For the underarms the median is about six months, longer than other areas. It does not remove the sweat glands themselves — it only cuts the nerve signal that triggers them, so sweating returns as the nerve recovers. That is why it is repeated, often timed to arrive before the sweatiest season.

As sweating drops in the treated area you may feel it has increased elsewhere. Rather than the total shifting, what usually happens is that underarm sweat disappears and the rest stands out by comparison. For most people it is not disruptive, but if it bothers you the consultation can plan the areas in stages.

Sweating begins to drop within three to seven days. Blocking the nerve signal takes very little time, which makes this the fastest-acting of the botulinum treatments. It becomes clearer over the first two or three weeks, and for the underarms people usually notice the change as a visible drop in marks on clothing.