Is it four weeks? Six weeks? More perhaps? Well, first, you need to understand that the process of permanent hair removal is gradual and has multiple phases. After 4-6 weeks of use, you will notice a decrease in hair regrowth.
Semi-permanent results will start showing after ten treatments (10 weeks) and hair regrowth will be inhibited as long as you keep using the device during the maintenance phase. After this initial phase, you should decrease the frequency of treatments in half and use it for ten more treatments to see permanent results.