Exploring the Safety and Satisfaction of Patients Injected With Collagen Biostimulators-A Prospective Investigation Into Injectable Poly-l-Lactic Acid (PLLA)

Background: Esthetic medicine has shifted significantly toward non-surgical procedures, with the collagen biostimulator poly-l-lactic acid (PLLA) becoming increasingly popular for facial rejuvenation. However, the safety and patient satisfaction associated with PLLA facial treatments remain largely unexplored.

Objective: This study aimed to evaluate the safety profile of PLLA treatment and assess patient mid- and long-term satisfaction with the outcome.

Methods: This prospective single-center study was conducted at Bravo Clinic in Rio de Janeiro from August 2023 to August 2024. The patients' mid and lower face was treated by injecting Rennova Elleva (a collagen biostimulator containing 210 mg of PLLA) into the zygomatic and pre-masseteric regions. All patients underwent monthly clinical evaluations for the first 150 days and kept diaries to self-record any adverse effects during the first 30 days. Patient satisfaction was measured using the Global Aesthetic Improvement Scale (GAIS) on days 90 and 150 post-injection.

Results: The study included 52 female patients [mean age: 49.87 ± 10.7 years; mean body mass index (BMI): 23.99 ± 3.5 kg/m²]. Patients reported mild to moderate injection site reactions, including redness, pain, hardening, swelling, lumps, bruises, and skin discoloration, with most symptoms resolving within a few days. Clinically, no major adverse events were noted, except for one small, painless nodulation that resolved without intervention. On post-injection Day 90, the average GAIS was rated at 2.32 ± 1.0. This rating remained stable at Day 150, with an average GAIS of 2.32 ± 0.8 (p = 0.862). Inverse correlations were identified between the duration of mild pain and GAIS (r_s = -0.546, p = 0.035), as well as between the duration of mild bruises and GAIS (r_s = -0.598, p = 0.019). The duration of moderate pain was significantly associated with age (r_s = -0.894, p = 0.041).

Conclusion: Rennova Elleva, a PLLA-based collagen biostimulator, is safe and well-tolerated with a low incidence of adverse effects. It provides long-lasting, satisfactory results for patients with mild to moderate facial sagging, rendering it an effective non-surgical option for enhancing facial esthetics.