How does the mechanism by which Botulinum Toxin (Botox) application reduces wrinkles work biologically?

Botulinum toxin temporarily blocks the release of a neurotransmitter called “acetylcholine” at the motor nerve endings in the injected area. When acetylcholine cannot be released, the “contract” command from the nerve to the muscle cell cannot be transmitted, and a temporary relaxation (paralysis) occurs in the affected facial muscle. Because the muscle cannot contract, the skin layer covering it also cannot fold, and over time, deepening facial lines (forehead, crow’s feet, between the eyebrows) relax and become smoother. This process is not permanent; the body restarts muscle activity by creating new nerve sprouts (axonal sprouting) within an average of 4-6 months.