Prospective Clinical Investigation to Evaluate the Safety and Effectiveness of Juläine™ in Improving Gluteal Skin Laxity in Adults.

Inclusion Criteria: * Adults aged 18 to 55 years; * Body Mass Index (BMI) between 18.5 and 24.95 kg/m². * Skin laxity of the gluteal region defined as sagging and reduced tightness of the skin. * Women of childbearing potential must be willing to abide by the contraceptive requirements * Ability to understand the study and provide informed consent, attend follow-up visits, and follow post-injection instructions. Exclusion Criteria: * Pregnancy or breastfeeding, or planned pregnancy/lack of adequate contraception (through 8 weeks post-study); * Is planning to donate/bank or retrieve eggs (ova, oocytes) or donate sperm during the study or within 8-weeks of the end of participation of the clinical investigation. * Active infection, inflammation or lesions at or near the treatment site. * Acute infection at screening; * History of autoimmune disease; * Immune deficiencies; * History of hypertrophic scarring or keloid formation; * Previous surgical procedures involving the buttocks * Aesthetic procedure on the buttocks (including fillers, elevation wires, radiofrequency, ultrasound, cryotherapy, fat injection, neurotoxin, laser or light treatment, or chemical peel) within 6 months prior to randomization. * Hemorrhagic disease or ongoing use of antiplatelets/anticoagulant therapy. * Treatment with chemotherapy, immunosuppressive agents, systemic corticosteroids within 3 months before treatment (inhaled or ophthalmic corticosteroids are allowed). * Use of hormonal replacement therapy (HRT) unless the participant has been on a stable dose for at least 3 months prior to screening and does not plan to make any changes to the HRT regimen during the study period. * Use of topical corticosteroids, topical prescription retinoids in the treatment area within 1 month of the Baseline visit or systemic retinoid treatment within 6 months of the baseline visit, or plan to receive such treatment. * Use of other agents that inhibit collagen production. * Known allergy or hypersensitivity to any component of the investigational product. * History of herpes simplex rashes, malignant skin diseases, or any other serious dermatologic or systemic disease. * Presence of any condition that may impair wound healing (e.g., connective tissue disorders, severe malnutrition). * Planned or ongoing cosmetic procedures involving the buttocks or surrounding area during the period of clinical investigation. * Extensive tattoos covering \>50% of the total gluteal area. * Participants actively taking GLP-1 medications with the intention of achieving additional weight loss (expected \>10% during study) will be excluded. Participants on a stable GLP-1 regimen (≥3 months) for diabetes management or weight maintenance, with documented weight stability (±10% in past 6 months) and no planned or expected weight change \>10%, may be included. * Any other medical or psychological condition that, in the opinion of the investigator, may interfere with participation in clinical research or evaluation of results.