Injection of botulinum toxin is the most common cosmetic procedure performed in the world today. There are several formulations available for patients to choose from including BOTOX® Cosmetic, Dysport®, Xeomin® and Myobloc®. The most popular formulation continues to be BOTOX® Cosmetic, but in the last few years it appears more physicians and patients are discovering the benefits of Dysport®. Xeomin® is also another very useful formulation of botulinum while Myobloc® mainly has other applications not related to the treatment of wrinkles or the aging face.
The process by which these medications assert their effect begins with uptake of the botulinum, which is a complex protein, into the nerve ending. A specialized portion of the protein interacts with a synaptic vesicle receptor complex that likes to bind glycoproteins. Once inside the nerve cell, the specialized part of the botulinum protein dissociates and the working part of the toxin blocks the transport of acetylcholine out of the nerve. Acetylcholine is an important neurotransmitter used in humans and when blocked, the muscles of expression cannot move. Acetylcholine blockade also prevents sweating in the area where injected. The effect of BOTOX® Cosmetic, Dysport®, and other neuromodulators are nonpermanent.
The onset of effect after the injection has been studied well. BOTOX® Cosmetic and Dysport® have similar onset with a mean time to see effects around 2 to 3 days after the injection. Importantly, it takes about two weeks to see the maximal effect and it is normal to have some movement in the injected areas up to that point. We recommend to all patients to have a follow up visit two weeks after the injection to assess whether more injectable is needed. Xeomin® effects seems to occur a little faster when compared to Dysport® and BOTOX® Cosmetic.
The duration of the effect has also been studied very well. In the frown area, investigators noted the effect lasted 3 months in 75% of patients, while 25% of patients experienced relaxation of the muscles up to 4 months with BOTOX® Cosmetic. In other words, with BOTOX® Cosmetic, most patients will need to be re-dosed at 3 to 4 months. In a Dysport® study involving 700 patients, the median duration of effect was also 3 to 4 months. This means the average Dysport® patient will likely require re-dose at 3 to 4 months. Some patients in our practice, have reported Dysport® lasting longer than 4 months. Xeomin® is a bit different and most investigators believe the re-dose for Xeomin® may have to occur at 2 to 3 months.
Neuromodulators can be injected into many parts of the human face and neck. These can be injected where relaxation of the underlying muscles can cause a positive effect for the patient. The only FDA-approved area for wrinkles is the frown area. However, physicians have a broad experience using these medications off-label in other parts of the face. This includes relaxation of the wrinkles in the Crow’s feet area, the forehead, the chin, neck, and nose. All these areas require different doses which an experienced injector can suggest to you.
In addition, relaxation of certain muscles can also elevate sagging parts of the face in an effective, but more natural manner. This includes the “chemical” brow lift, the peak of the brow, and the corners of the mouth. Facial reshaping can also be performed and is one of my favorite procedures to perform to create a subtle beautification of the human face. This seems to be particularly rewarding when aging leads to a rounded face appearance while the neuromodulator injection creates a more ideal facial ogive.
Different people need different doses. Treatment for all these medications must be individualized to get the best outcome and minimize the side effects and have lower risks. Generally speaking, most men need higher doses when compared to women. However, being a woman does not mean you should always get less. Instead, the results of the injections should be guided by the desired outcome. Looking natural and having a small amount of movement seems to be the preferred approach when compared to those who want the “frozen” look. We always recommend starting with the lowest effective dose and working your way up in order to have the best results.