BoNT-A is a purified protein derived from the Clostridium botulinum bacteria which has a unique effect on the human body. It inhibits the release of acetylcholine at the neuromuscular junction. Acetylcholine depolarizes the motor end plate of the muscle and will cause a muscle contraction. BoNT-A effectively will either reduce the intensity of the contraction of the muscle or will eliminate the contraction altogether, depending on the dosage used and strength of the contraction.
Essentially, BoNT-A neurotoxin interrupts the contraction process of the muscles and causes a temporary muscle paralysis. This can last usually anywhere up to three months as the muscle initiates new acetylcholine receptors and the growth of branches from the neurons to form new synaptic contacts. Gradually the muscle returns to its full function and with no side effects whatsoever.