Clostridium botulinum is a bacterium that produces the botulinum toxin. When locally applied, to parts of the face for example, neuromuscular transmission is blocked, and muscles that cause wrinkles cannot contract (no more wrinkles). How exactly does the toxin block nueromuscular transmissions?

Botulinum is a toxin that can be used to cure wrinkles in human beings by injecting it in very small concentrations and it works in preventing the signals from the nerve cells to muscles and thus paralyzing them by stopping wrinkle formation.

Wrinkles are caused by the contraction of muscles and this neurotransmitter does not allows the muscles to contract. In order to contract nerves release a chemical messenger called as acetycholine. This neurotransmitter is found at the junction where the nerve cell reaches the muscle cell. This causes contraction of muscles.

Injecting botulinum prevents the release of acetylcholine which prevents the contraction of muscle, causing reduction in wrinkles and muscles become stiff.