Botulotoxine causes interruption of nerve connection by means of blocking receptors on the level of neuromuscular plate It prevents the nerve to instruct the muscle to shrink and the wrinkle does not appear any more. Botulotoxine is effective until the neuromuscular connection recovers, which takes 3 to 4 months (according to literature). The function of the muscle recovers not earlier than after 3 months. The effect is even longer after subsequent application of Botulotoxine.
Afterwards, the muscle gets back to its function and starts to contract again, but usually not with its original strength, as the patient often gets rid of the habit of spontaneous frowning.