Nasolabial Fold Filler

What Is Nasolabial Fold Filler?

Nasolabial fold filler is the injection of hyaluronic acid gel into and around the fold that runs from the side of the nose down to the corner of the mouth (the nasolabial fold). The name comes from two Latin roots meaning ‘nose’ and ‘lip’, and it describes where the fold lies between these two structures.

Hyaluronic acid fillers have been studied in detail in this area in randomised controlled trials (trials in which participants are randomly assigned to groups that are then compared), and more than one meta-analysis has pooled the results of these trials. A meta-analysis pooling randomised trials of filler treatments in the nasolabial area concluded that the treatment gives a satisfactory and sustained improvement. Another analysis, pooling thirteen randomised trials, also assessed hyaluronic acid as a safe filler for this area.

Hyaluronic acid gel breaks down over time and can be dissolved with the enzyme hyaluronidase. According to a review of filler complications that cause permanent damage, hyaluronic acid fillers continue to be preferred because they can be reversed in this way. When the clinic assesses a product, approval by the US Food and Drug Administration (FDA) is not, on its own, the deciding criterion; the assessment is based on the product’s CE marking, its registration and conformity status in Türkiye, and the manufacturer’s intended purpose.

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Why Does the Nasolabial Fold Deepen?

There is no single cause of a deepening nasolabial fold. In research, reduced skin elasticity, changes in the fat compartments of the mid-face and sagging of the upper cheek stand out as factors that together make the fold more prominent; which of these weighs most varies from person to person.

In a study that examined photographs of Japanese women aged 20 to 60, the severity of the fold increased significantly with age. In the same study, among middle-aged women, the fold became more severe as skin elasticity decreased and as the subcutaneous fat (the fat layer under the skin) became thicker. The researchers think these changes may make the fold more prominent by causing sagging in the upper cheek. However, the study was carried out in a single population and in women only.

Volume loss can also play a part by a separate route. According to anatomical research based on cadaver studies, when the fat compartment that lies deep in the cheek, close to the nose (the deep medial cheek fat compartment), loses volume, the skin is left in excess of the tissue beneath it and the fold looks more prominent than it really is. The researchers call this appearance of sagging without true sagging ‘pseudoptosis’. The recognition that facial fat is made up of separate compartments marked the start of a shift away from explaining ageing by gravity alone, towards a view that also takes volume change into account.

A review of how the fold forms divides the nasolabial fold into three types with different causes and ways of forming. It also notes that age-related changes in the skin and connective tissue progress differently in different areas of the face, because of differences in tissue firmness and thickness. What this means for you: two folds that look the same may not have the same cause. You can read how volume loss is told apart from sagging in the guide article Volume loss or sagging?.

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The Link Between the Mid-Face and the Fold

The depth of the nasolabial fold cannot be separated from the volume of the mid-face: the greater the lack of volume in the mid-face, the more prominent the fold. However, the widespread impression that cheek filler pulls the fold upwards is not supported by research. These two points need to be considered together.

This relationship was shown in a large study carried out online. In this study, 3,553 people rated their own mid-face, tear trough and nasolabial folds using photographic scales; as mid-face volume deficiency increased, fold severity increased in both women and men. The relationship held even after age and other demographic factors were taken into account. However, this is a self-assessment study: it shows that the two conditions occur together, not that one causes the other.

On the treatment side, a randomised split-face study (one side of the face compared with the other) tested three methods: deep injection into the middle and outer part of the cheek, injection directly into the fold, and the two combined. Four to six weeks after treatment, assessors who did not know which method had been used found improvement with all three methods, and there was no statistically significant difference between them. Patients slightly preferred the combined treatment, which used the most product. However, the follow-up period was short.

Another study, using three-dimensional photography, gives a more cautious picture. In 77 people who had hyaluronic acid injected into the cheek, the skin expanded outwards from the injection point and perpendicular to the skin surface. In the 37 of them whose facial expression was the same before and after treatment, no pulling effect from the cheek towards the fold could be shown, and no difference in the fold could be detected on the photographs. The only people whose photographs showed improvement in the inner part of the face were those who had filler placed directly in the transition zone between the fold and the cheek.

In short, the link between the mid-face and the fold does not mean that every fold can be corrected through the cheek. If there is a true lack of volume in the mid-face, it needs to be assessed separately. You can find details about the cheekbones and cheeks on the Cheek Filler page.

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What Do Randomised Trials Show?

Many randomised trials show that hyaluronic acid filler reduces the severity of the nasolabial fold in the short and medium term. The same trials also show that the effect decreases over time.

In a meta-analysis pooling randomised trials in this area, the average wrinkle severity score was 3.23 at the start and fell to 1.79 one month after treatment; it was 2.02 at month 6 and 2.46 at month 12. In other words, at month 12 there is still improvement compared with the start, but it has fallen back from the level seen in the first month. This analysis looked not only at hyaluronic acid but also at other soft-tissue fillers used in the area.

Hyaluronic acid fillers are not all the same. In an analysis pooling a total of 1,190 patients from fourteen randomised trials, improvement in the fold differed according to the structure of the gel (single-phase or two-phase), but no difference was seen in how often adverse effects occurred. A recent analysis comparing products with and without lidocaine, a local anaesthetic (numbing medicine), also reported that products with lidocaine significantly reduced pain during the procedure and were similar in terms of improvement and safety; however, the number of studies on this is limited.

In these trials, the outcome is assessed with scales that grade the severity of the fold. For example, a photographic scale that describes the hollowing and shadow of the fold in five grades could be used by trained assessors with almost complete consistency, and a difference of one grade could be detected. Scales do not promise a result; they make it possible to describe the same fold in the same terms before and after treatment. The figures here are averages from published studies, not results from this clinic.

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Limits of This Treatment

Nasolabial fold filler aims to reduce the depth and shadow of the fold; it does not remove the fold. This fold is a natural boundary between the cheek and the upper lip. The aim of filler is not to erase this boundary but to make a deepened fold less prominent.

Loss of skin elasticity and sagging of the upper cheek have been reported to play a part in the fold deepening, but they are not problems that filler targets directly; filler addresses the volume-related part of the picture. The impression that cheek filler stretches the skin and pulls the fold upwards has also not been confirmed by three-dimensional measurements. For this reason, in a face with marked skin laxity, filler alone may not achieve the expected result.

The effect is not permanent. The meta-analysis pooling randomised trials in this area found that the improvement achieved in the first month partly fell back by month 12. The treatment may need to be repeated for the effect to last; how long it lasts varies with the product and the person, and cannot be predicted precisely in advance.

More filler does not mean a better result. The condition known as ‘facial overfilled syndrome’ is associated with excessive or inappropriate use of fillers. Not only too much volume but also placement that does not suit the anatomy and the build-up of repeated treatments play a part in it. It shows up as a distorted shape when the face is at rest and as unnatural facial movements; the main approach is to reduce the risk of it developing in the first place.

Nasolabial fold filler is not a substitute for a surgical facelift. Which path makes sense for you — filler, another method or none — is decided by the assessment at your consultation and by your own decision.

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How It Differs from Collagen Stimulators and Permanent Fillers

The treatment described here is hyaluronic acid filler. Collagen stimulators (substances intended to stimulate the skin’s own collagen production), such as calcium hydroxylapatite (CaHA) and poly-L-lactic acid (PLLA), are also used in the nasolabial area. These are a different class of filler; you can read about their own limits and risks, and the areas where they are not recommended, on the Liquid Facelift with Collagen Stimulators page.

Data comparing these types of filler are limited. In a network meta-analysis pooling thirteen randomised trials that compared different fillers in the nasolabial fold, fold severity scores at month 6 were lower in the PLLA group than in the hyaluronic acid group. The researchers assessed hyaluronic acid as a safe filler for this area and PLLA as a promising option. However, this result rests on a single analysis, and analyses of this kind include indirect comparisons as well as direct ones.

The main difference lies in reversibility. A review of filler complications that cause permanent damage lists the permanence of the filler, alongside the injection site and technique, among the main factors that determine permanent damage. It states that hyaluronic acid fillers continue to be preferred because they can be reversed, whereas permanent fillers increase the risk of long-term complications.

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Blood Vessels in This Area

The nasolabial area is one of the facial areas that need the most care during filler treatments because of its blood vessels. The facial artery and its upward continuation, the angular artery, run close to the fold; the course of these arteries varies markedly from person to person.

In a study that examined sixty cadaver specimens, branches of the facial artery were found near the fold in 93.3% of specimens. The artery crossed the fold in 33.9% of cases and ran upwards within 5 mm of the fold in 42.9%. In 30% of specimens, branches of the artery turning towards the under-eye area were found.

In another study using computed tomography, about 90% of nasolabial grooves (folds) had a single arterial trunk, and some had two or three trunks. In all the cases examined, the angular artery ran along the outer side of the groove at varying depths; with increasing age, the depth and the sideways distance between the artery and the groove decreased significantly. The findings of these studies, carried out with different methods and in different populations, do not match; this shows that there is no single safe map.

In a three-dimensional cadaver study, the course of the artery relative to the fold was divided into three types; in the most common type (83.7%), the facial artery continued as the angular artery. Another cadaver study found that, at the level of the side of the nose, the facial artery, the lateral nasal artery and the infraorbital (under-eye) artery run close to the fold. The arterial connections in this area link the two main arterial systems of the head, the internal and external carotid systems; researchers have described these connections as possible sources of serious complications.

At the clinic, the doctor chooses a needle or a cannula (a fine tube with a blunt tip) for each person, according to the treatment area and the anatomy. The percentages above come from cadaver and imaging studies; they do not show in advance how a particular person’s blood vessels run. The aim of this information is not to put you off but to explain why the area needs care.

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Known Risks

The most common side effects of nasolabial fold filler are irregularities you can feel, tenderness, swelling and bruising. Research on hyaluronic acid treatments in the face shows that these effects are mostly mild and go away over time; however, rare serious complications cannot be ignored.

In the meta-analysis pooling randomised trials in this area, the most commonly reported adverse effects were lumps or irregularities you can feel (43%), tenderness (41%), swelling (34%) and bruising (29%). These rates are averages from studies that also included tissue fillers other than hyaluronic acid; they are not results from this clinic.

In an analysis that assessed nineteen randomised trials together, the rates of swelling, lumps and firmness in the nasolabial fold were significantly different from those for treatments in the mid-face, around the lips and in the lips; no significant difference was seen for pain, redness, bruising, tenderness, itching or discolouration. Studies with products containing lidocaine reported less pain during the procedure, with no change in how often adverse effects occurred.

Delayed-onset inflammatory reactions are rare, but they can appear months or even years later. In an analysis of facial treatments, their frequency was calculated as about one event for every 2,000 patients followed for one year. The median time until symptoms started was 3 months; the shortest was two weeks and the longest 12 years. Common presentations are nodules (small lumps under the skin), redness, swelling and hardening; hyaluronidase, steroids (corticosteroids) and antibiotics were used to treat them. The most serious risk, vascular occlusion (a blocked blood vessel), is described separately below; what the risks mean for you is discussed at your consultation, together with your medical history.

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Vascular Occlusion: Rare but Serious

The most serious risk of nasolabial fold filler is a disruption of the blood supply to the tissue, caused by filler entering an artery or pressing on a blood vessel from outside. It is rare; however, the nasolabial fold is one of the areas where this complication is reported most often, and early recognition determines the outcome.

In an analysis pooling fourteen studies, the nasolabial fold was reported as one of the areas most often affected by vascular occlusion after filler, along with the area between the brows and the nose, both of which have complex blood vessel anatomy. According to this analysis, timely recognition and treatment are associated with recovery, while delays of more than five days are associated with permanent damage. For blockages caused by hyaluronic acid, the first-line treatment is hyaluronidase.

In a series of 20 patients whose nose skin was on the verge of tissue death after hyaluronic acid injections in the nose and nasolabial fold, 7 patients (35%) developed tissue death through all layers of the skin; 13 patients (65%) recovered completely with combined treatment that included hyaluronidase. Of those who developed skin death, 85% were patients who sought help late and did not receive this treatment within two days of their symptoms starting. In another case, tissue loss developed on the side of the nose after a treatment in the fold, and surgery was needed to repair it.

Vision loss is one of the most serious conditions linked to filler and is very rare. A recent review of published cases reported the nose, the forehead and the area between the brows as the highest-risk areas; in 68.2% of cases with a reported visual outcome, vision did not return. The nasolabial fold is not at the top of this list; however, the arterial connections described in the blood vessel anatomy section show that the area needs care in this respect too.

The doctor’s knowledge of anatomy and precautions in injection technique are key to reducing the risk. A pull-back (aspiration) test before injection cannot reliably confirm that the needle tip is not inside a blood vessel. How you contact the clinic if you notice any symptoms is set out in the clinic’s own protocol; you should be given this information before your treatment.

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Can It Be Reversed, and What If You Have Had Filler Before?

Yes, hyaluronic acid filler can be dissolved with the enzyme hyaluronidase. This sets it apart from types of filler that cannot be reversed, and it is the basis of the approach used both for an unwanted appearance and in an emergency such as vascular occlusion. Hyaluronidase is kept at the clinic.

According to a review of the use of hyaluronidase, the enzyme can reverse complications of hyaluronic acid fillers; controlled data on this are limited, but clinical experience is growing. Non-urgent situations — bluish discolouration under the skin (the Tyndall effect), non-inflammatory nodules, and allergic or hypersensitivity reactions — are assessed separately from emergencies such as vascular occlusion and vision loss. In an emergency, treatment needs to start without delay.

If you have had filler in the area before, the first question is not a new treatment but what the existing filler is. The review of complications that cause permanent damage also lists the permanence of the filler as one of the main factors that determine permanent damage. For filler done elsewhere in the past, the first step is to ask about the type of filler, when it was done and which area was treated; filler of unknown type, or filler that cannot be confirmed to be hyaluronic acid, is not dissolved straight away. If you have any record of the previous treatment, it helps to bring it to your consultation.

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