A lot of patients who have not experienced acupuncture before are often nervous about the level of pain they will experience. The needles used are about the thickness of a human hair. Some needles may not be felt at all during insertion. During manipulation of the needles patients will often experience, a warm sensation, tingling, or in some cases a dull ache, practitioners call this Deqi. This is a good indication that the treatment will be effective. The needles are left for 20 to 30 minutes, and a feeling of deep relaxation will occur, in some cases patient’s drop off to sleep during this time.