Botox, Dysport, and Xeomin are supposed to interfere with facial muscle activity. All work by inhibiting the release of the neurotransmitter, acetylcholine, across the neuromuscular junction. In other words, they prevent the release of the chemical signal from the nerve ending that stimulates the muscle to contract. When that chemical (acetylcholine) is reduced, or blocked completely, the muscle relaxes. The result is weakness or paralysis of the muscle, depending upon the amount of botulinum toxin present.
Botox, Dysport, and Xeomin are all serotype A botulinum neurotoxins (BoNT-A). As a result they have very similar activity and characteristics, and are more similar than they are different; the actual “toxin” molecule in each is essentially identical.
If these products are administered in larger doses, or placement of the product is incorrect, weakness or paralysis may occur in nearby muscles which were not intended to be treated. For this reason it is important that you seek and experienced injector.
Treatment for lines of the forehead and the corners of the mouth are considered “off -label”, since these products are FDA approved for treatment of moderate to severe frown lines of the glabella. Transverse forehead lines are treated by injecting the frontalis muscles within the forehead. Down-turned (lines) corners of the mouth can be improved by injecting the depressor anguli oris (DAO) muscles; this muscle is treated at some distance from the corner of the mouth.
Unsatisfactory results can occur following treatment of either forehead lines or down-turned corners of the mouth. The most common complication following treatment of forehead lines is brow ptosis; the eyebrows droop and patients often feel a heavy brow or heaviness in their upper eyelids. The most common complication following treatment of the DAO is weakness of adjacent muscles or some asymmetry in movement of the mouth. An experienced BoNT-A injector will know the pertinent facial anatomy of these areas, as well as the proper dosing range, both of which are important in avoiding unexpected outcomes.
Drooping corners of the mouth can also be improved by using a soft tissue filler. The best elevation of the corners of the mouth may result from combination therapy utilizing a filler and BoNT-A.
Best wishes, Ken Dembny