What Are Nasolabial Folds?

Nasolabial folds, the lines most people call smile lines, are the grooves that run from the sides of your nose down to the corners of your mouth. When your skin is young you barely notice them at rest. With age the skin loses elasticity and the muscle underneath weakens, and the grooves deepen until they stay visible even when your face is relaxed.

Why do nasolabial folds affect facial aesthetics?

Deep nasolabial folds read as a sign of age, and they can make the whole midface look older than it really is. They deepen as the face changes over time: the bone remodels, the muscle and skeletal support shrink, and the soft tissue shifts down. All of that pulls the face out of proportion.1

What causes nasolabial folds?

Two things drive the folds more than anything else: the facial muscles weaken, and the fat pads of the cheek sag downward. Thinner skin, extra fat, or weakened ligaments holding that fat in place then make the folds even more obvious.

Fat compartments

As the upper cheek fat pads slide down, they begin to overhang the nasolabial fold. The buccal fat below loses volume at the same time, so there is less underneath to prop the cheek pads up, which is what gives the deflated, aged look.7 The skin sits loose with too little volume beneath it to hold it taut. That is why dermal fillers can help: they replace the lost volume rather than shrinking the skin to aged proportions. Like the fat itself, though, fillers migrate or get absorbed over time, so they need redoing.

Ligament laxity

Using your facial muscles all day slowly stretches the ligaments that hold them in place, which lets the soft tissue drift.8 The zygomatic ligament, which supports the cheekbone, does the most damage here. As it loosens, the malar fat pads slide down and pool in the cheeks, carving out a sharp nasolabial valley.9

Skeletal remodelling

The skull is not one solid piece but a set of smaller bone segments, and some of those shift with age. The midface loses vertical height in particular, which packs the fat pads into a smaller area and pushes them outward, building more pronounced troughs and valleys as fat gathers around the cheeks. Women tend to lose more bone here than men, so there is evidence they are more likely to develop these folds.10 Anyone with a recessed maxilla or midface has less support holding the soft tissue taut, which makes them prone to the folds at any age.11

How to prevent nasolabial folds?

You cannot avoid nasolabial folds completely, since some grooving comes with a healthy smile. What you can do is slow how deep they get, and that comes down to good anti-ageing care.

Sun damage

Sun protection matters more than almost anything else for keeping skin elastic. UV exposure adds up day after day and breaks down the collagen that keeps skin taut and young. It also increases skin laxity and yellowing, on top of the cancer risk everyone already worries about.

A 2013 study by Flament and colleagues12 found that skin with 85% or more sun damage looked at least 3 years older than the person's real age, while skin with slightly less damage, around 78%, looked up to 3 years younger.

Smoking damage

Smoking darkens the skin, since cigarettes push the melanocytes that make melanin to ramp up.13 It also thins the skin at the cheeks, one of the same factors behind nasolabial folds.14 More than that, it changes the physical makeup of the skin, leaving it thicker in some spots and thinner in others, which lowers skin density and elasticity. Hydration drops too, in both men and women who smoke, partly from reduced blood flow.15

How are nasolabial folds corrected surgically?

The obvious move is dermal filler to soften the depth of the groove. But Dr Souphiyeh Samizadeh points out that this often creates disharmony, because it is a temporary fix on a face that is ageing everywhere. A youthful midface from fillers can clash with an ageing forehead and brow. She also warns that injecting in the wrong spot adds mass to the cheeks and makes them sag even more. A few alternatives are worth knowing about.

Non-ablative radiofrequencies

Electromagnetic waves shake the water molecules in the skin to create heat. Lax skin is warmed at the dermis to 50 to 70 degrees C, where collagen fibres reshape under the heat and shrink by about 30%. That tightens the skin and pushes new collagen to form over the following weeks.³

Botulinum toxin (Botox)

Botulinum toxin is usually injected into the nasolabial muscles that flare the nostrils and lift the upper lip, the levator labii superioris alaeque nasi.⁴ This relaxes the muscle and smooths the groove, though treating this area carries more risk because it sits so close to the muscles around the mouth.⁵

Surgical threads

Serrated polypropylene threads are used to stitch the loose soft tissue back into the right position. They give structural support against gravity without the puffiness and added bulk of an implant.⁶

Fillers earn their place when they target the underlying causes above rather than the surface. Correcting these folds properly means restoring lost midface volume, easing skin laxity, and making up for the stretched ligaments. Support the sagging tissue and replace the volume, or the problem comes back, often worse. Lean on fillers alone and you can push the fold toward the middle of the face, which looks worse and gives that telltale botched look. Filling here also takes care to avoid the facial artery, which is why it is usually done in several smaller volumes.