Sebum production after botulinum toxin A (Botox, Allergan) treatment for forehead rhytids positively correlates with the distance away from the injection point, according to a new study. Intramuscular botulinum type A injections notably reduce sebum production at injection sites, while increasing sebum production of the surrounding skin, according to the study published May in the Aesthetic Surgery Journal.
Chinese and Italian researchers studied 42 females receiving intramuscular botulinum toxin A injections for forehead rhytides, looking for sebum regulation and gradient surrounding injection sites. They compared two injection doses — two and four units — administered in five standard injection sites, and measured sebum production at baseline and post-treatment.
Researchers found botulinum toxin A treatment resulted in significant change to the sebum at the injection site of both groups, with a sebum gradient surrounding the injection point.
“The efficacy did not improve at higher injection doses, with the four-unit regimen generally not being more potent than the two-unit regimen,” they write.
Sebum production, however, went back to normal levels at the 16-week follow-up for both treatment groups. This suggests the higher four-unit dosage did not result in a longer duration until relapse than the two-unit dose. While sebum production was lower at the injection sites, it increased at a radius of 2.5 cm at the 2-, 4- and 8-week follow-ups, the researchers write.