Hybrid Calcium Hydroxylapatite–Polynucleotide Skin Booster A Retrospective Cohort Study

Background Skin quality is increasingly recognized as a multidimensional construct that includes tone evenness, surface evenness, firmness, and radiance. Injectable ‘skin boosters’ have expanded treatment options for diffuse skin‐quality concerns, and combinations of biostimulatory and regenerative agents are increasingly used in practice. Objective To evaluate the 6‐month effectiveness and safety of a single‐session hybrid calcium hydroxylapatite–polynucleotide (CaHA–PN) skin booster protocol using diluted CaHA and PN in a consecutive real‐world cohort. Methods A single‐center, retrospective observational cohort analysis included 36 consecutive patients treated with a fixed‐dose hybrid protocol. Diluted calcium hydroxylapatite (1.5 mL CaHA (FACETEM, CGBio Inc., Korea), diluted 1:2 with preservative‐free normal saline) was injected in the subdermal plane with a 25‐gauge blunt cannula, followed by intradermal polynucleotide (DOT‐PN, Rejuran, Pharmaresearch; 4.0 mL) administered via micro‐aliquots using a 32‐gauge needle. Standardized photographs were obtained at baseline and 6 months. Two blinded dermatologists graded facial skin quality using a validated 5‐point photonumeric scale (0–4). Secondary outcomes included cheek wrinkle severity (Modified Fitzpatrick Wrinkle Scale framework), clinician‐ and patient‐rated Global Aesthetic Improvement Scale (GAIS), patient‐reported radiance (Likert 1–5), satisfaction, and adverse events. Results The mean age was 45.8 ± 12.3 years (range 17–68) and 32/36 (88.9%) were female. At 6 months, the mean skin quality score improved from 2.7 ± 0.8 to 1.5 ± 0.6 (44.4% improvement; p < 0.001), and mean cheek wrinkle severity improved from 2.4 ± 0.9 to 1.4 ± 0.5 (41.7% improvement; p < 0.001). GAIS indicated improvement (scores 1–3) in 83.3% and 80.6% of clinician assessments and in 91.7% of patient self‐assessments (all p < 0.001). High radiance (Likert ≥ 4) was reported by 86.1% of patients, and 77.8% reported being satisfied or very satisfied at 6 months; 94.4% would recommend the treatment. Transient injection‐site erythema (83.3%), edema (77.8%), and ecchymosis (41.7%) were the most frequent adverse events. Two patients (5.6%) developed delayed nodules that resolved with massage by 8 weeks. No infections, vascular compromise, or serious adverse events were observed. Conclusion In this 36‐patient cohort, a single‐session hybrid CaHA–PN skin booster protocol was associated with significant improvements in facial skin quality and cheek wrinkle severity at 6 months, with high patient‐reported improvement and a favorable safety profile. Prospective controlled studies are needed to define comparative efficacy and to optimize dosing schedules.