I tell my patients that acupuncture has a cumulative effect and that scheduling a series of treatments is the most effective way to help resolve imbalances. Why is this so? The endorphin theory.

Bruce Pomeranz, M.D., PhD., a neurophysiology professor at the University of Toronto School of Medicine and one of the world’s foremost acupuncture researchers, has reviewed more than a dozen studies on the effectiveness of acupuncture.

To challenge the belief of many conventional doctors that acupuncture simply produces a placebo effect, Dr. Pomeranz spent 20 years trying to disprove his hypothesis that acupuncture blocks pain pathways in the brain. Put another way, the question was, does acupuncture stimulate peripheral nerves that send messages to the brain to release endorphins (morphine-like compounds)?

A Chinese student working in his lab studied acupuncture as anesthesia on animals. If it was a placebo, then it should not work, he reasoned, because  placebos only work if the patient is conscious. The student had previously observed that acupuncture worked on farm animals and infants, who cannot experience the placebo effect. His experiments on anesthetized animals demonstrated that what acupuncture actually does is block pain pathways.

In testing the acupuncture-endorphin theory, Dr. Pomeranz tested 16 lines of evidence with 16 different kinds of experiments based on 16 different assumptions—all supporting his hypothesis. He concluded that there was more evidence in favor of the acupuncture-endorphin hypothesis than there is for 95% of conventional medical treatments.

Dr. Pomeranz says the advantage of the endorphin theory is that you can improve acupuncture treatment. Endorphins have a cumulative effect. The first treatment is mildly effective, the second, if given within hours or days, is even more potent. Endorphins have a memory. If you give an acupuncture treatment a third time in close succession, it’s going to be even stronger.