10mg is enough if you don't have experience with that drug. 20mg or more would knock you out for sure. I used Zolpidem for the last 1.5 years to fall asleep and it helped me a lot, I usually take 5mg, which is enough to put me to sleep. 10mg gives me a cozy, warm feeling. I did more than 10mg a night in the past and it literally make me black out while watching TV or stuff like that.