Norwest Wellbeing

The 90% smoking-hypnotherapy success claim

Moderate evidence

“Quit in one session with 90% success” is a marketing line. Cochrane’s 14 RCTs do not support it. Uncontrolled clinic reports are not that evidence.

Last reviewed 27 August 2026

Contested claim: “Quit smoking in one session with 90% success.”

That figure is a clinic-marketing line, not a finding from the randomised trials in Cochrane 2019. Those 14 studies do not demonstrate a greater long-term benefit than other support or no treatment. Most did not find significant differences at six months or longer.

Key evidence

Cochrane’s included trials are small, mixed, and often unverified. They are the wrong pile from which to extract a 90% one-session rate. The plain-language summary says there is no clear evidence that hypnotherapy is better than other approaches, and that any benefit is small at most.

Uncontrolled clinic reports can count whoever completed a session and said they had stopped. Without a control group and without carbon monoxide or cotinine, that percentage is not a trial result.

Viswesvaran and Schmidt 1992 is sometimes used to dress older hypnosis numbers in “science.” That paper is a broad methods comparison. It is not a 90% trial, and Cochrane does not use it as the benchmark.

Limitations

This page names the claim, not every vendor who repeats it. A different percentage on a treatment page is still not Cochrane evidence.

What we don't know yet

What any one clinic’s internally tracked quit rate would be under biochemical verification and 12-month follow-up is a research question for that clinic. It is not answered by a slogan.

This page is informational only. It is not personal medical advice.

Headshot of Rebecca Smith

Reviewed by

Rebecca Smith

Dip.Clin.Hyp. Women's Health Specialist

Clinical HypnotherapistWomen's Health Specialist