Summary:
Neck injections of botulinum toxin A (BTX-A) are an effective, minimally invasive approach to improve lower face sagging, especially in Asian populations. However, cases of worsened “double chin” have been observed postinjection, likely due to the platysma muscle type and limited anterior neck injection range, which may result in compensatory platysma contraction. Five female patients who developed aggravated double chin after BTX-A injections in the lower jaw and neck were treated with microneedle BTX-A injections (10–20 U in 3–4 rows with 0.5–1 cm between points). Effective submental lifting and double chin improvement were observed within 5–10 days, with no reports of voice changes or dysphagia. This microneedle BTX-A injection technique provides a safe, effective solution for enhancing the anterior neck region and can serve as an important adjunct to lower face antiaging treatments.
Takeaways
Question: How can the aggravated “double chin” after botulinum toxin A (BTX-A) neck injection for lower face sagging be solved?
Findings: Five patients who received BTX-A injections in the lower jaw and neck region for lower face sagging developed worsening of the double chin. All patients showed effective lifting of the submental area and improvement in the appearance of the double chin about 7 days after treatment, with no reported cases of complications.
Meaning: Microneedle injections of BTX-A in the anterior neck region are a safe, convenient, and effective intervention to improve the appearance of the double chin after BTX-A injections in the lower jaw.
INTRODUCTION
Botulinum toxin A (BTX-A) is popular for facial rejuvenation. The platysma muscle, a thin neck muscle, contributes to “double chin” formation as it droops with age. Injecting BTX-A in the platysma can lift the lower face and enhance the jawline, but deep or excessive injections can lead to complications such as voice changes and dysphagia.1–3 To address worsening double chin postinjection due to insufficient coverage and compensatory muscle contraction, microneedle BTX-A injections were used in the submental platysma.
PATIENTS AND METHODS
Participants
From January 2020 to December 2023, 5 female patients (22–55 y of age, average 41 y) received BTX-A injections in the lower jawline and neck region for lower face sagging at other hospitals and developed worsening of the double chin. These patients sought nonsurgical interventions to improve the appearance of the lower face because of their concern for health and appearance. Before treatment, we took facial photographs (side view) of each patient, excluded contraindications, and informed the patients of posttreatment precautions. Written informed consent was obtained from all the patients.
Methods
The submental area was evaluated for fullness, laxity, and muscle activity. After marking and disinfecting the area, microneedles (FITTER, 34G4A, Yangzhong Chengmei Medical Instruments Co., Ltd., China) were used to inject BTX-A (Botox, 100 U per bottle, Allergan Pharmaceuticals, Ireland) diluted in 2.5 mL of saline. Each microneedle had 4 short 34G needles, each 1.2 mm in length. The injections were administered in the submental midline region, with a total dose of 10–20 and 0.5–1 U per injection site. Three to 4 rows of injection sites were set up in an alternating arrangement with 0.5–1 cm spacing between sites, covering the entire injection area. Aftercare instructions were provided, and results were assessed at 2 and 12 weeks through photographs, patient satisfaction, and safety evaluations.
RESULTS
Over time, the patients reported an improvement in their submental contour. All patients showed effective lifting of the submental area and improvement in the appearance of the double chin 5–10 days (average 7.4 d) after receiving microneedle injections of BTX-A in the platysma muscle. The results of the patient satisfaction survey questionnaire at 12 weeks follow-up showed that 3 patients were very satisfied (60%), 1 was satisfied (20%), 1 was basically satisfied (20%), and no patient was dissatisfied (Figs. 1, 2).
Fig. 1.
Case 3: a 55-year-old woman developed an aggravated double chin 11 days after BTX-A injection for lower facial ptosis. After microneedling with BTX-A (15 points, 1 U each) in the chin, the wheal subsided in 3 hours. Improvement was noted 10 days later, with sustained results at 12 weeks. A, Before. B, 2 weeks after.
Fig. 2.
Case 4: a 22-year-old woman developed an aggravated double chin 1 week after BTX-A injection for jawline contouring. After microneedling with BTX-A (15 points, 1 U each), the wheal subsided in 1 hour. Improvement was seen 7 days later, with sustained results at 12 weeks. A, Before. B, 2 weeks after.
One patient complained of significant pain, which recovered after injection; 1 patient developed redness and swelling, which subsided after ice application; and 1 patient developed bruising, which disappeared after 1 week. No patient developed complications such as speech impairment, dysphagia, or other adverse reactions. The good treatment effect persisted, and the improved mandibular contour was maintained for 3 months.
DISCUSSION
A double chin results from excess fat in both superficial and deeper layers around the platysma muscle, leading to a less defined jawline and aged appearance. Common treatments include neck lifts, submental liposuction, deoxycholic acid injections, cryolipolysis, BTX-A injections, and skin resurfacing.4 Minimally invasive options such as BTX-A injections are popular but require caution in the anterior neck due to risks such as voice changes and asymmetry. Submental fat has superficial and subplatysmal layers, making controlled BTX-A diffusion essential to avoid side effects. Microneedles, used for precise dosing, reduce side effects and improve double chin outcomes.
BTX-A use for lower face enhancement is increasingly popular,5 though complications are documented, such as pain, voice changes, dysphagia, and worsened double chin.6 Anatomical studies have identified 3 platysma muscle types.7 The most common variant, observed in approximately 75% of individuals, is characterized by fibers of the platysma muscle crossing to the opposite side, located 1–2 cm below the jawline. In type II, fibers interweave at the level of the thyroid cartilage, forming a sticky band covering the submental region in approximately 15% of individuals. In type III, the fibers bifurcate in the submental region but do not cross over to the opposite side. This variant is observed in approximately 10% of individuals. Additionally, research has shown anatomical variations between individuals, with some individuals having a central concentration of the platysma muscle in the midline of the neck, whereas others have a more diffuse distribution. Some fibers deviate from the midline in the upper portion of the neck, covering the submental region. Previous research has shown that 85% of the inner neck fibers are separated in the submental region.7 Furthermore, 43% of the subjects had fibers that extended more than 20 mm below the jawline. Research has shown that individuals with unseparated or mildly separated platysma muscles and those with adjacent subcutaneous tissue laxity may develop a distorted double chin after BTX-A injections.8
The most significant submental fat pad was located beneath the 2 bands of the platysma muscle. Additionally, superficial fat pads were located above the platysma muscle. When the superficial fat pad is sufficiently large, it can present as a midline bulge below the jawline.9 Generally, the presence of submental fat leads to central fullness between the noncrossing platysma and accompanying excess skin. In cases where the platysma envelops the entire submandibular region (type II), one can anticipate an approximate 100% reduction of the larger submental fat pad. However, in the absence of the submental platysma muscle (a feature of type III anatomical variation) and the presence of a fat pad, liposuction can be considered an adjunctive procedure to enhance cosmetic outcomes. The jawline and neck’s defined structure greatly influence facial attractiveness and appeal, as a sharp jawline and clear submental region are linked to youthfulness and aesthetic harmony.
CONCLUSIONS
This study reports on BTX-A microneedle injections in the platysma muscle for 5 patients who experienced worsening double chin after neck lift procedures. Using microneedles for submental injections prevented further double chin aggravation and led to significant improvement in the region. Despite limitations, including the lack of clinical trials and references, the study’s basis in anatomical principles and precise, minimal BTX-A dosing highlights its potential as a safe, effective supplement for double chin and facial rejuvenation treatments.
DISCLOSURES
The authors have no financial interest to declare in relation to the content of this article. This study was funded by the Natural Science Foundation of Shaanxi Province grant (NSFSX: 2021JM-239).
PATIENT CONSENT
The patients provided written informed consent for the use of their images.
Footnotes
Published online 3 March 2025.
Disclosure statements are at the end of this article, following the correspondence information.
REFERENCES
- 1.Awaida CJ, Jabbour SF, Rayess YA, et al. Evaluation of the microbotox technique: an algorithmic approach for lower face and neck rejuvenation and a crossover clinical trial. Plast Reconstr Surg. 2018;142:640–649. [DOI] [PubMed] [Google Scholar]
- 2.Yin Y, Li T, Wang C, et al. Treatment of facial flaccidity and sagging after botulinum toxin A injection into the masseter. Plast Reconstr Surg. 2023;151:521–525. [DOI] [PubMed] [Google Scholar]
- 3.Witmanowski H, Błochowiak K. The whole truth about botulinum toxin — a review. Postepy Dermatol Alergol. 2020;37:853–861. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Scarano A, Amore R, Greco Lucchina A, et al. Reduction of double chin without surgery using ascorbic acid and ascorbyl-palmitate solution: a clinical study. Eur Rev Med Pharmacol Sci. 2023;27:109–113. [DOI] [PubMed] [Google Scholar]
- 5.Li H, Zhao H, Chen X, et al. Application of three-dimensional technology in evaluating the lower face lifting by regional platysma injection with botulinum toxin-A. Aesthetic Plast Surg. 2022;46:2480–2487. [DOI] [PubMed] [Google Scholar]
- 6.Yeh YT, Peng JH, Peng HP. Literature review of the adverse events associated with botulinum toxin injection for the masseter muscle hypertrophy. J Cosmet Dermatol. 2018;17:675–687. [DOI] [PubMed] [Google Scholar]
- 7.de Castro CC. The anatomy of the platysma muscle. Plast Reconstr Surg. 1980;66:680–683. [DOI] [PubMed] [Google Scholar]
- 8.Zhou R, Fei Y, Sun L, et al. BTX-A rejuvenation: regional botulinum toxin-A injection of the platysma in patients with facial sagging. Aesthetic Plast Surg. 2019;43:1044–1053. [DOI] [PubMed] [Google Scholar]
- 9.Vistnes LM, Souther SG. The anatomical basis for common cosmetic anterior neck deformities. Ann Plast Surg. 1979;2:381–388. [DOI] [PubMed] [Google Scholar]