Hyperhidrosis is an excessive sweating condition that exceeds the amount necessary for normal thermoregulation. In patients with hyperhidrosis, the issue arises when sweating becomes excessive and not aligned with the ambient temperature.

Although the exact cause of hyperhidrosis is unknown, it involves an overactivity (dysregulation) of the sympathetic component of our autonomic nervous system, which sends unnecessary signals to the sweat glands to increase their production. Therefore, the fundamental cause appears to be neurological rather than cutaneous.

Sweat glands are innervated by the sympathetic nervous system, with acetylcholine being the primary neurotransmitter. Botulinum toxin (Botox) temporarily inhibits the effect of acetylcholine, thereby interrupting the overactivity of the sweat glands. Botox blocks the messages from the nerves instructing the sweat glands to produce sweat, effectively reducing sweating.
The decrease in sweat production starts to become noticeable after 3-4 days, with the maximum effect typically occurring around 2-4 weeks post-treatment.