Placebos aren't curative. It's well known that they can affect a subject's perception of how their condition is progressing, and this may have physical consequences: e.g. a reduction in psychological stress leading to reduced blood pressure, etc. But the placebo won't affect the underlying condition. They don't make the brain somehow cure the body.

Quote:

"Placebos won't lower your cholesterol or shrink a tumor. Instead, placebos work on symptoms modulated by the brain, like the perception of pain. "Placebos may make you feel better, but they will not cure you,"... "They have been shown to be most effective for conditions like pain management, stress-related insomnia, and cancer treatment side effects like fatigue and nausea."

https://www.health.harvard.edu/mental-health/the-power-of-th...