Skin Care Education

Laugh Lines

The folds of skin running from the sides of the nose to the corners of the mouth. Also known as smile lines or nasolabial folds. A normal facial feature that deepens progressively with age.

What Are Laugh Lines?

Laugh lines is the widely used everyday term for the nasolabial folds: the natural folds of skin that run from the sides of the nose downward to the corners of the mouth. The same feature is also commonly referred to as smile lines. All three terms describe exactly the same anatomical structure.

Some degree of nasolabial folding is present in virtually every adult face and is a completely normal anatomical feature. The folds are most visible during smiling and other facial expressions that involve the muscles of the midface and cheeks, which is why the colloquial names emphasise the connection to smiling and laughing. In younger individuals with full midface volume and firm, elastic skin, the folds are typically mild and smooth out substantially when the face is relaxed. With age and the associated structural changes in the midface, the folds deepen and become more prominent even at rest, which is when they typically become a cosmetic concern.

Despite their name, the deepening of laugh lines with age is not primarily caused by smiling or laughing. The dominant driver of their progressive deepening is the loss of volume in the cheeks and midface that occurs as part of natural facial ageing. As the fat pads in the midface reduce, the skin and tissue above loses its structural support and descends, pushing into and deepening the fold from above. This means that laugh lines deepen as part of ageing regardless of how expressive an individual is.

Causes and Contributing Factors

Factor	Description
Midface volume loss	The primary driver of laugh line deepening with age. The fat pads of the cheeks and midface gradually reduce in volume from the 30s onward. As this volume is lost, the skin and tissue above it loses the structural support that was previously holding it in a lifted position. This tissue descends under gravity and pushes into the nasolabial fold from above, deepening it progressively.
Loss of skin elasticity	As collagen and elastin decline, the skin becomes less able to maintain its position and spring back from the repeated mechanical stress of facial expression. Reduced skin elasticity allows the fold to become more permanently established and more pronounced at rest.
Repeated facial expression	Smiling, laughing, and other expressions involving the cheek and midface muscles create repeated compression in the tissue adjacent to the fold. Over many years and thousands of repetitions, this contributes to the permanence of the crease, though it is a secondary rather than primary driver of fold deepening compared to volume loss.
Facial bone remodelling	Progressive remodelling of the midface bones with age reduces the underlying architectural support for the soft tissue of the cheeks and midface, contributing to tissue descent and fold deepening.
Weight loss	Significant reduction in facial fat, whether through overall weight loss or age-related volume reduction, removes the volume that was previously softening and supporting the nasolabial fold. Weight loss that reduces facial fat can make previously mild laugh lines noticeably more prominent.
Genetics	The natural facial anatomy, fat distribution pattern, rate of midface volume loss, and skin ageing characteristics are all significantly influenced by genetics. Some individuals develop deep laugh lines relatively early due to inherited facial structure rather than accelerated ageing.
UV exposure	Cumulative sun damage accelerates the decline of the structural proteins that maintain skin firmness and position, contributing to earlier and more pronounced fold deepening than would occur from intrinsic ageing alone.

Frequently Asked Questions: Laugh Lines

Yes. All three terms refer to the same anatomical feature: the folds of skin that run from the sides of the nose downward to the corners of the mouth. Nasolabial folds is the precise anatomical and clinical term, derived from the Latin words for nose and lips. Laugh lines and smile lines are the more widely used everyday terms that describe the same structure. The choice of term depends on context, but they are entirely interchangeable in meaning.

Because smiling is not the primary cause of their deepening. The dominant driver of progressive nasolabial fold deepening is the loss of volume in the midface and cheeks that occurs as part of natural facial ageing. As the fat pads in the cheeks reduce, the overlying tissue loses its support and descends, pushing into the fold from above. This process occurs regardless of how frequently a person smiles. Even an individual who makes minimal facial expressions will experience deepening of the nasolabial folds as midface volume reduces with age.

Yes. Nasolabial folds are a completely normal anatomical feature of the adult human face. They are present to some degree in virtually every adult and become visible during expression in virtually all people. Their increasing depth and prominence at rest is a normal age-related change rather than a sign of premature ageing. Whether and to what degree they are considered a concern is an entirely personal and subjective matter. Some people find deep laugh lines attractive and characterful. Others find them a source of concern as they deepen. Both responses are entirely valid.

Laugh lines, or nasolabial folds, run from the sides of the nose downward to the corners of the mouth. Marionette lines run from the corners of the mouth downward toward the chin. The two are adjacent and often develop together, but they are anatomically distinct. Laugh lines are fold above the mouth corners. Marionette lines are folds below the mouth corners. Both develop through similar age-related processes involving volume loss and tissue descent, but they affect different parts of the lower midface and lower face.