Botulinum toxin type A(HSM)

To analyze treatment patterns, dosing variations, and reapplication rates of botulinum toxin type A (BoNT-A) and hyaluronic acid injections, with a focus on sex- and age-related differences in outcomes.

A prospective analysis was conducted on 164 patients treated with BoNT-A and/or hyaluronic acid injections. Patients were categorized by sex and age (<50 years or ≥50 years). Data on dosage, treatment regions, and reapplications were collected and analyzed for statistical significance.

The study highlighted distinct differences in the application of BoNT-A and hyaluronic acid based on sex and age. For botulinum toxin, the average dose per patient was 55.3 ± 12.7 units. Men received higher doses in the procerus (7.7 ± 2.6 vs.5.7 ± 2.2 units, p = 0.02) and nasal muscles (6.5 ± 2.7 vs.5.3 ± 1.7 units, p = 0.02). Significant age-related differences were observed in the orbicularis oculi (11.0 ± 4.1 vs.14.3 ± 5.4 units, p = 0.02) and corrugator muscles (10.7 ± 3.0 vs.10.5 ± 2.2 units, p = 0.02), with patients ≥50 years requiring higher reapplication doses (p = 0.0001). For hyaluronic acid, men required greater volumes in the mandible (p = 0.0001), reflecting differences in anatomical preferences, whereas women received larger volumes in the lips (p = 0.01), chin (p = 0.02), pre-jowls (p = 0.02), and under-eye regions (p = 0.003), which align with more delicate and aesthetic enhancements.

Significant sex- and age-based differences were observed in the application of BoNT-A and hyaluronic acid. Men required higher doses for structural enhancement, while women showed a preference for treatments in aesthetic regions. Patients ≥50 years required higher doses and reapplications, reflecting age-related anatomical changes. These findings highlight the importance of individualized treatment strategies for optimizing outcomes in aesthetic procedures.

Botulinum toxin type A (BoNT/A) is commonly used for both medical and aesthetic purposes. However, approximately 3% of long-term recipients develop resistance, potentially due to antibody formation. Injection technique may influence immunogenicity, yet comparative data remain limited.

This pilot study evaluated antibody responses following intradermal versus intramuscular injection of six BoNT/A formulations: incobotulinumtoxinA, onabotulinumtoxinA, abobotulinumtoxinA, letibotulinumtoxinA1, letibotulinumtoxinA2, and prabotulinumtoxinA. A total of 120 subjects were divided into intradermal and intramuscular groups, with equal distribution across toxin types. Blood samples were collected and analyzed using ELISA to quantify human IgG (hIgG) targeting whole BoNT/A molecules, functional domains, and complexing proteins.

Intradermal injections consistently induced higher BoNT/A-specific hIgG levels than intramuscular injections, except with letibotulinumtoxinA. Anti-functional domain hIgG levels peaked at day 30 and declined thereafter, aligning with the 90-day retreatment interval commonly recommended. Anti-complexing protein hIgG levels remained relatively stable across time points. Notably, all antibody levels remained below thresholds associated with clinical nonresponse.

Intradermal injection of BoNT/A appears to elicit a stronger immunogenic response than intramuscular administration, although antibody levels did not reach clinically significant thresholds. These findings underscore the importance of injection technique and interval planning to mitigate immunogenicity. Given the widespread use of intradermal techniques in aesthetic practice, this study provides important clinical insight into optimizing BoNT/A administration.

TCTR20211215001.