What is the primary function of OnabotulinumtoxinA (Botox)?

OnabotulinumtoxinA, widely known as Botox, primarily functions by blocking signals from the nerves to the muscles. When injected, it prevents the release of the neurotransmitter acetylcholine at the neuromuscular junction, which is crucial for muscle contraction. As a result, the targeted muscles become temporarily paralyzed or weakened, reducing their ability to contract. This mechanism is the basis for Botox's use in various medical conditions, including muscle spasms and certain types of chronic pain, as well as its well-known cosmetic applications for reducing wrinkles.

Understanding this action is critical because it distinguishes Botox from other treatments that may aim to enhance muscle function or stimulate nerves. Thus, its primary function is about inhibiting nerve signals to cause a decrease in muscle activity.