmentations despite being inadequately trained or lacking the necessary skills and understanding to perform this procedure to a high standard.

However, patients themselves sometimes have unrealistic expectations or misguided perceptions of what the ideal lip shape should be, often heavily influenced by their peers or social media. For instance, it is not uncommon for younger patients to seek large voluptuous lips, not in keeping with their overall facial profile; this results in over-volumised, over-projected and disproportionate lips.

The ideal lips possess several key aesthetic topographical landmarks, which provide shape, contour and, very importantly, definition to the lips. In addition to normal variation between different individuals, these defining points vary considerably between different races, gender and age.

Some of these landmarks appear subtle and yet even these, if ignored by either over- or even under-treatment, can lead to an ill-defined unnatural look. For example, the lower lip is divided into two halves with a midline groove (cleft) surrounded by a raised pillow-like structures (tubercles) either side. If the body of the lower lip is injected without preserving the tubercles and midline grooves, then the lips lose their definition resulting in an unattractive “sausage shape” appearance. Similar structures are present in the upper lip, which must also be preserved during treatment. 

It is not uncommon for patients, particularly from younger age groups, to request lip enhancements to match an “ideal” lip that they have seen such as on social media or a celebrity. These can lead some patients to seek dramatic changes to their lip shape and volume, which in turn can have undesirable consequences.

Each person’s lips are anatomically and structurally unique and individual to them and must be harmonious with overall facial features. There are considerable variations in lip shape as well as lip topography and defining points. Successful natural-looking lip treatments rely on enhancing a particular individual’s existing lip to achieve better shape, definition, projection, proportions and symmetry rather than attempting to mimic another individual’s lips. Moreover, a patient’s lips cannot be viewed in isolation but rather must be considered in relation to other facial features. For example, patients with large eyes and rounder softer faces can often get away with larger fuller lips than those with smaller eyes and squarer shaped faces.

There is debate about what constitutes the ideal proportions between the upper and lower lips. Classically a ratio of 1:1.6 is used, where the lower lip should should have a vertical height at the midline that is roughly 60% greater than the top lip.

However, other studies have suggested ratios ranging from 1:1 (both lips equal height) to 1:2 (bottom lip having twice the vertical height of the upper lip) at the midline. What is clear, however, is that the ideal proportions of the upper to lower lip can vary considerably between different individuals depending on their facial profile, race, age and gender. For instance, a 1:1 ratio may typically be desirable in a young patient or an Afro-Caribbean patient, yet a smaller upper lip (1:1.6 or 1:2) is usually preferable in middle-age to older patients, especially if Caucasian.

The shape/proportions and projection of lips are determined to a large extent by the underlying bony support of both the maxillary (midface) and mandibular (lower jaw) bones as well as the teeth. The latter is particularly important as malocclusion between the upper and lower teeth (such as an overbite and overjet) can substantially change the position of the upper lip relative to the lower lip as well as determine the degree of eversion and projection. Patients with significant dental malocclusion would benefit first from orthodontic treatment to correct this before undertaking a lip reshaping/augmentation procedure.

The corners of the mouth and the shape and support of the lips are also significantly affected by the structural support of the neighbouring facial regions. This relationship is particularly evident in older patients where bone and soft tissue volume loss and displacement is associated with soft tissue laxity and sagging in the cheeks and general mid-face area. These age-related changes, in turn, can alter the shape of the lips considerably leading to a downward turn in the corners of the mouth with associated marionette folds. Correspondingly, treating the midface first through a cheek augmentation can indirectly help lift the corners of the mouth and lips and soften the marionettes to a certain degree.

A substantial effect on lip shape is evident with changes in the profile of the chin. A weak under-projected chin is often associated with loss of vertical height of the lower lip and a relatively retruded lower lip that looks small in relation to the top lip from the front. Some of these patients also have an overactive mentalis chin muscle that causes an upward tilt of the chin soft tissue and deepening of the chin-lip groove (labiomental sulcus). This muscle hyperactivity, in turn, is associated with excessive eversion of the lower lip leading to under-projection relative to the upper lip. In this scenario, treating the lower lip first in these patients would lead to suboptimal results with persistent under-projection,

Chin augmentation with HA fillers (particularly at the lip-chin groove) allows a mechanical block of the undesired upward tilt. This effect leads to an elongation of the lower face through a cantilever rotation of the chin and a more balanced projection of the lower lip relative to the upper. 

Lips can also be made to look plumper using tiny doses of a temporary-acting muscle relaxant which is injected very carefully into specific lip muscles.  By rebalancing the pull of the muscles (through selective partial inhibition) in favour of the lip elevating muscles, a temporary gentle eversion or upturn of the upper lip is created (so-called “lip-flip”). The resulting increased visibility of the red part of the upper lip makes the lips look slightly fuller.

This method of treatment is a useful technique in patients who want a little bit more lip show without adding volume or for those who simply do not want to have their lips injected with fillers. Although this technique can be quite effective in some, it may not be a suitable option for all patients due to the nature of their lip anatomy. Furthermore, being a hypermobile region of the face, the results are short term, particularly when compared to fillers.