Facial rejuvenation after intradermal botulinum toxin: is it really the botulinum toxin or is it the pricks?

BACKGROUND The use of intradermal botulinum toxin A (onabotulinumtoxinA) remains a relatively new technique and is an off-label cosmetic application for facial skin rejuvenation. There is little documented clinical evidence of the objective benefits of this therapy. PURPOSE To determine whether intradermal facial onabotulinumtoxinA injection has any benefits. STUDY DESIGN Interventional, comparative, split face clinical trial. METHODS Informed consent was obtained from 10 physicians. One half of the physician's faces were randomly injected with onabotulinumtoxinA (2 U/0.1 mL; 30 facial injections on half of the face, each 0.1 mL) intradermally and the other half of the face with normal saline (30 facial injections on half of the face, each 0.1 mL). The injecting clinician and the subjects were blinded to the contents of the syringes. One and 4 weeks later, two neutral, blinded observers assessed the subjects in person. The patients were also photographed in ambient light surroundings and the same observers compared the halves of their faces in photographs and rated them on a scale of -4 to +4. RESULTS Global improvement in skin texture and tightness was noted in the post-treatment photographs (the skin appeared to be tenser and smoother), although there was no difference between the two groups and, hence, the changes could not be clinically ascribed to the intradermal botulinum toxin injections. No other meaningful clinical difference could be demonstrated between the two sides of the face, in any of the 10 subjects, in person or in photographs. The small study sample precluded formal statistical analysis. CONCLUSION Intradermal botulinum toxin A injection does not appear to have any benefit in facial rejuvenation. The authors have indicated no significant interest with commercial supporters.