The nasolabial fold, also known as the nasogenian fold, is one of the earliest visible signs of facial ageing. Located between the wing of the nose and the corner of the mouth, it forms an anatomical transition zone where different aesthetic units of the face meet. The nasolabial fold is not simply an expression line : it is a structural fold whose depth and visibility depend on a combination of morphological, functional, and age-related factors.
Understanding the exact causes of the appearance of the nasolabial fold makes it possible to better anticipate its treatment, whether preventive or corrective. Contrary to common belief, this fold does not develop solely as a result of ageing, nor does it appear in the same way in every patient. It results from the gradual imbalance between the facial support structures, the subcutaneous fat compartments, the quality of the dermis, and the local muscular architecture.
Over time, the facial skin undergoes a series of biological changes. The production of collagen and elastin declines, dermal vascularization becomes less efficient, and the dermis gradually loses its ability to retain water. These changes, characteristic of intrinsic ageing, directly affect the suppleness, elasticity, and thickness of the skin in the nasolabial region.
This process is further accelerated by extrinsic ageing, mainly caused by chronic exposure to ultraviolet (UV) radiation, air pollution, smoking, and nutritional deficiencies. The skin becomes thinner, drier, and loses its mechanical strength. In this weakened environment, the nasolabial fold, which was previously visible only when smiling, gradually becomes permanent, remaining visible even at rest and leaving a lasting mark on the face.
One of the main causes of deepening of the nasolabial fold is the gradual loss of the fat compartments in the midface. With age, the deep adipose tissue located over the cheekbone and around the orbicularis muscle decreases in volume and gradually descends under the effect of gravity.
This volumetric loss results in reduced cheek projection and downward displacement of the facial tissues. This vertical movement mechanically accentuates the natural junction between the cheek and the upper lip, causing the nasolabial fold to deepen.
This process is particularly pronounced in individuals who experience rapid facial fat loss, whether related to significant weight loss, intense physical activity, or genetic factors. The face gradually loses its youthful softness and takes on a more angular and more severe appearance.
The face is supported by a complex network of retaining ligaments and fibrous septa that keep the soft tissues in place. Over time, these structures gradually lose their firmness and anchoring capacity. This laxity particularly affects the ligaments of the zygomatic arch as well as the malar and nasolabial septa, which play a key role in supporting the nasolabial region.
As these anchoring structures progressively weaken, even partially, the malar fat pad descends under the effect of gravity, leading to localized sagging of the tissues at the level of the nasolabial fold. This downward displacement contributes to the development of a deeper fold, sometimes asymmetrical, which cannot be corrected by treating the skin surface alone.
This mechanism explains why aesthetic approaches limited to superficial injection of the nasolabial fold often produce suboptimal results. In many cases, restoring facial harmony requires replacing lost volume and repositioning the supporting structures in order to address the true underlying cause of the fold.
The nasolabial fold is also influenced by the repeated contraction of certain facial muscles. The levator labii superioris alaeque nasi muscle and the orbicularis oris muscle are involved in movements such as smiling, speaking, and facial expressions.
In patients with particularly expressive facial movements, the repeated action of these muscles contributes to accentuating the nasolabial fold, which gradually becomes imprinted in the dermis through a process of mechanical creasing. This factor is even more significant when the skin has already been weakened by ageing or dehydration.
Although it is not a primary cause of the development of the nasolabial fold, this muscular factor acts as an aggravating element. This explains why some nasolabial folds become visible at an early age, sometimes as early as the age of 30, particularly in highly expressive individuals.
The shape and structure of the maxillary bone play a key role in the development and visibility of the nasolabial fold. In some patients, hypoplasia of the upper jaw is present, meaning that the underlying bone lacks adequate projection. This anatomical characteristic creates a more pronounced transition between the cheek and the upper lip, even in young individuals.
In these cases, the nasolabial fold may be congenital or become noticeable at an earlier age without necessarily being related to skin ageing. This anatomical configuration is common in certain Asian facial morphologies and in individuals with a relatively flat or less projected midface. It requires an individualized aesthetic approach, as simple superficial filling of the fold would be insufficient and could produce an unnatural result.
Among the indirect but significant factors contributing to the deepening of the nasolabial fold is oxidative stress, which refers to the cumulative damage sustained by skin cells as a result of environmental exposures and lifestyle habits. Chronic exposure to ultraviolet (UV) radiation, smoking, air pollution, lack of sleep, poor nutrition, and inadequate hydration all accelerate skin ageing.
These factors reduce the skin's natural collagen production, weaken the cutaneous barrier, and promote the development of wrinkles. The nasolabial fold, already affected by the mechanical mechanisms described above, becomes progressively more noticeable. Therefore, oxidative stress is not an isolated cause but rather an accelerator of tissue degeneration that should be considered in any strategy aimed at preventing or correcting the nasolabial fold.
It is common to see young patients, sometimes even before the age of 30, with a visible nasolabial fold despite the absence of significant skin laxity or obvious signs of ageing. This is explained by a combination of genetic, anatomical, and functional factors that predispose the tissues in this area to develop an early crease.
A lack of cheek projection, increased muscular activity, thin skin, a broad and dynamic smile, or rapid weight loss may all contribute to this phenomenon. In these situations, the nasolabial fold is not a sign of ageing but rather an aesthetic characteristic of the face that can be corrected if the patient wishes.
Stress has a significant impact on skin quality and accelerates facial ageing, including the deepening of the nasolabial folds. From a biological perspective, chronic stress leads to sustained release of cortisol, a hormone that impairs the skin's microcirculation, inhibits collagen production, and weakens the epidermal barrier. This cascade of changes promotes the development of thinner, less elastic skin that is more susceptible to mechanical creasing during facial movements. In addition, stress is often associated with involuntary muscle contractions of the face, particularly around the mouth and eyes, which over time contribute to the formation of expression lines, including the nasolabial folds. Stress should therefore be regarded as an aggravating factor that can accelerate the premature deepening of this vulnerable area of the face.
Regular alcohol consumption, even in moderate amounts, has a detrimental effect on the skin's physiological balance, with visible medium-term consequences, particularly on the development of wrinkles. Alcohol causes transient vasodilation followed by profound skin dehydration, thereby reducing dermal density and tissue firmness. It also interferes with liver metabolism and hormonal regulation, both of which are essential for collagen synthesis and cellular repair. By impairing skin quality, accelerating glycation of the supporting collagen fibers, and disrupting oxidative balance, alcohol indirectly promotes skin laxity and the loss of facial volume definition. Although alcohol alone does not cause nasolabial folds, it contributes to their earlier development and accentuation, particularly in individuals already exposed to other ageing factors.
The position adopted during sleep directly influences the development and progression of certain mechanical facial wrinkles, including the nasolabial folds. Consistently sleeping on one side places prolonged pressure on the side of the face compressed against the pillow, causing repeated creasing of the skin over the cheek and the nasolabial fold. Over the years, this asymmetric compression can contribute to more pronounced dermal creasing on one side of the face. To help prevent this form of mechanical ageing, it is advisable, whenever possible, to sleep on the back, which distributes pressure more evenly across the face. The use of ergonomic memory foam pillows designed to reduce pressure points, together with silk or satin pillowcases, may also help minimize friction and skin deformation during sleep. These measures contribute to preserving facial contours and reducing the development of wrinkles.
Article written by Dr Romano Valeria
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