The purpose of this study is to assess the effectiveness and safety of Gana X, a Poly L-lactic acid filler for the aesthetic treatment of buttocks.

A screening visit will allow to inform and preselect the participants.

On D0, baseline scoring, fringe projection acquisitions and photographs will be done before injection. Eligible participants will receive a first injection of the product. Immediately after injection, injector's treatment satisfaction will be collected. Investigator evaluator will collect Adverse Events (AEs) and Injection Site Reactions (ISRs) immediately after injection.

A month and a half after initial injection (M1 and a half), clinical scoring, fringe projection acquisitions and photographs will be done before touch-up (if applicable). Participant's treatment satisfaction and injector's treatment satisfaction (if applicable) will be collected. A touch-up injection will be made if necessary, according to injector and participant opinion. Investigator evaluator will collect AEs and ISRs before and after touch-up if applicable.

Six (M6), nine (M9), twelve (M12), eighteen (M18) and twenty-four (M24) months after initial injection, clinical scoring, fringe projection acquisitions and photographs will be done. Participant's treatment satisfaction will be collected. Investigator evaluator will collect AEs and ISRs.

Inclusion Criteria:

• Subject with mild to moderate buttock volume depression and/or seeking buttocks volume augmentation based on investigator evaluation.
• Subject wiling to abstain from other body contouring procedures during the whole study period.
• Subject psychologically able to understand the study related information and to give a written informed consent.
• Subject having given freely and expressly his/her informed consent.
• Subject willing to have photographs taken.
• Subject affiliated to a health social security system.
• Female of childbearing potential should use a contraceptive regimen recognized as effective since at least 12 weeks before screening visit and during the whole study period.

Exclusion Criteria:

• Pregnant or nursing woman or having given birth within the last year or planning a pregnancy during the study.

• Excessive subcutaneous fat in the area to be treated.

• Excessive skin laxity on the area to be treated.

• Severe buttocks ptosis.

• Subject who had been deprived of their freedom by administrative or legal decision or who is under guardianship.

• Subject in a social or sanitary establishment

• Subject participation to another research on human beings or who is in an exclusion period of one.

• Subject having already received 4500 euros indemnities for participation in research involving human beings in the 12 previous months or exceeding these 4500 euros with his participation in the present study.

• Subject suspected to be non-compliant according to the investigator's judgment.

• Subject suffering from a severe or progressive disease or any other pathology that may interfere with the evaluation of the study results.

• Subject with known history of or suffering from autoimmune disease and/or immune deficiency.

• Subject with a history of cellulitis, streptococcal disease, such as acute rheumatic fever or recurrent sore throats and in case of acute rheumatic fever with heart complications.

• Subject suffering from inflammatory and/or infectious cutaneous disorders in or near the studied zones (e.g. acne, chronic eczema, atopic dermatitis…).

• Subject with an abscess, unhealed wound, or a cancerous or precancerous lesion on the studied zone.

• Subject prone to develop inflammatory skin conditions or having tendency to bleeding disorders.

• Subject with a tendency to develop keloids or hypertrophic scarring.

• Subject with significant scarring, open wounds, lesions or tattoos in or near the area to be treated.

• Subject having history of allergy or anaphylactic shock including hypersensitivity to Poly-l-lactic acid, to lidocaine or to one of the components of the tested devices or antiseptic solution.

• Subject having received a dose of COVID-19 vaccine within the 14 days prior to injection visits or planning to receive a dose in the 14 days following injections.

• Subject having received treatment on or near the buttocks (laser, dermabrasion, surgery, radiofrequency, cryolipolysis, buttocks electrostimulation, endermologie, liposuction, other energy-based treatment, surgery…) within the 12 months prior to screening visit.

• Subject having received injection with a resorbable filling product in or near the buttocks within the 12 months prior to screening visit.

• Subject having received at any time the following treatments in the area to be treated:

  • Buttocks implants;
  • Buttocks fillers (e.g., silicone, semi-permanent or permanent fillers or autologous fat injections);
  • Injections for the treatment of cellulitis.

• Subject having started or changed her oral contraceptive or any other hormonal treatment during 12 weeks prior to screening visit.

• Subject using medication such as aspirin, nonsteroidal anti-inflammatory drugs (NSAID) (ibuprofen, naproxen, …), antiplatelet agents, anticoagulants or other substances known to prolong bleeding time within 1 week prior to injection visits.

• Subject undergoing a topical treatment on the test area or a systemic treatment:

  • Antihistamines during the 2 weeks prior to injections visits (D0 and touch-up visit).
  • Immunosuppressors and/or corticoids during the 4 weeks prior to injections visits (D0 and touch-up visit).
  • Retinoids during the 6 months prior to injections visits (D0 and touch-up visit).

• Intensive exposure to sunlight or UV-rays within the month before injection visits and one month after.

• Subject planning to loss or gain weight for the duration of the study.

• Subject planning to change her/his life habits during the study

Participants and investigators assessors will know which filler was used.