A pre-registered trial of 293 healthy adults has found that giving people personalized feedback about their own progress did not strengthen the effect of an honest, or open-label, placebo, even though the placebo itself produced a measurable benefit on its own. The study, by Kirsten Barnes and Kate Faasse of the University of New South Wales, published online January 28, 2026 in the Journal of Health Psychology, randomly assigned participants to one of three groups over a 10-day period: an open-label placebo pill with tailored feedback on day 5 and day 10, the same pill with no feedback, or no treatment at all. Everyone in the placebo groups was told plainly that the pills were inert but might enhance wellbeing.
Open-label placebos are treatments given without any deception: the person knows, and is told outright, that the pill has no active ingredient. Decades of trials, starting with a small 1965 report on anxiety and given wider attention by a 2010 irritable bowel syndrome study, have found that these honest placebos can still produce real improvements in how people feel, a finding that has intrigued researchers because it does not rely on fooling anyone. The new trial set out to test one specific idea for making that effect stronger: showing participants interactive graphs and descriptive statistics of their own reported wellbeing, on the theory that seeing tangible proof of improvement might reinforce and amplify it.
The placebo pill did improve wellbeing overall, with participants who took it reporting fewer negative emotions and better sleep quality than those who received no treatment, and their expectations for improvement rose significantly over the 10 days. But the tailored feedback added no statistically detectable benefit beyond the placebo alone; the group that received feedback did not outperform the group that took the identical pill without any feedback. The researchers noted that expectations diverged somewhat more between the two placebo groups as the trial went on, and suggested that a longer trial with more frequent feedback might be needed to detect an effect, if one exists at all.
The authors are careful to frame this as an open question rather than a settled negative: their own paper states that more research is needed before concluding feedback has no role, and the practical implication they draw is that longer treatment periods with more feedback opportunities might yet produce different results. Independent methodological reviewers, writing separately in the journal Pain in August 2026, have flagged that open-label placebo research broadly still needs clearer standards for control groups and blinding strategies before firm claims can be made about what enhances or diminishes the effect.