Dr. Theo Kousouli, a chiropractor, hypnotherapist - holistic healer and author, describes the sound the adjustment makes is harmless and just gases, O, CO2, N, escaping the capsules and going back into the bloodstream. Only a qualified chiropractor should move bones as they are trained to do it without pain and maximal benefit to the patient. Dr. Kousouli specializes in personal growth and empowering therapies to better oneself. www.drkousouli.com and kousoulimethod.com for more info.