There are studies that show that within 48 hours,patients notice an onset, but typically we see maximal onset in 5 to 7 days. Also studies using Dysport, Xeomin, show a very rapid onset, sometimes within 2 to 3 days. How long it lasts depends on the dose. If you go to discount place that waters it down, it might only last 4 to 6 weeks; but, in general, the duration is 3 to 4 months; and you get longer duration after several visits. Patients who have been treated for 8 to 10 years break their habit of wrinkling, so they don’t need to use it again for 6 months or more.