Taking a fake supplement (actually a placebo) for 3 weeks can lead to both physical and cognitive improvements in older adults: this is the power of the placebo effect revealed by research conducted by psychologists at the Università Cattolica at Milan; the placebo works even when the persons taking it is aware of what they are actually taking. The study was published in the International Journal of Clinical and Health Psychology and led by Diletta Barbiani, Alessandro Antonietti, and Francesco Pagnini, and was funded by PNRR grants from the Age-IT project.
“The study is part of an established line of research in which we analyze the role of the mind in aging processes, which is very important,” Pagnini, Full Professor of Clinical Psychology at the Faculty of Psychology of the Università Cattolica emphasizes.
No study had yet examined whether a placebo in its traditional sense—an inert treatment presented as active—could influence functions that tend to decline naturally with age. “Our goal,” Professor Pagnini explains, “was to clarify whether an open-label placebo therapy (i.e., where the recipient is aware it is a placebo) or a fake supplement (people don’t know it’s a placebo) could influence psychological, cognitive, and physical functions in older adults living in the community.”
The researchers enrolled 90 healthy older adults, randomly assigned to one of three conditions: a control group that received no intervention; a deceptive placebo group that received placebo pills while being told they contained active ingredients effective in improving function and well-being; and an open-label placebo group, explicitly informed that the pills were inert but capable of inducing beneficial mind-body responses. Participants completed self-report questionnaires (providing information on levels of perceived stress, psychological well-being, sleepiness, fatigue, optimism, self-efficacy, and stereotypes about aging) and objective tests of short-term memory, selective attention, and physical performance before and after the 3-week intervention.
It turned out that after 3 weeks, the open-label placebo group showed lower levels of perceived stress compared to both the sham placebo group and the control group. Short-term memory performance also improved significantly in the open-label placebo group compared to the controls. The analyses revealed consistent cognitive and physical improvements in both placebo groups, with particularly pronounced effects in the open-label placebo group. Specifically, researchers found that the placebo improved physical performance by 7% when taken under deception, and by 9.2% when taken knowingly. Cognitive performance improved, depending on the assessment test used by the psychologists, by between 12.6% and 14.6% in the case of the sham supplement (deceptive placebo), and by between 6.9% and 21.5% in the case of the placebo taken knowingly. “These are significant effects,” the psychologist emphasizes, “comparable to those seen in some experimental studies on physical activity regarding physical performance and cognitive training, especially with regard to memory.” Among the various effects observed, there was an improvement in drowsiness and, particularly for the group aware they are taking the placebo, in stress levels.
Placebo interventions improved multiple functional domains in older adults, with open-label placebos producing benefits comparable to or greater than those of sham placebos. These results suggest the potential of open-label placebos as a promising and ethically acceptable approach to promoting healthy aging. These findings are another piece in the scientific literature demonstrating how the role of the mind—understood as thoughts, emotions, and self-perception—is extremely relevant in the aging process—not only regarding psychological well-being, which is quite intuitive, but also regarding physical and cognitive function, professor Pagnini concludes.
Experimental study
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Placebo mechanisms in aging: A randomized controlled trial comparing deceptive and open-label placebos on psychological, cognitive, and physical functioning in older adults
21-Mar-2026