I just could do without it! It's an incredible feeling every time the evening in bed when I put it, I ask myself every time how I do the day without! I recently used to play tennis, it helps to really breathing in the effort as well. So yes it's true the day after the first use I had painful irritation in the nose, ca lasted three days and I have not been able to use. The fourth day I had a little trouble falling asleep but from the 5d I have not felt anything and I have now no problem or discomfort.