The placebo effect can genuinely reduce pain.

It is easy to dismiss placebo responses as 'all in the mind' or mere reporting bias. But for pain specifically, the effect is one of the best-documented mind–body phenomena in medicine.

As Wager & Atlas (2015) review, expecting relief triggers real neurobiology: brain-imaging studies show placebos change activity in pain-processing regions, and placebo analgesia can be partly blocked by naloxone, a drug that blocks the body's own opioids — evidence of a genuine physiological pathway. Placebos do not shrink tumours or mend broken bones, and much of what looks like a placebo response in trials is actually natural recovery. But for subjective symptoms like pain, expectation measurably changes the experience. The claim is supported, with the crucial caveat that it works on perception, not on the underlying disease.