Skin Care Education

Nasolabial Folds

The anatomical skin folds running from the sides of the nose down to the corners of the mouth. A normal facial feature present in all adults that deepens progressively with age. Also known as smile lines or laugh lines.

What Are Nasolabial Folds?

Nasolabial folds are the natural folds of skin and soft tissue that run from the sides of the nose downward to the corners of the mouth. The term is derived from the Latin words for nose and lips, reflecting the anatomical course of the fold from the nasal base to the lip commissure. They are also widely referred to by the colloquial terms smile lines and laugh lines, though all three names describe exactly the same anatomical structure.

Nasolabial folds are a completely normal anatomical feature of the adult human face. They are present to some degree in virtually every adult and are a natural consequence of the way the cheek tissue, the lip elevating muscles, and the skin of the midface interact during facial expression. Their visibility varies considerably between individuals based on facial anatomy, skin thickness, and the degree of midface volume present. In younger individuals with full cheeks and firm skin, the folds are typically mild and become most visible during smiling. With age, they deepen and become progressively more prominent even at rest.

Despite being associated in name with smiling and laughing, the primary driver of nasolabial fold deepening with age is not facial expression but the progressive loss of volume in the midface and cheeks. As the fat pads of the midface reduce with age, the overlying skin and soft tissue loses its structural support and descends under gravity. This descending tissue accumulates in and deepens the nasolabial fold from above. The fold therefore deepens as a direct consequence of structural ageing rather than as a result of how frequently or expressively a person smiles.

Causes and Contributing Factors

Factor	Description
Midface volume loss	The primary and dominant driver of nasolabial fold deepening with age. The fat pads of the cheeks and midface gradually reduce from the 30s onward. As this volume decreases, the skin and soft tissue above it loses structural support and descends under gravity, pushing into and deepening the nasolabial fold from above. This process occurs regardless of facial expressiveness.
Loss of skin elasticity	As collagen and elastin decline, the skin of the midface and cheeks becomes less able to maintain its position against the effects of gravity and the mechanical stress of repeated expression. Reduced skin elasticity allows the fold to deepen progressively and to become more permanently established.
Repeated facial expression	The zygomaticus major and other cheek-elevating muscles contract during smiling and laughing, compressing the tissue adjacent to the fold. Over many years and thousands of repetitions, this repeated mechanical compression contributes to the permanence of the crease, though this is a secondary rather than primary driver compared to volume loss.
Facial bone remodelling	Progressive remodelling of the midface bones with age, including reduction in cheekbone projection and midface bony volume, reduces the underlying architectural support for the cheek and midface soft tissue, contributing to tissue descent and fold deepening.
Retaining ligament laxity	The zygomatic and masseteric retaining ligaments anchor the cheek tissue to the underlying facial skeleton. As these ligaments elongate and weaken with age, they allow the cheek tissue to descend more freely, directly contributing to the deepening of the nasolabial fold.
Weight loss	A significant reduction in facial fat removes the cheek volume that was previously softening and supporting the nasolabial fold. Even modest facial fat reduction can make previously mild folds noticeably more prominent.
Genetics	Natural facial anatomy, fat distribution pattern, rate of midface volume loss, and skin ageing characteristics are all significantly influenced by genetics. Some individuals have naturally deep nasolabial folds from early adulthood due to inherited facial structure rather than ageing.

Frequently Asked Questions: Nasolabial Folds

Yes. All three terms refer to the same anatomical feature: the folds of skin and soft tissue running from the sides of the nose downward to the corners of the mouth. Nasolabial folds is the precise anatomical and clinical term used in medical and professional aesthetic contexts. Smile lines and laugh lines are the more widely used everyday terms that describe the same structure by reference to the expressions during which they are most visible. The choice of term depends on context but they are entirely interchangeable in meaning.

Yes. Nasolabial folds are a completely normal anatomical feature of the adult face. They are present to some degree in virtually every adult and become most visible during smiling and other expressions involving the cheek and midface muscles. Their increasing depth and prominence at rest as part of the natural ageing process is a normal age-related change. Whether or to what degree any individual considers them a cosmetic concern is a personal and subjective matter. Many people have prominent nasolabial folds and consider them a characteristic part of their face rather than something to be addressed.

Because the primary driver of their deepening is not smiling but the loss of volume in the midface and cheeks that occurs as part of natural facial ageing. As the fat pads of the midface gradually reduce, the overlying tissue loses its support and descends, pushing into the nasolabial fold from above and deepening it. This process is driven by structural changes within the face rather than by surface-level muscle activity, and it proceeds regardless of how frequently or expressively an individual smiles.

Nasolabial folds run from the sides of the nose downward to the corners of the mouth. Marionette lines begin at the corners of the mouth and continue downward toward the chin. The two are adjacent and sequential: the nasolabial fold ends at the mouth corner where the marionette line begins. Both are common age-related changes to the lower face that develop through similar mechanisms of volume loss and tissue descent, and they frequently occur together. However, they are anatomically distinct, affect different regions of the lower face, and are sometimes addressed through different approaches.