Use of Micro Botulinum Toxin for a Face-lifting Effect: A Systematic Review

BACKGROUND Micro-Botox (Micro-btx) was described in 2000 for the paralysis of superficial muscle fibers to address facial rhytides. Increasingly, there are reports of its off-label use for a face-lifting effect. OBJECTIVE To evaluate the literature for such results. METHODS AND METHODS A systematic review was performed according to PRISMA; only Level >= III evidence from 2000 to 2020 were included. Data extracted include patient demographics, type of botulinum toxin, dilution, dosage, injection sites and spacing, needle size and syringe, follow-up, patient and physician assessment, and complications. RESULTS Three hundred seventy-two patients (average 35.2 years) underwent different botulinum toxin injections (average 39 units/hemiface) of varying dilutions with 30- to 32-G needles, typically with 1-mL syringes, by forming 0.2- to 0.5-cm wheals 1 cm apart. Follow-up averaged 10.5 weeks with both subjective and objective assessments. Facial asymmetry and minor bruising were common. Subjective assessment of face-lifting effects between patients and physicians was highly discordant and injection sites reported were highly variable. CONCLUSION Much heterogeneity in dosage, injection sites, definition of "face-lifting," and assessment methods remain, all of which preclude accurate and objective evaluation of the current evidence for micro-btx. Future studies should address these variables, given the growing interest in such nonsurgical options for a face-lifting effect.