Open-label placebo pills improved memory in healthy older adults within just three weeks, even when the participants were told outright that the pills contained no active ingredients. New research from psychologists at the Universita Cattolica in Milan found measurable gains in memory, physical performance and stress after a short course of pills that everyone knew were fake, challenging the assumption that a placebo only works through deception.
How the open-label placebo study worked
The study, published in the International Journal of Clinical and Health Psychology, recruited 90 healthy older adults and randomly split them into three groups:
- A control group that received no treatment at all
- A deceptive placebo group told the pills contained active ingredients to improve well-being and physical function
- An open-label placebo group openly told the pills were placebos that could still trigger beneficial mind-body responses
Before and after the three weeks, participants completed questionnaires on perceived stress, psychological well-being, fatigue, sleepiness, optimism, self-efficacy and attitudes about aging. They also took objective tests of short-term memory, selective attention and physical performance, giving the researchers both subjective reports and hard measurements to compare.
Memory, stress and movement all improved
Participants who knowingly took placebos reported lower stress than both the deceptive group and the no-treatment control, and showed significant short-term memory gains compared with those who got no intervention. Both placebo groups improved on cognitive and physical measures, and in several cases the open-label group, the people who knew the pills were inert, posted the strongest results.
- Physical performance rose 7% in the deceptive group and 9.2% in the open-label group
- Cognitive scores improved 12.6% to 14.6% among those who believed the pill was real
- Those who knowingly took a placebo improved 6.9% to 21.5%, depending on the test
- Drowsiness decreased in both placebo groups
"These are significant effects, comparable to those seen in some experimental studies on physical activity and cognitive training, especially with regard to memory," said Francesco Pagnini, who led the work with Diletta Barbiani and Alessandro Antonietti.
Why open-label placebos matter for healthy aging
The headline result is ethical as much as scientific. Open-label placebos performed as well as, and sometimes better than, deceptive ones, which means clinicians could potentially harness the effect without lying to patients. That removes the central ethical objection that has long limited placebo use in real care.
The findings add to a growing body of evidence that thoughts, emotions and self-perception can shape both mind and body, and that expectation alone can move objective measures like memory and movement. The researchers frame open-label placebos as a low-cost, low-risk strategy worth exploring for supporting cognition and well-being in later life, though larger and longer trials will be needed before any clinical use. For more, see our health coverage and the latest science news.
Open-label placebo study: key questions
Can a placebo work if you know it is fake?
Yes. In this study the open-label group was told the pills were inactive, yet they showed gains in memory and physical performance and the largest reductions in stress, sometimes outperforming the deceptive group.
How big were the improvements?
Physical performance rose 7% to 9.2%, cognitive scores improved 12.6% to 14.6% among believers, and people who knowingly took placebos improved between 6.9% and 21.5% depending on the test, all within three weeks.
