An investigation published Online First by the Archives of Facial Plastic Surgery reveals that the onset action of two botulinum neuromodulators both improved the appearance of crow’s feet (lateral orbital rhytids), even though one appeared to produce greater improvement than the other.

The authors said:

“Botulinum toxin is a potent neuromodulator produced by the bacterium Clostridium botulinum. Botulinum toxin exerts its effect by blocking the action of acetylcholine (a neurotransmitter), thus producing a state of functional denervation.”

77 women and 13 men with moderate-to-severe lateral orbital rhytids were enrolled to participate in the study by Kenneth C.Y. Yu, M.D., from The Maas Clinic, San Francisco, and the University of California San Francisco and colleagues. Participants received an injection of onabotulinumtoxinA, 10 U, on one side of their face and abobotulinumtoxinA, 30 U, on the other side of their face. The team based dose ratio of the products on clinical evidence.

The researchers explain:

“Treatment sides of the face were randomized with a computer-aided software. Preparation of the product was performed by a unblinded registered nurse, who was responsible for maintaining the investigator and participant blinding.”

The team took photos of participants prior to treatment and on days 2, 4, and 6 after the injections.

The team report:

“AbobotulinumtoxinA and onabotulinumtoxinA demonstrated statistically significant change from baseline at day two in the treatment of lateral orbital rhytids at maximal contraction and rest when evaluated independently by investigator and participant. By day four, the greater improvement achieved with abobotulinumtoxinA reached statistical significance and remained superior at day six.

It is unclear whether our observations will translate to other sites, such as the glabella [space between the eyebrows] and forehead.”

During the investigation, the researchers observed no side effects or complications with either product.

Written by Grace Rattue