I am a non-smoker because of hypnotherapy I undertook in 1994. I had smoked 1.5 packs a day, started smoking 17 years before that. Have never had a single puff since. It cost $40, took place in a hotel ballroom with 150 people at the same time. The program was two hours long. Can't recommend it highly enough--at least for smoking cessation. I am sure it saved my life. I was 37 years old.
I have also been hypnotized three times for weight loss, and none of them "took." Maybe because you still do have to eat? Whereas, the smoking cessation was cold turkey. No patch, no gum, no drugs, no cutting down first--just done. The post hypnotic suggestion was that as soon as the thought of wanting a cigarette entered your mind, a completely different thought would jump in and occupy you. This happened over and over for me. "Oh, I want to smoke a cig---gee, I better get to my laundry or I will have no clean clothes left." And I would go start sorting my laundry. The thought of smoking would enter my mind again 5 minutes later (in those first couple of days, it was that frequent) and suddenly I would remember that I never called so-and-so back. So I would stop working on the laundry, make that quick call, and then come back to the laundry task again.