"What, exactly, is chiropractic, and what would happen if its claims were subjected to serious scrutiny?"

"[I]mprovement after treatment is not always improvement caused by treatment, since much of it arrives with time and attention. ...

"[C]hiropractic [is] not one profession but many: true believers, entrepreneurs, technicians, philosophers, clinicians ... [but w]hat, exactly, [is] chiropractic, and what would happen if its claims were subjected to serious scrutiny? ...

"During the 1980s and 1990s chiropractic researchers launched clinical trials, comparative-effectiveness studies, and collaborations with universities and medical centres.

"Then, the larger, better-designed studies made the clinical picture go soft. Patients improved—sometimes substantially—but the improvement proved stubbornly hard to pin on [chiropractic] manipulation. Natural history, spontaneous recovery, reassurance, exercise, attention, expectancy, and plain contextual healing kept blurring the causal thresholds. Manipulation generally performed about as well as any other conservative care including placebo, and when superior, it closely tracked the false positive rate expected under null hypothesis significance testing. In fact, to this day you will see chiropractic research conclusions proudly assert that manipulation is no less effective than other treatments for low back pain, including controls—a damnation by faint self-praise. ...

"Look closer, though, and the chiropractic 'arm' was not manipulation but, in reality, the effect of repeated visits, education, exercise, reassurance, coaching, ergonomic advice, self-management support, and the whole atmosphere of attentive care. Patients improved; the contribution of [chiropractic] manipulation itself stayed unknown. And when mechanistic studies looked for the distinctive physiological signature—balance, postural sway, neuromuscular response—the effects were weak, inconsistent, or absent. The anticipated effects of chiropractic refused to show up.

"The strongest test arrived recently. In a trial published online in late 2025, a team led by Gert Bronfort reported on a thousand patients ... Over a year, [chiropractic] manipulation by itself was statistically indistinguishable from ordinary medical care on pain and disability—half a century of hope for the adjustment, tested cleanly at last, returning null. ...

"Chiropractic research is alive and well in Denmark, New Zealand, and a handful of other centres, often more rigorous than anything the reform years produced. But the results of more research will not make spinal manipulation more acceptable. It cannot rescue a treatment this marginal; it will only measure it more precisely. ...

"But a literature that will not resolve after enough well-powered attempts is not unfinished. It is null."

~ J. Michael Menke from his post 'An Insider’s Look at What Happened When Chiropractic Was Evaluated Scientifically, and Why No One Remembers'