Nasolabial Folds and Smile Lines: Why the Crease From Nose to Mouth Was Filler's First Target and Is Now Its Most Overtreated, Why the Fix Usually Sits in the Cheek Above It, Where the Artery Runs, and Why a Facelift Softens It Less Than Patients Expect

The nasolabial fold has the odd distinction of being both the most treated and the least necessary target in facial injectables. It is the crease that runs from the side of each nostril down to the corner of the mouth, the one people call smile lines or laugh lines, and it was the line on which nearly every dermal filler sold in the United States earned its approval. When the FDA cleared Restylane in December 2003, the indication was the correction of moderate to severe facial wrinkles and folds, "such as nasolabial folds," and the pivotal trial had been run on that fold alone. Juvederm, Radiesse, Belotero, Sculptra, and the permanent filler now sold as Bellafill followed the same path. For a decade, the nasolabial fold was what filler was for.

It is also something everyone has. A toddler has a nasolabial fold. It is the boundary between the cheek, which moves with every smile, and the upper lip, which is held close to the teeth, and it deepens when the cheek rises. A face without one does not look young; it looks inflated, and the overfilled, smooth-cheeked look that critics of the industry call pillow face is, in large part, the result of a decade of injectors filling a crease that was never the problem. What changes with age is not the existence of the fold but its depth at rest, and that depth is set mostly by what sits above and beneath it.

This piece covers what the fold actually is and why it deepens, why the cheek and the base of the nose are usually the better places to treat it, where the angular artery runs and why the upper end of the fold is one of the more dangerous filler sites on the face, what a facelift does and does not do to the fold, and how to tell whether a consultation is treating your face or your crease.

What a nasolabial fold actually is, and why it deepens

The short answer: the nasolabial fold is a natural boundary where the mobile fat of the cheek meets the tethered skin of the upper lip, present at every age; it deepens at rest when the cheek fat above it deflates and slides forward and down, when the bone of the upper jaw and the edge of the nasal opening recede, when the skin thins, and when the lip-elevating muscles pull it deeper with every expression, and only the last two are problems in the crease itself.

The fold sits where two different kinds of soft tissue meet. Lateral to it is the cheek, a layered structure of skin, fat, the superficial fascia that surgeons call the SMAS, and the muscles of facial expression. Medial to it is the upper lip, where the skin is bound tightly to the orbicularis oris muscle beneath and there is almost no fat to move. Rod Rohrich and Joel Pessa's 2007 mapping of the facial fat compartments in Plastic and Reconstructive Surgery identified a discrete pocket they called the nasolabial fat compartment, sitting just lateral to the fold and in front of the medial cheek fat, and showed that the fold forms along the border of that pocket. When a person smiles, the zygomaticus major and the levator muscles of the lip pull the cheek upward and back, the cheek fat bunches against the fixed lip, and the crease deepens. That is the smile line, and it is how a face communicates warmth.

With age, three things change underneath it. The deep fat compartments of the midface, especially the deep medial cheek fat that lies against the bone, lose volume. Pessa's later work and Rohrich's described how this deflation removes the support that held the superficial nasolabial fat up and back, so that the superficial pad slides forward and down over a lip that cannot move with it. The piece on Ozempic face describes the same process happening in months rather than decades when weight is lost quickly, and why the nasolabial fold is one of the first places it shows.

The bone recedes too. Robert Shaw and David Kahn's computed tomography studies at the University of Rochester, published in the late 2000s, measured the facial skeleton across age groups and found that the maxilla retrudes and the pyriform aperture, the pear-shaped bony opening of the nose, enlarges with age, particularly along its lower and outer edge. That edge is the floor under the top of the nasolabial fold. Bryan Mendelson and Chin-Ho Wong's 2012 review in Aesthetic Plastic Surgery drew the conclusion that matters for patients: the soft tissue of the midface drapes over a skeleton that is shrinking selectively in exactly the regions that support it, so that the fold deepens even in a person who has gained no laxity. The piece on facial implants covers the surgical response to a deficient midface skeleton, and premaxillary implants placed at the base of the nose exist for this problem.

The skin is the smallest contributor and the one most treatments address. Ultraviolet exposure and age thin the dermis and degrade its elastic fibres, the process the piece on skin thinning with age describes, and a crease that used to unfold when the face relaxed starts to stay etched. That etched line in the floor of the fold is a skin problem, and it is the only part of the fold that resurfacing reaches.

The fold also differs by face. People with fuller cheeks, which often means younger people, darker skin types, and people with naturally prominent malar fat, have deeper folds earlier, and the fold in those faces is a sign of volume rather than of loss. People with long upper lips or a retruded upper jaw show a deeper fold at every age. Before any treatment the useful question is not how deep the fold is, but whether it has changed, and the most honest tool for that is a photograph from ten years ago.

Why filling the crease stopped being the answer, and where the better targets are

The short answer: filler threaded directly into the nasolabial crease softens it for six to twelve months and was the standard approach for a decade, but it adds volume beside a cheek that is already sliding forward, so the face becomes fuller without becoming younger, the upper lip becomes heavier and longer, and repeated treatment builds the overfilled midface that injectors now spend time dissolving; the fold usually softens more, and looks more natural, when volume goes deep on the bone of the cheek and at the base of the nose, with the crease treated last and least.

The first generation of filler practice treated the fold as a wrinkle. An injector would run a linear thread of hyaluronic acid along the crease, or fan it out in the deep dermis beneath, and the line would soften in the mirror immediately. The pivotal trials measured exactly this: the Wrinkle Severity Rating Scale, a five-point photographic grading of fold depth, at six months. By that measure the products worked, and the measure shaped two decades of practice.

The problem was not the first session. Filler in the crease raises the floor of the valley without touching the hill beside it, so the cheek fat that has descended over the fold still sits there, now beside a slightly higher crease. The face reads as fuller and flatter rather than lifted, and the overhanging cheek can look heavier because the valley that used to define its edge is gone. Product placed close to the lip also adds weight to a structure that is already lengthening with age, and the piece on the surgical lip lift explains why a long upper lip is a sign of age in its own right. Each year, as the cheek continues to descend, the injector fills a slightly deeper fold, and because hyaluronic acid in the face persists far longer than the labels state (the imaging studies in the piece on filler migration found product years after injection), the volumes stack. After five or six years the midface is smooth, wide, and convex, with the nasolabial fold no shallower than it started relative to the cheek beside it.

Injectors began to say this out loud in the early 2010s. The expert consensus statements on midface rejuvenation published in that decade, in journals such as Plastic and Reconstructive Surgery and Dermatologic Surgery, shifted the emphasis from the fold to the structures supporting it: restore the deep medial cheek, support the base of the nose, and treat the crease itself only for what remains. The phrase that circulated among trainers was that the nasolabial fold should be the last syringe, not the first.

There is a legitimate place for treating the crease directly. A patient with good cheek support and an etched line in thin skin, often someone in their late fifties or older with a lean face, can have that line softened with a small volume of a soft, low-density hyaluronic acid placed in the superficial to mid dermis, or with a skin-quality product rather than a structural one. The piece comparing biostimulatory and hyaluronic acid fillers covers the product families. The goal in that face is to blur a crease, not to fill a valley, and the volume is measured in tenths of a millilitre rather than syringes.

The exit from an overfilled fold is hyaluronidase. The piece on dissolving filler covers how it works and what to expect when years of product are removed at once: the face can look briefly older than it did before treatment began, because the product was masking real descent. The piece on delayed filler nodules covers the inflammatory lumps that can appear months or years later, and the perioral region, mobile and close to the oral flora, produces them more than most sites.

The better targets sit above and beneath the fold, and the rationale for treating the cheek first is mechanical. If the nasolabial fat pad slides forward because the deep medial cheek fat beneath it has deflated, then restoring the deep compartment should reposition the superficial one, at least partly. Hyaluronic acid or calcium hydroxylapatite placed on the periosteum of the cheekbone, usually in two or three points along the zygoma and the anterior maxilla, does this in a measurable way in some studies and a modest way in most. A small number of trials and a larger body of observational and imaging work found that cheek augmentation alone reduced nasolabial fold severity by roughly a grade on the standard scale in a meaningful proportion of patients. The effect is real and it is not dramatic. It is greatest in patients whose cheeks have visibly flattened and smallest in patients whose cheek bones were always prominent and whose fold is a matter of descended fat rather than lost support.

The base of the nose is the second target. A small volume of firm filler placed deep against the bone at the pyriform aperture, just beside and below the nostril, replaces some of the bony support the aging maxilla has lost and lifts the uppermost part of the fold, the part that tends to look like a shadow beside the nostril rather than a line. This is also where the injection is most dangerous, for reasons covered in the next section, and it is a deposit placed with a needle on bone or a cannula in a known plane by someone who knows the anatomy, not a thread run along the skin.

The limits deserve emphasis. Cheek filler can lift a descended nasolabial pad by a few millimetres; it cannot return a heavy pad to the position it held at thirty. Adding volume to a cheek to correct a fold beneath it is a trade, and past a certain volume the cheek becomes wide and convex, the eyes look smaller, and the face takes on the overfilled look that patients and the public now recognize on sight. The piece on the Sculptra timeline covers the slower, diffuse alternative that some patients prefer for the cheek precisely because it builds gradually and is harder to overdo, and the piece on fat transfer to the face covers the surgical version of the same idea: the patient's own fat, harvested and grafted in small parcels into the deep cheek and the pyriform area, with a longer potential life and a less predictable take.

There is one target that pulls in the opposite direction. Some patients, usually younger ones with full faces, ask about buccal fat removal to sharpen the cheek, and the fold is part of the conversation because a full lower cheek bunches against it when they smile. The piece on buccal fat removal at five years explains why removing fat from a face that will lose it naturally over the next two decades is a choice that tends to age poorly, and that the nasolabial fold and the hollow beneath the cheekbone are where the regret shows.

Toxin has a small role. The levator labii superioris alaeque nasi, a thin muscle that runs from the side of the nose to the upper lip, pulls the top of the fold deeper when it contracts, and a unit or two injected into it, the same injection used for the gummy smile described in the piece on excessive gingival display, can soften the upper fold in an animated face. The trade is that the same muscle helps lift the lip in a smile, so too much toxin lengthens the upper lip and flattens the smile. It is an off-label refinement, not a treatment for a fold caused by descent.

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The nasolabial fold is not a flaw to be erased. It is the edge of the cheek, and everyone has one. What ages a face is the cheek sliding forward over that edge and the bone receding beneath it, and a crease filled to perfection beside a cheek that is still sliding produces a face that is full everywhere and young nowhere.

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Where the artery runs, and why the top of the fold is a high-risk site

The short answer: the facial artery travels up alongside the nasolabial fold and continues as the angular artery toward the inner corner of the eye, where it connects to branches of the ophthalmic artery; filler that enters it, most often near the base of the nose at the upper end of the fold, can block the skin of the nose and lip and, rarely, travel back to the eye, so the fold is consistently listed among the leading sites of filler necrosis and filler blindness.

The anatomy is not subtle. The facial artery crosses the jawline in front of the masseter, runs upward and forward past the corner of the mouth, and then ascends roughly along the line of the nasolabial fold toward the side of the nose. Near the alar base it gives off the lateral nasal artery to the nostril and continues as the angular artery up the side of the nose to the inner corner of the eye, where it anastomoses with the dorsal nasal branch of the ophthalmic artery. Its course varies from person to person. Cadaver and ultrasound studies have found it running beneath the fold, medial to it, lateral to it, and in some faces superficially enough to be injected with a short needle, and the depth changes along the length of the fold. Near the alar base, where injectors place volume to treat the upper fold, it is often at its most superficial.

When filler enters the artery, two things can happen. If it travels downstream, it blocks the skin the vessel supplies: the side of the nose, the nostril rim, and the upper lip. The early signs are blanching, then a dusky, mottled, net-like discoloration, usually with pain that seems out of proportion to the injection. Untreated, the skin can die, and the nasal ala, a small structure with a precarious blood supply, is a classic site of necrosis after nasolabial filler. If enough pressure pushes filler backward up the angular artery into the ophthalmic circulation, it can reach the retinal artery, and the result is sudden, usually permanent, vision loss in that eye. The systematic reviews of filler-related blindness published by Katie Beleznay and colleagues in 2015 and updated in 2019 identified the nasolabial region among the four or five sites most often involved, along with the glabella, the nose, and the forehead. The piece on filler vascular occlusion covers the whole chain in detail, including what an injector should do in the first minutes.

The safety precautions that matter are known and not exotic. Deep injection on bone at the pyriform aperture, or a blunt cannula in a consistent plane, reduces but does not eliminate the risk. Small volumes, slow injection at low pressure, and aspiration with the honest understanding that a negative aspiration does not guarantee safety are standard practice. Hyaluronidase must be in the room and the injector must know the high-dose protocol for occlusion. Hyaluronic acid has this antidote; calcium hydroxylapatite and poly-L-lactic acid do not, which is one reason many injectors avoid non-reversible products near the alar base. Permanent fillers in the fold carry the long-term risks described in the piece on illegal silicone and biopolymer injections in their extreme form and in milder form even when the product is approved.

This is why the question of who is holding the syringe matters more here than at a forehead toxin appointment. The piece on who is injecting you covers the supervision rules that vary by state and the training gap between an injector who has done a weekend course and one who has dissected the region. The upper nasolabial fold is not a beginner's site, and the commonness of the request does not make it a low-risk one.

Surgery, threads, devices, and what a facelift actually does to the fold

The short answer: a facelift that releases the cheek's retaining ligaments and repositions the midface, as the deep plane operation does, softens a nasolabial fold caused by descent more than any injectable, but the fold is the region of the face that surgery corrects least completely, because the lip side of it is anchored; threads and energy devices produce small, temporary changes, resurfacing addresses only the etched crease, and direct excision of the fold is reserved for older faces willing to trade a crease for a scar.

Surgeons have argued about the nasolabial fold for as long as there have been facelifts. The classic skin-only lift pulled the skin of the cheek backward toward the ear and did almost nothing for the fold, because the fold is formed by fat and fascia, not skin, and the piece on the quiet end of the pull-tight facelift explains why that operation made faces look swept rather than younger. The SMAS techniques that followed, which tighten the fibrous layer beneath the skin, improved the jowl and the jawline more than the fold, because the SMAS pull is mostly lateral and the fold sits medial to where the tension reaches.

The deep plane facelift, popularized by Sam Hamra in the early 1990s and refined by later surgeons, was designed in part to address this. By releasing the zygomatic and masseteric retaining ligaments and lifting the cheek fat together with the SMAS as a single flap, it moves the descended malar and nasolabial fat back up over the cheekbone. The piece on the deep plane facelift describes the operation. Comparative studies, mostly retrospective and from surgeons who favor one technique or the other, have generally found that the midface and the fold improve more with deep plane release than with SMAS plication, though the size of the difference is debated and the improvement in the fold is the most variable outcome of any facelift. Even after a well-executed lift, most patients keep a visible fold, because the lip side of it is fixed and the operation is moving only one side of the boundary. Many surgeons add fat grafting to the cheek and the pyriform area at the same operation for exactly this reason.

The piece on the mini facelift covers the short-scar operation many patients with early aging are offered; it is a lower-face operation and, as a rule, it does very little for the nasolabial fold. The piece on the limits of the non-surgical facelift covers the broader argument for why no combination of injectables recreates what repositioning does.

Threads are marketed for the midface more than any other area, and the piece on PDO thread lifts covers the evidence: barbed absorbable sutures can lift the cheek fat for weeks to a few months before they lose their grip, and the fold returns. Energy devices, radiofrequency and focused ultrasound, covered in the piece on energy-based skin tightening, tighten skin modestly and do not move a fat pad. Resurfacing, described in the piece on ablative and non-ablative laser, is the right tool for an etched line at the floor of the fold and for the vertical lines of the upper lip the piece on lip lines covers, and the wrong tool for anything deeper.

Two operations target the fold directly, and both are rare. Direct excision removes an ellipse of skin and fat along the crease and closes it as a line that sits in the old fold; in an older patient, often a man with thick, deeply creased skin and heavy cheek tissue who does not want a facelift, the scar can be nearly invisible within a year. In a younger or smoother face it is not. Liposuction or direct excision of the nasolabial fat pad itself, offered occasionally for a heavy pad above the fold, removes fat from a region the face will lose naturally over time and risks the hollow, deflated midface that is harder to correct than the fold ever was.

Plan by face, what it costs, and who should leave the fold alone

The short answer: a fold that has not changed much and appears mainly when smiling needs nothing; a fold deepened by a flattened cheek is a deep cheek filler or fat grafting case with the crease treated last; a fold beside a heavy, descended cheek and jowl is a facelift case in which filler is a bridge; an etched line in thin skin is a small soft-filler or resurfacing case; and a midface that has been filled for years and looks wide is a dissolving case first.

The patterns are worth stating plainly. The patient in their thirties or early forties with full cheeks whose folds show mostly in smiles and photographs has a normal face and the honest treatment is nothing. Filling that fold now starts a cycle of maintenance on a structure that does not need it, and the full cheek that defines the fold will thin on its own schedule.

The patient in their late forties or fifties whose cheeks have visibly flattened and whose fold has deepened at rest is the structural injectable case. One to two syringes of a firm hyaluronic acid on the bone of the cheek and a small deposit at the base of the nose, with the crease itself treated only if a line remains, is a reasonable first plan. In Los Angeles a syringe of mainstream hyaluronic acid filler runs about seven hundred to twelve hundred dollars, so a first session is roughly fifteen hundred to thirty-five hundred, with maintenance every twelve to eighteen months at lower volume. The piece on what a plastic surgery quote covers puts the cost of the surgical alternatives in context.

The patient with heavy cheek fat sitting over the fold, a jowl, and a fold that largely disappears when they lie flat on their back is the facelift case. The recline test described in the piece on marionette lines works for the nasolabial fold too: lie flat, look up into a hand mirror, and watch the fold. If it softens markedly, gravity and descent are doing most of the work, and the treatment that addresses that is repositioning. Injectables in that face are a bridge or a choice to decline surgery, and both are legitimate when named as such.

Some patients should leave the fold alone or address something else first. Patients who have recently lost a large amount of weight should wait until it is stable, since their faces are still changing. Patients with a facial palsy whose fold is flattened on one side need a facial nerve specialist rather than filler on the other side to match. Patients with facial lipoatrophy from HIV treatment or Parry-Romberg syndrome, covered in the piece on facial lipoatrophy, have a different problem with different reimbursement and product indications. And patients who have been filled repeatedly and are told they need more should ask for hyaluronidase to be discussed first, and should be wary of any practice that does not raise it.

The honest summary

The nasolabial fold is the line on which modern filler was built, and it is the line the field has learned to treat least directly. Everyone has one, because it is simply the edge of the cheek where it meets a tethered lip, and it deepens at rest when the cheek fat deflates and slides forward, the bone at the base of the nose recedes, and the skin thins. Filler threaded into the crease softens it for a season and, repeated for years, produces a wide, heavy midface without making the face look younger. The better targets are usually the deep cheek and the bone beside the nostril, and the crease itself gets what is left over, if anything. The upper end of the fold sits over the angular artery, which connects to the circulation of the eye, so this is a site for an experienced injector with hyaluronidase in the room, not a quick add-on. A facelift that repositions the midface softens a descent-driven fold more than any injectable, though less completely than it improves the jawline, and many surgeons add fat to the cheek at the same time. Bring an old photograph, ask where the product is going and why, ask what happens if the skin turns white, and remember that a fold you have had since childhood is not something that needs to be fixed.