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A comprehensive narrative review on lip filler techniques with practical tips for optimum outcomes
*Corresponding author: Jaishree Sharad, Department of Dermatology, Skinfinitii Aesthetic Skin and Laser Clinic, Mumbai, Maharashtra, India. jaishree19@gmail.com
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Received: ,
Accepted: ,
How to cite this article: Sharad J, Singh S. A comprehensive narrative review on lip filler techniques with practical tips for optimum outcomes. J Cutan Aesthet Surg. doi: 10.25259/JCAS_90_2025
Abstract
Introduction:
Lips are widely regarded as the most esthetically significant feature of the face, particularly in females. With age, they tend to lose volume and definition as bone resorption, fat loss, and muscle thinning cause the upper lip to roll inward. Hyaluronic acid injections have become a popular intervention to restore volume, enhance shape, correct asymmetries, and define the lip margin and pout. Various injection techniques cater to different esthetic and functional concerns. By analyzing the latest literature, this review highlights best practices for achieving optimal outcomes in patients seeking lip fillers for indications such as volume loss, asymmetry, and perioral wrinkles. Additionally, it examines strategies to mitigate common adverse effects, including bruising, swelling, and overfilling.
Aim:
This study aims to provide a narrative review of the published medical literature on various techniques used in patients to inject lip fillers for different indications, with minimal side effects and natural-looking results.
Material and Methods:
The literature research considered published journal articles (clinical trials or scientific reviews). Studies were identified by searching electronic databases (MEDLINE and PubMed) and reviewing the reference lists of relevant articles. Only articles available in English were considered for this review.
Results:
Lip augmentation has gained popularity for enhancing esthetics and boosting confidence, focusing on three key areas: the vermilion border, the red lip region, and the philtrum. Fillers are injected to add volume, but excessive use can result in an unnatural appearance and restrict lip movement. Techniques such as needle injections offer precise filler placement, while blunt-ended cannulas are preferred for safer, deeper injections. Filler migration, particularly in the upper lip, can occur due to muscle movement, the type of filler used, poor technique, or external factors. Techniques such as the Paris and Russian Lip methods carry a higher risk of migration and unnatural results . Gradual augmentation with smaller amounts of filler is recommended for individuals with thin lips or those who are older, to ensure natural-looking outcomes. Proper technique, filler choice, and post-procedural care are essential for optimal, safe, and long-lasting results.
Conclusion:
This review highlights the significance of technique, filler choice, and patient anatomy in achieving optimal lip augmentation outcomes with minimal side effects. Advances in filler formulations and personalized approaches have improved stability, reduced migration risks, and enhanced patient satisfaction, while post-procedure care and education remain crucial for safe outcomes.
Keywords
Fillers
Lip enhancement
Lip filler
Lip rejuvenation
Review
INTRODUCTION
Lips are widely regarded as the most esthetically significant feature of the face, particularly in females. With age, they tend to lose volume and definition as bone resorption, fat loss, and muscle thinning causes the upper lip to roll inward. Hyaluronic acid (HA) injections have become a popular intervention to restore volume, enhance shape, correct asymmetries, and define the lip margin and pout. Various injection techniques cater to different esthetic and functional concerns. By analyzing the latest literature, this review highlights best practices for achieving optimal outcomes in patients seeking lip fillers for indications such as volume loss, asymmetry, and perioral wrinkles. Additionally, it examines strategies to mitigate common adverse effects, including bruising, swelling, and overfilling.
Patient demographics and esthetic goals for lip fillers
Lip augmentation procedures vary widely depending on the patient’s age, ethnicity, and specific esthetic goals. Understanding patient demographics and individual esthetic goals significantly influences treatment planning and harmonious results. In Caucasian patients, lip filler interventions are commonly categorized into four groups: young lips seeking volumization, young lips requiring reshaping, senescent lips needing rejuvenation, and senescent lips that require more extensive rebuilding to restore lost volume and definition.
For Asian patients, the esthetic considerations differ. Young patients with well-proportioned lips may seek enhancement for subtle improvements, while those with disproportionate features may request correction at any age. In addition, some individuals may have well-proportioned lips but experience dryness or wrinkling, while aging patients primarily seek rejuvenation to address volume loss and lip contour changes.
In India, specific trends and motivations are emerging among different patient groups. Young women (18–35 years old), often influenced by social media and Bollywood celebrities, seek subtle volumization, definition of the Cupid’s bow, and a vermilion border, aiming to achieve a hydrated, fuller appearance. Mature women (aged 35 and above) typically focus on rejuvenation, aiming to restore lost volume, enhance vermilion show, and correct perioral wrinkles.
Male patients typically request subtle refinements to enhance lip symmetry and hydration, prioritizing a well-defined, masculine appearance with minimal fullness. In contrast, gender-diverse patients, particularly trans feminine individuals, often desire fuller lips with enhanced definition and projection, while trans masculine patients generally seek subtle augmentation to preserve proportionality without excessive roundness.
Lip anatomy and esthetic considerations
The lips, extending from the base of the nose to the upper chin, function as a distinct anatomical unit composed of both skin and mucosa. The defining border, known as the white roll or vermilion border, outlines the transition between the skin and the vermilion, which forms the body of the lip. The vermilion itself is divided into the dry and wet lip. The philtral columns, two paramedian elevations extending from the base of the nasal septum to the tubercle, shape the characteristic Cupid’s bow. The philtrum, the central groove between the philtral columns, further defines the upper lip’s esthetic. The upper lip features three tubercles, while the lower lip has two tubercles. The lower lip meets the upper lip at the lateral commissures, the angular junctions at the corners of the mouth. Below the lower lip lies the labiomental crease, a defining contour that separates the lip from the chin [Figure 1].1
- Anatomical landmarks of the lips (1- Philtral column, 2 - philtral groove, 3 - cupid’s peak, 4 - cupid’s bow, 5- vermillion border or white roll, 6 - vermillion, 7 - tubercles, 8 - wet mucosa, 9 - oral commissure, 10 - labiomental crease).
An ideal lip aligns parallel to an imaginary line drawn between the pupils when the head is in a natural position. The upper lip typically measures 18–20 mm from the base of the nose, while the lower lip lies 36–40 mm from the chin. From a profile view, lip harmony is evaluated using Steiner’s line–a reference line from the nasal columella to the chin– where ideally both lips lightly touch the line. The nasolabial angle, crucial for facial balance, should range between 85° and 105°. A distinctive feature of the upper lip is the Glogau-Klein point, a subtle elevation at the transition from glabrous skin to mucosa at the Cupid’s bow peak. In terms of proportionality, while a youthful and feminine lower lip is fuller, the upper lip should project 1–2 mm more in profile. Racial and ethnic variations influence lip proportions, with an upper-to-lower lip ratio of approximately 1:1.6 in Caucasians (reflecting the golden ratio) and 1:1 in Asians [Figure 2a and b].2
- Aesthetic lips (a-Nasolabial angle, b-Steiner’s line).
Anatomic alterations of the aging lip
Aging induces progressive anatomical and morphological changes in the lips, affecting both their esthetic and functional attributes. The philtral columns flatten, diminishing the vertical grooves between the nose and upper lip, while the Cupid’s bow loses its characteristic definition. The vermilion border blurs, and the upper lip elongates, leading to reduced vermilion show and a flattened appearance. Soft tissue volume depletion results in thinner, less plump lips, with reduced upper lip projection contributing to a flatter facial profile. The oral commissures, forming marionette lines, often impart a sad or tired expression. Additionally, the lips become more vertically oriented and recede inward, thereby diminishing their prominence and fullness. Perioral rhytides or “lipstick lines” develop around the mouth due to repetitive muscle activity and loss of skin elasticity [Figure 3].
- Aging lips (thinning of upper lips, peri oral lines, loss of philtral columns).
Understanding these age-related alterations is critical for guiding effective esthetic interventions aimed at restoring youthful lip characteristics.3
A precise understanding of the vascular structures within the lips is crucial for ensuring the safety of esthetic procedures, particularly in avoiding vascular complications. The lip is supplied by the superior and inferior labial arteries (SLA, ILA), which are branches of the facial artery. Cotofana et al. conducted an ultrasound-guided study of the labial arteries and found that both the SLA and ILA predominantly reside in the submucosal plane (58.5%), with lesser contributions from the intramuscular (36.2%) and subcutaneous (5.3%) planes.4 The SLA was positioned at an average depth of 5.6 ± 0.13 mm in the upper lip, and the ILA at 5.2 ± 0.14 mm in the lower lip. Importantly, the labial arteries were consistently found within the red lip along the midline in all participants, highlighting the critical importance of precise anatomical knowledge for safe esthetic interventions.4
Knowledge of the lip and perioral muscles helps ensure the accurate placement of filler and maintain the natural movement and function of the lips. This understanding is key to preventing unwanted outcomes, such as asymmetry or loss of natural expression.
Pre-injection considerations
Clinical assessment of the lips before filler injection
A thorough evaluation of the lips, both at rest and in motion, is essential before administering fillers to ensure precise esthetic and functional outcomes. Key aspects include lip architecture–assessing the vermilion border, Cupid’s bow, philtral columns, volume, upper-to-lower lip ratio, and upper lip projection, which ideally should extend 2 mm anterior to the lower lip. Muscle activity must be evaluated by observing perioral muscle contraction, the presence of perioral rhytids, marionette lines, and nasolabial folds. Dental assessment is crucial, as the anterior inclination of the maxillary teeth can limit upper lip augmentation. Aging-related alveolar bone and enamel loss also contribute to lip inversion and volume loss. Symmetry at rest and during smiling must also be examined. Smile dynamics–including commissural, canine, full denture, and gingival (gummy) smiles–should be analyzed, as different muscle patterns influence natural expressions. Identifying the smile type enables clinicians to tailor filler techniques to enhance esthetics while preserving natural, dynamic facial movements.5
Anesthesia and pain management for lip filler procedure
Topical anesthesia, like prilocaine–lidocaine formulations, effectively alleviates discomfort in sensitive lip areas. Additional techniques include vibratory devices, ice application for sensory distraction, and talkesthesia to reduce anxiety. Although nerve blocks offer profound anesthesia, they can temporarily affect lip movement and smile dynamics, which can complicate symmetry and filler placement assessment.
Injectable materials
HA remains the most widely used material for lip augmentation. HA is a naturally occurring substance in the body that helps maintain skin hydration and elasticity. HA-based fillers have gained popularity due to their ability to provide immediate, visible results, their natural feel, and their reversibility. These fillers come in various formulations, each designed to provide different textures, viscosities, and longevity. For instance, more viscous (mid G prime) formulations are ideal for volumizing, while softer products (low G prime) are better suited for fine lines and defining the lip borders.
The use of calcium hydroxylapatite and poly-L-lactic acid in the lips is associated with an increased risk of nodules, asymmetry, overcorrection, and vascular compromise, making them less suitable for lip augmentation. Autologous fat transfer, while offering longer-lasting results, carries unpredictable resorption rates and a higher risk of contour irregularities. Given the lips’ delicate anatomy, HA fillers remain the preferred and safest option.6
Injection techniques to minimize complications
A gradual injection technique, using small increments, helps reduce the risk of overfilling, asymmetry, and nodularity, ensuring a more natural and balanced outcome. Additionally, using fine-gauge needles and 25-gauge blunt-tipped cannulas minimizes tissue trauma, thereby reducing the likelihood of bruising, swelling, and vascular complications.
Post-treatment recommendations
The application of cold compresses immediately after the procedure can help reduce swelling and discomfort. Patients are advised to avoid activities that may worsen swelling or bruising, such as intense exercise and alcohol consumption, for at least 24 h post-treatment. In addition, lip balms and lipsticks should be avoided for at least 12 h following the procedure to minimize the risk of infection. Patients should also refrain from activities such as lip pursing, lip licking, and kissing, as these movements can put unnecessary pressure on the treated area, potentially affecting the results and increasing the risk of complications.
MATERIALS AND METHODS
Our search strategy for this narrative review included search terms such as lip filler techniques, HA injections, lip augmentation, perioral rejuvenation, esthetic lip enhancement, lip anatomy, lip aging, injection methods for lips, complications of lip fillers, patient satisfaction in lip augmentation in databases such as PubMed, Embase, and Google Scholar from 2008 to 2024.
Inclusion criteria: Original research articles, clinical studies, systematic reviews, and expert opinion pieces focusing on lip filler techniques in detail, outcomes, and complications in human subjects and articles available in English. Exclusion criteria included animal studies and articles that focused solely on other facial areas without significant lip-related content. To improve the search strategy and methodology, Mendeley reference management software was utilized to detect and flag potential duplicates automatically. We initially identified 60 articles based on our keywords, out of which 24 were rejected because their abstracts did not meet our inclusion criteria, and 6 were excluded during full-text screening due to their study design.
These criteria ensure a comprehensive review of current clinical practices and research in lip augmentation, while maintaining focus on human applications and accessibility to the intended audience.
Information was synthesized thematically, organizing findings into key areas such as lip anatomy, aging effects, injection techniques, filler materials, patient assessment, and complication management. Within each theme, data were further analyzed to compare different approaches, highlight evolving trends, and identify best practices based on reported outcomes and expert recommendations.
RESULTS
Injection techniques for lip enhancement
Cannula technique can be placed after the 4 techniques as illustrated in Figure 4. The technique used in lip filler injections significantly impacts the outcome, influencing both the esthetic results and the likelihood of side effects. Various methods have been developed to achieve smooth, natural-looking lips, with some of the most effective techniques outlined below:
- Basic Injection techniques. The black arrow represents the direction of withdrawing the needle/cannula while depositing micro-depots of the fillers.
Linear retrograde technique
In this method, the filler is injected in a continuous line while the needle is gradually withdrawn. This technique ensures even distribution, making it particularly effective for enhancing lip volume and creating a smooth, balanced appearance.
Serial puncture method
The serial puncture technique involves a series of small injection points along the lip border and within the lip tissue. Small amounts of filler are deposited at each site, enabling precise contouring, volume restoration, and definition of the vermilion border. This method offers greater control and is ideal for achieving subtle, well-balanced results.
Cannula technique
Using a blunt-tipped cannula instead of a traditional needle has become increasingly popular due to its ability to minimize trauma, bruising, and vascular complications. The cannula smoothly navigates through the tissue, enabling precise filler placement with reduced discomfort. This technique is particularly beneficial for volumizing the lips while maintaining a soft, natural finish.
Cross-hatching technique
The filler is injected in perpendicular lines intersecting to form a grid.
Fanning technique
The cross-hatching or fanning technique involves distributing the filler in a pattern that radiates out from a central point. This technique helps to create a more natural flow and integration of the filler within the lips, particularly for improving lip volume without over-exaggeration [Figure 4].7
Injection zones
Dr de Maio made MD Codes which divides the lips into eight subunits, each corresponding to a specific anatomical and esthetic structure, making it easy to reference and use as a system for outlining lip injection protocols as mentioned in Table 1.8 Jacono divided the lips into fifteen different injection zones, eight in upper lip and seven in the lower lip as mentioned in Figure 5a and b.9
| Code | Injection area |
|---|---|
| Lp1 | Vermilion |
| Lp2 | Cupid’s bow |
| Lp3 | Lip border |
| Lp4 | Medial tubercles |
| Lp5 | Lateral tubercles |
| Lp6 | Oral commissure |
| Lp7 | Philtral columns |
| Lp8 | Perioral lines |
MD Code: Medical code
- (a and b) The fifteen different injection zones of the lips according to Jacono.
Injection techniques
Peng and Peng lip reshaping
Peng and Peng categorized Asian lips into four distinct types and applied the MD codes to guide filler injection techniques as described in Table 2. Their study concluded that classifying Asian patients into these four lip phenotypes enables physicians to identify the primary esthetic concern, ensuring precise corrections while minimizing the risk of over-injection or excessive lip augmentation [Figure 6a-c].10
| Lip type | MD codes injected |
|---|---|
| Type 1 | Lp4, Lp5 |
| Type 2 | Lp1, Lp4, Lp5, Lp6 |
| Type 3 | Lp1 |
| Type 4 | Lp1-8 |
- (a) Illustration of Peng’s technique; images of before lip filler (b) and after lip filler (c), using Peng’s technique. Peng’s reshaping technique using MD Codes lip injection areas: blue circle-Lp1; green circle-Lp4,5 ; green arrow-Lp3,6,7; green dots-Lp8.
Four-point injection technique for lip augmentation
In this technique, the lips are divided into right and left halves using an imaginary vertical midline passing through the center of the Cupid’s bow. A 25G needle is used to create four entry points–5 mm above the vermilion border of the upper lip and 5 mm below the vermilion border of the lower lip. A 27G, 25 mm cannula is then introduced to administer 24 mg/mL HA combined with 0.3% lidocaine through a submucosal fanning technique. Small boluses ranging from 0.1 to 0.4 mL are deposited, followed by gentle massage to ensure even distribution of the filler. With this approach, 90% of subjects reported satisfaction or high satisfaction with their lip enhancement results. Minimal discomfort and mild erythema were noted at the needle entry sites, but no cases of bruising, bleeding, significant swelling, pruritus, infection, necrosis, skin discoloration, nodules, or foreign body granuloma were observed [Figure 7].11
- Illustration of the four point technique. Blue line: imaginary vertical midline; Black circles: entry points; black lines: fanning technique of injecting filler.
Mannino and Lipner’s technique for lip augmentation
This structured approach provides precise lip augmentation while maintaining a natural esthetic outcome.
Lip margin enhancement
The border injection technique focuses on adding definition by injecting filler along the vermilion border. The marginal injection technique involves injecting at the dry–wet junction (or skin-mucosa junction), extending toward the upper and lower lip regions. The eversion technique involves placing filler in the submucosal plane within the oral vestibule to achieve subtle lip eversion, thereby enhancing volume and projection.
Labial tubercle augmentation
For defining the midline of the upper lip, fanning injections along the vermilion border at the Cupid’s bow are performed to accentuate the labial tubercle and create a refined, balanced shape.
Lip volumization
To enhance lip volume, serial transverse or longitudinal injections are used, applied to both the upper and lower lips. The towering technique, which involves deep, perpendicular injections along the vermilion lines, adds structure and projection to the lips, creating a more defined contour [Figure 8].12
- Illustration of the Mannino and Lipner technique. Blue line: imaginary vertical midline. Blue arrow: lip volumization; White arrow: labial tubercle augmentation; Yellow arrow: injecting at dry-wet junction.
Surek et al. described a no-touch technique for lip enhancement that does not violate the mucosa. They divided the lip into 3 areas:13
-
Shape and definition of the “white roll,” (the junction between the skin and dry vermilion) which determines lip profile [Figure 9]
Figure 9:- Images of before lip filler and after lip filler, using Surek’s technique to achieve shape and definition of the “white roll.”
The vermilion itself between the white and red rolls, which determines lip projection
The red roll, which is the invagination of the orbicularis oculi muscle and wet mucosa, which correlates to lip augmentation.
The injection entry point is located 5 mm lateral to the oral commissure, allowing for retrograde filler deposition via needle or cannula without breaching the labial mucosa. It allows injectors to mold the lip without puncturing the mucosa, which reduces edema, ecchymosis, postoperative discomfort, and the “bee-stung” effect. Edema or ecchymosis within the mucosa can distort lip shape during injection, potentially affecting clinical judgment. In addition, mucosal trauma may accelerate filler resorption due to inflammation. By restricting entry to the less contaminated cutaneous surface, this technique may lower the risk of infection by oral flora as the skin is less contaminated than the oral mucosa.13
Sarnoff et al. recommend a six-step technique to achieve a natural look. They used approximately 12 injections of around 0.1 cc HA each to the upper and lower lips in the following stages:14
Creating the philtrum columns
Creating the Cupid’s bow
Defining the vermilion-cutaneous junction of the upper lip
Creating lower lip tubercles
Supporting the oral commissures, and
Filling the upper part of the nasolabial folds.
Sarnoff et al. are of the opinion that there is no single prescription for a “perfect“ lip, but these six steps can be used as a basic template for achieving a natural look. The study also notes that the approach to lip augmentation should take into account the patient’s facial features, age, and ethnic background [Figure 10].14
- Before and after lip filler using Sarnoff ’s six-step technique.
Greene compared different approaches for filler techniques in young versus matured lips: For younger lips, a precise definition of the vermilion border is recommended before volumization. A total of 0.2 to 0.4 mL of filler can be placed along the mucosal side of the vermilion border using a slow threading technique. Care should be taken to avoid posterior placement near the oral mucosa, as this may lead to excessive anterior lip projection, contributing to an unnatural, “duck lip” deformity. Instead, filler should be deposited within the dry vermilion, facilitating a more natural vertical rotation–upward for the upper lip and downward for the lower lip–enhancing the visibility of the vermilion without excessive protrusion.
For mature lips, a conservative approach is recommended, utilizing lower filler volumes to preserve natural proportions. To restore definition, <0.25 mL can be carefully injected along the vermilion border. Filler placed within the cutaneous lip softens harsh shadows, ensuring a smoother transition between the lip and surrounding skin. A fanning technique with minimal, evenly distributed filler helps improve lip texture while preventing lumps or visible product [Figure 11].
- Before and after lip filler using Greene’s technique for mature lips.
Treatment of perioral rhytids can involve linear threading, fanning, or serial microdroplet injections. For philtral column enhancement, injections should be performed at a 15–20° angle, just medial to the natural philtral ridge, with a slight increase in product placement inferiorly to maintain natural contours. The oral commissures can be subtly lifted by injecting filler into the modiolus of the orbicularis oris, just lateral to the commissure.15
Sundaram, in her article on lip and perioral frame enhancement in skin of color, examines volume loss in the perioral region, categorizing it into immediate and peripheral perioral frames. The immediate perioral frame refers to the area directly surrounding the vermilion lips, including the cutaneous upper lip (along with the philtrum), the corners of the mouth, and the cutaneous lower lip up to the labiomental crease. In contrast, the peripheral perioral frame encompasses all regions where filler injections can provide perioral lifting. This includes the area beside the mouth corners, extending across the lower midface and lower face to the preauricular region and mandibular angle, as well as the supramedial midface just above the alar-facial groove.
Sundaram suggests that classifying the perioral frame into immediate and peripheral zones enhances the accuracy of volume loss assessment in the lower face. A two-layer technique was found to be particularly effective – deeply injected, large-particle non-animal stabilized HA (NASHA) is used for volumization and lifting, while a more superficial application of small-particle NASHA shapes the lips. This approach yields a soft, natural texture immediately after injection, providing precise contouring and exceptional stability with minimal or no swelling.
Furthermore, a slow, steady anterograde injection of free-flowing NASHA fillers minimizes tissue trauma and inflammation, thereby reducing the risk of post-inflammatory hyperpigmentation, a common concern in skin of color.16
Dr Steven Harris’s nonsurgical lip lift (NLL)
Dr. Harris coined the P’s and S’s of lip assessment, the P’s being proportion, projection, position, philtrum, and perioral area, and the S’s being shape, symmetry, size, surface, and smile. It is known that aging shrinks the facial skeleton, and the resultant inward rotation leads to the weighing down of the unsupported soft tissues on the lips. As a result, the lips collapse due to the loss of their intrinsic structural support. To counteract this, a holistic facial reshaping approach is recommended, as it indirectly enhances lip esthetics by restoring the ideal facial proportions. He introduced the following concepts:
H-lines (Harris planes, H-planes): These help identify the ideal positioning of the tubercles
H-curves (Harris curves): These define the optimal curvature of the lower lip in relation to the chin [Figure 12a and b].
- (a and b) Dr Steve Harris’ tubercles, H-lines and H-curves. Red circle- tubercles; black & white lines- H lines; green curved line- H curves.
The NLL technique in classic form involves tens steps with no more than 0.05 mL of filler required per step: lateral tubercles (steps 1,5,6,10) linear threads (steps 2,4,7,9) with placement of filler in the central tubercle (steps 4 and 9) and curved threads (steps 3 and 8) [Figure 13].
- The nonsurgical lip lift technique. Black circle: tubercles; blue arrows: linear thread directions.
Furthermore, to maximize safety, this technique recommends using small amounts of product that are placed gently, slowly, and superficially, at a depth of no more than 1–2 mm below the surface.17
Russian/tenting
The “Bratz doll” (BD) or ‘Russian lip’ style has become a highly sought-after esthetic trend, inspired by the exaggerated features of the popular BDs. This style is characterized by an increased vermilion height, reduced angular measurements, and a greater distance between the midline and the oral commissure. Traditionally, achieving this look involves multiple vertical injections of a large volume of HA, which carries risks such as bruising and vascular complications.
A 2024 study involving thirty volunteers introduced a blunt cannula technique to enhance the lips using only 0.4 mL of HA per side. The results were highly satisfactory (8.5/10), and none of the participants experienced bruising, demonstrating the technique’s effectiveness18 [Figure 14].
- Illustration of the Russian lip technique. Red dotted line-vertical line dropped down from the medial canthus of eye, blue arrow-vertical injections.
French kiss technique (FKT)
The FKT technique involves injecting a small volume of low-cohesivity HA filler using a short needle at low pressure to prevent bumps. This is followed by gentle massaging to distribute the filler along the major axis evenly. The procedure is repeated at pre-marked points on the upper and lower lips, with 0.1–0.2 mL of the solution injected per point.
In a proof-of-concept study involving 120 Caucasian patients (114 women, aged 34–64, mean age 42), the technique resulted in a natural lip plumping effect. Ninety percent of participants reported improved or significantly improved results. No major complications were observed, and 90% of patients rated their pain as low (Level 2)19 [Figure 15].
- Illustration of the French Kiss technique. Blue solid lines-vertical lines dropped down bilaterally from angles of the lip and centre of the cupid’s bow; blue dotted lines- divides one half of the lip into 3 equal sections vertically.
Buhsem O needle and cannula technique
In a 2023 clinical study, Buhsem systematically evaluated the role of injection vector direction and needle versus cannula on the esthetic outcomes of HA lip filler treatments. The investigators divided 108 patients into four groups, each receiving a distinct technique: top-to-bottom needle injection, bottom-to-top needle injection, lateral-tomedial needle injection, and lateral-to-medial cannula injection. The primary endpoints included the degree of lip eversion, filler migration, and overall patient satisfaction. Notably, the top-to-bottom needle vector (Group 1) not only yielded the highest satisfaction and best esthetic eversion but also demonstrated improved control over filler migration20[Figure 16].
- Illustration of the Buhsem O technique.
The 4.3 technique: Structured point-based augmentation for volume and definition
The procedure uses a combined retrograde linear and vertical needle injection technique with HA-based filler (Art Filler Lips with 0.3% Lidocaine) at four points on the upper lip and three on the lower lip. A total of 0.7 mL is injected, with 0.4 mL for the upper lip and 0.3 mL for the lower lip, aiming for volume and contour definition . The filler is injected carefully to avoid placement that is either too superficial or too deep, and additional touch-ups are performed as needed.21
DISCUSSION
Lip augmentation has become increasingly popular, as full lips are associated with youth and beauty, which can boost self-esteem and confidence. Lip rejuvenation focuses on four main areas: the vermilion border, the red lip region, the cupid’s bow and the philtrum. Optimal esthetic outcomes in lip augmentation are achieved through precise filler placement that respects the intricate anatomy of the lips. Injecting just beneath the white roll enhances the definition of the lip margin, accentuating features such as the Cupid’s bow and philtral columns, which are essential for a youthful appearance. Augmenting the vermilion border adds volume, contributing to fuller lips. Targeting the area between the wet and dry parts of the lip improves projection, enhancing the overall lip profile.
Needles are generally preferred for superficial lip injections, especially along the vermilion border, where sharp precision is required for contour definition. Their ability to deliver product accurately into the superficial dermis makes them ideal for enhancing the Cupid’s bow, lip border, and defining the philtral columns.22 Superficial placement of filler is considered safe both with a needle or a 25 gauge blunt cannula. The use of blunt cannulas for intramuscular or submucosal placement of fillers to achieve uniform distribution and volumization of the lips is becoming increasingly popular. However, overcorrection in these deeper planes can result in an unnatural appearance and may impair natural lip mobility. Blandford et al. demonstrated in a cadaveric study that microcannula injections into the upper lip vermilion border resulted in more homogeneous filler deposition in the intramuscular zone, suggesting a potential advantage in volumization and minimizing product irregularities.23 However, improper use of small cannulas or excessive injection force can still cause vascular damage. A tailored approach is often ideal–using needles for contouring and cannulas for volumizing–depending on the treatment zone, lip anatomy, and clinical objective.24-27
For patients with thin lips or those of advanced age, a gradual approach to augmentation is advisable. Administering 0.5 mL of filler per session at intervals of 4–8 weeks allows for controlled enhancement, minimizing potential complications and ensuring natural results.3
Filler migration, especially in the upper lip, is also common due to the movement of the orbicularis oris, which causes stretching, compression, and shear forces leading to displacement of the filler, especially when large volumes are injected or when fillers are injected frequently. Poor injection technique, excessive massaging after filler injection, and lymphatic spread can also cause filler migration. Certain techniques, such as the Paris and Russian Lip methods, have been criticized for their increased risk of filler migration into the cutaneous lip. These techniques often involve multiple vertical injections or excessive placement along the vermilion border, disrupting natural anatomical barriers and leading to unintended filler spread over time. Some experts argue that such methods may create an initial dramatic effect but compromise long-term stability, increasing the likelihood of a ledge-like appearance or “duck lips.” Instead, more conservative approaches that respect the natural lip structure are recommended to minimize migration and maintain a natural esthetic look.
Multiple techniques for lip filler injections have been described in the literature, and clinicians may adopt the approach best suited to their expertise and patient needs. However, the fundamental principles remain constant: respecting anatomical boundaries, using minimal product volumes, injecting slowly, and employing techniques that minimize the risk of complications.
CONCLUSION
In summary, this review highlights the diverse techniques and considerations in lip filler injections aimed at achieving optimal esthetic outcomes with minimal side effects. The choice of technique — whether needle or cannula, and the direction and depth of injection — plays a critical role in the final result, influencing both filler migration and patient satisfaction. Advances in filler formulations, such as high-viscosity and cohesive products, have further enhanced the stability and longevity of lip augmentations, reducing the risk of complications like migration and asymmetry. Understanding the patient’s anatomy, as well as the dynamic nature of lip movements, is essential in tailoring the approach for each individual. In addition, post-procedure care and patient education remain key factors in minimizing adverse effects, ensuring that the esthetic goals are met while maintaining the safety and satisfaction of the patient. As techniques continue to evolve, ongoing research remains crucial in refining these methods, optimizing results, and minimizing risks, ultimately leading to more natural and harmonious outcomes in lip enhancement procedures.
Authors’ contributions:
Jaishree Sharad : Concept, data acquisition, review. Shreya Singh: Data acquisition, manuscript preparation.
Ethical approval:
Institutional Review Board approval is not required.
Declaration of patient consent:
Patient’s consent not required as there are no patients in this study.
Conflicts of interest:
There are no conflicts of interest.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation:
The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.
Financial support and sponsorship: Nil.
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