Thanks for your inquiry. Most people will see an effect within 3-7 days; if after several weeks there is no apparent difference I'd recommend contacting your injector because you may simply need a higher dose.
Botox is a safe and reliable neuromodulator that is FDA approved for the vertical glabellar creases or "frown" lines. Approximately 15 to 20 units of Botox injected directly in the Corrugator muscles will soften and smooth the central brow area and diminish vertical lines in this area. This is an in-office procedure which takes about 15 minutes. It does take about 2 to 5 days to see the onset of action and about two weeks for the final result. Botox will last about 3 months in this area if injected in an appropriate amount and in the right areas.