SAFETY AND EFFICACY OF BOTULINUM TOXIN TYPE A IN FACIAL REJUVENATION: A NARRATIVE REVIEW

Abstract

This narrative review analyzed scientific evidence on the safety and efficacy of botulinum toxin type A for facial rejuvenation. Searches were conducted in August 2026 in PubMed/MEDLINE, Scopus, Web of Science, and Embase, covering 2015 to 2026, and were complemented by a targeted search in PubMed/MEDLINE and Europe PMC. The 635 records retrieved from the four databases were supplemented by texts from the complementary search and from a previously assembled collection, assessed against the same criteria; 30 publications comprised the final corpus, including clinical trials, observational studies, reviews, meta-analyses, and consensus statements. Efficacy was most consistently demonstrated for glabellar lines, with additional support for forehead and lateral canthal lines. Effect duration varied according to formulation, dose, anatomical region, injection technique, and response criterion, preventing equivalence between units of different products. Adverse events were predominantly mild and transient, although ptosis, asymmetry, and functional changes remain clinically relevant. Neutralizing antibody formation was rare under the assessed conditions. Botulinum toxin type A therefore showed efficacy and a generally favorable safety profile for the indications studied, provided that treatment planning considers anatomy, product, dose, volume, injection depth, and injection sites. Methodological heterogeneity limits comparisons among formulations and protocols.