This is a prospective, multicenter, randomized, evaluator-blinded, parallel-controlled, non-inferiority clinical study designed to evaluate the safety and effectiveness of the ULTRAFORMER MPT PLUS, a high-intensity focused ultrasound (HIFU) device, for lifting and tightening lax submental (beneath the chin) and neck tissue in adult subjects.

Approximately 273 subjects will be enrolled at multiple investigational sites across the United States.

Participants will receive either the ULTRAFORMER MPT PLUS treatment or the predicate comparator device, and will be followed for safety and efficacy assessments including clinical photography, investigator evaluation, and patient-reported outcomes.

The study aims to demonstrate that ULTRAFORMER MPT PLUS is non-inferior to the approved reference device in improving skin laxity and wrinkle appearance of the lower face and neck.

This prospective, multicenter, randomized, evaluator-blinded, parallel-controlled, non-inferiority clinical investigation is conducted under an FDA Investigational Device Exemption (IDE #G250041) to evaluate the safety and effectiveness of the ULTRAFORMER MPT PLUS (Class II high-intensity focused ultrasound system) for aesthetic improvement of submental and neck tissue laxity.

A total of approximately 273 subjects aged 30-65 years with mild-to-moderate skin laxity in the submental and neck areas will be enrolled across up to 5 U.S. investigational sites. Subjects will be randomized 1:1 to receive either ULTRAFORMER MPT PLUS or the comparator device (ULTHERA® System, Merz Aesthetics, USA).

Primary endpoints include blinded investigator-assessed improvement using the validated Facial Laxity Grading Scale and safety outcomes based on the incidence and severity of device-related adverse events. Secondary endpoints include participant-reported improvement scores, digital image analysis, and durability of effect at 8-week and 12-week follow-ups.

The study consists of two sequential safety stages (Stage 1A and 1B; 20 subjects total) followed by the pivotal Stage 2 phase (approximately 253 subjects). Data from the safety stages will be reviewed by an independent Data Safety Monitoring Board (DSMB) prior to progression to Stage 2.

All treatments will be performed by trained investigators according to the protocol-defined parameters. Subjects will be evaluated at baseline, post-treatment, and during follow-up visits up to 6 months. The final statistical analysis will assess non-inferiority of ULTRAFORMER MPT PLUS to the predicate device with respect to the primary efficacy endpoint and confirm overall safety.

Inclusion Criteria:

1. Male or female subjects aged 30 to 65 years, inclusive, at the time of informed consent.
2. Subjects presenting with mild to moderate submental and/or neck skin laxity, as determined by the investigator.
3. Subjects in good general health with stable body weight (±5%) for at least 6 months prior to screening.
4. Subjects willing to avoid other aesthetic or dermatologic procedures (surgical or non-surgical) to the treatment area during the study period.
5. Subjects able to understand and sign informed consent and comply with all study visits and procedures.
6. Female subjects of child-bearing potential who agree to use reliable contraception throughout study participation.

Exclusion Criteria:

1. Prior facelift, neck lift, liposuction, or contouring surgery involving the lower face, submental, or neck areas.
2. Receipt of any energy-based aesthetic treatment (e.g., HIFU, radiofrequency, laser) or injectable aesthetic treatment (e.g., botulinum toxin, dermal filler, collagen stimulator) to the treatment area within 6 months prior to baseline.
3. Presence of any implanted electronic medical device, such as a pacemaker, defibrillator, or neurostimulator.
4. Active skin infection, wound, cystic acne, inflammation, or severe scarring within or near the treatment area.
5. History of keloid formation or abnormal wound healing.
6. Known bleeding disorder, or use of anticoagulant or antiplatelet medications that cannot be safely discontinued for the procedure.
7. Pregnant or breastfeeding women.
8. Subjects with a known sensitivity or contraindication to ultrasound-based procedures.
9. Any medical or psychiatric condition that, in the investigator's judgment, could interfere with study participation, safety, or data integrity.
10. Participation in another investigational study within 30 days prior to screening.

This study is evaluator-blinded. Participants and outcomes assessors will remain blinded to treatment allocation, while treatment providers will be unblinded to operate the assigned device.