Botox®, Dysport®, and Xeomin® are naturally occurring toxins (Clostridium Botulinum Toxin type A) created by the bacteria Clostridium botulinum. Yes, it is the bacteria that causes botulism; however, since only the toxin is being injected you cannot get the disease from Botox®, Dysport® or Xeomin®, injections. Because these toxins specifically affect nerve endings, they are called neurotoxins. The toxin is grown in a lab, sterilized and purified before being bottled, packaged and frozen. Prior to injection, the product is reconstituted with sterile saline solution by the treating physician.
Nerves communicate with muscles using molecules called neurotransmitters which are stored in tiny amounts inside of small pockets located at the end of the nerves. When you want a muscle to move, an electrical impulse starts in your brain and travels down a series of nerves, eventually reaching to the end of the nerve going to the specific muscle you want to move. The electrical impulse causes the neurotransmitters to be released by the nerve endings, which are then taken up by the muscle end plates, stimulating contraction of the muscle.
When Botox®, Dysport®, and Xeomin® are injected into the muscle to be affected, the toxin is absorbed by the nerve endings and it inhibits the release of the neurotransmitters. As a result, an electrical impulse passing down the nerve no longer results in contraction of the muscle because the communication mechanism has been disabled. So, when they are injected into the muscles of the brow, an attempt to frown is unsuccessful because the brow muscles can no longer communicate with their nerves. Consequently, brow furrows are not able to form and the area looks smoother and more relaxed. Depending on the size of the muscle and how much toxin is injected, some of the nerve endings may not be completely disabled. As a result, the muscle may not be completely relaxed and some motion may remain. Some patients prefer to keep some muscle motion as a more natural look and to allow some facial expression in that area.
Nerves also communicate with sweat glands in the same way that they communicate with muscles. This is why Botox®, Dysport® and Xeomin® can also be used to treat excessive sweating (hyperhydrosis) in the underarms, hands and feet. To accomplish this, numerous small injections are performed about one half of an inch apart in the areas to be affected. After several days, the sweat glands are no longer able to be stimulated by nerve impulses and sweating is dramatically reduced. While Botox®, Dysport® and Xeomin® last about three and one half months in inhibiting muscle contractions, most patients treated for excessive sweating find that the effect lasts six months or longer.
The masseter muscles are the strongest jaw muscles and are located on the sides of the mandible (jaw bone). Excessive use of these muscles can cause them to grow disproportionately (hypertrophy) with respect to the rest of the face. Botox®, Dysport® and Xeomin® can be used to weaken and shrink these muscles to reduce jaw pain, improve facial proportions and lessen grinding of the teeth at night (bruxism).