WEDNESDAY, May 28, 2025 (HealthDay News) -- Specific quantitative differences exist between four botulinum toxin A formulations used in the treatment of glabellar strain, according to a study published online May 28 in JAMA Dermatology.

Mehdi S. Lemdani, from the University of Pennsylvania in Philadelphia, and colleagues provide an objective quantitative assessment of the effect of four botulinum toxin A formulations on glabellar strain in a single-center, double-blind clinical trial. Participants were randomly assigned into four treatment arms receiving one dose into the glabellar region (GR) of 20 units of onabotulinum toxin A (OBoNT/A); 60 units of abobotulinum toxin A (ABoNT/A); 20 units of prabotulinum toxin A (PBoNT/A); or 20 units of incobotulinum toxin A (IBoNT/A). The change in GR dynamic strain after injection over time was measured as the primary outcome.

The study recruited 143 women (mean age, 43.5 years). The researchers found that at day 3, ABoNT/A and PBoNT/A had the fastest onset. Compared with their baseline, PBoNT/A and IBoNT/A retained efficacy at day 180. Increased improvement with treatment was seen as a result of increasing baseline glabellar strain severity. With decreasing GR strain, lateral canthal region strain increased. Compared with OBoNT/A, PBoNT/A was significantly more effective at day 180. Improvement in related FACE-Q module scores was seen in all arms up to 90 days.

"This randomized clinical trial demonstrated precise quantitative differences between four BoNT/A formulations in treating glabellar strain with significant clinical implications," the authors write. "ABoNT/A and PBoNT/A demonstrated significantly faster onset than OBoNT/A or IBoNT/A."

Several authors disclosed ties to biopharmaceutical companies, including Evolus, which manufactures Jeuveau (prabotulinum toxin A) and funded the study.

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