 Both "in vitro" (outside a living organism) and "in vivo" (using a living organism) tests have been carried out, but no double-blind anti-wrinkle studies are available.In a 2012 double-blind, placebo-controlled trial investigating treatment of blepharospasm (abnormal contraction or twitch of the eyelid), botulinum toxin injections with subsequent acetyl hexapeptide-3 treatment were compared to botulinum toxin injections with placebo cream treatment.Of the 12 patients in the acetyl hexapeptide-3 group, four experienced an extension of symptom control by 3.3 to 7.1 months.