Skin Quality and Safety Following Liquid-Form Polycaprolactone for Facial Rejuvenation: A Prospective Single-Arm Study

Prospective human evidence for liquid-form polycaprolactone (PCL) in facial rejuvenation is limited. We evaluated skin-quality changes and adverse events following treatment. Thirty participants received three monthly superficial subcutaneous (clinically intended subdermal) treatments in an uncontrolled prospective study. Skin mechanical, pigmentary, hydration, and sebum measurements were assessed through 6 months. The registered Antera primary outcomes are not included in this focused report. Instrumental measurements were also collected at 9 and 12 months but were excluded after calibration-related reliability concerns were identified during review of the late dataset; an institutional review board amendment subsequently restricted instrumental reporting to 6 months. Analyses used mixed-effects models; the corrected analysis of the delayed-to-immediate deformation ratio (R6) used restricted maximum likelihood and Bonferroni-adjusted baseline comparisons. All 30 participants completed treatment; attendance was 29 at 1 month and 28 at 3 and 6 months. Maximum skin deformation (R0) decreased from 0.153 ± 0.062 to 0.112 ± 0.105 mm at 6 months. The delayed-to-immediate deformation ratio (R6) decreased from 0.307 ± 0.307 to 0.174 ± 0.277 (adjusted p = 0.038; overall p = 0.001). Hydration decreased. Bruising, swelling, and persistent postprocedural pain were reported; one swelling event was moderate and the remaining events were mild. All resolved without specific treatment. No serious adverse events were reported in the available safety summary. Skin mechanical changes were observed following liquid-form PCL treatment. The uncontrolled design, variability, and retrospective restriction of instrumental reporting limit conclusions about efficacy, mechanism, and long-term durability. Larger controlled studies are needed. Thai Clinical Trials Registry, TCTR20250209003; retrospectively registered on February 9, 2025. This study explored changes in skin measurements after three monthly injections of liquid-form polycaprolactone in 30 adults. There was no untreated comparison group. Some measures of skin deformation changed after treatment, while skin hydration decreased. Bruising, swelling, and pain after treatment were reported; one swelling event was moderate and the other reported events were mild. They resolved without specific treatment. The study registry also included Antera-based wrinkle and texture outcomes, but this article is a focused report of probe-based skin measurements and safety. Instrumental results are reported only through 6 months because calibration-related reliability concerns were identified after the 9- and 12-month measurements had been collected; the subsequent reporting restriction was approved by the institutional review board. The findings cannot prove that the injections caused the changes or determine how the product acted in the skin. Larger controlled studies are needed.