We found that 11 percent of people in fibromyalgia drug trials who were taking fake medication dropped out of the studies because of side effects like dizziness or nausea. Other researchers reported that the discontinuation rates because of side effects in placebo groups in migraine or tension drug trials were as much as 5 percent. Discontinuation rates in trials for statins ranged from 4 percent to 26 percent. In a curious study, a team of Italian gastroenterologists asked people with and without diagnosed lactose intolerance to take lactose for an experiment on its effects on bowel symptoms. But in reality the participants received glucose, which does not harm the gut. Nonetheless, 44 percent of people with known lactose intolerance and 26 percent of those without lactose intolerance complained of gastrointestinal symptoms. In one remarkable case, a participant in an antidepressant drug trial was given placebo tablets — and then swallowed 26 of them in a suicide attempt. Even though the tablets were harmless, the participant’s blood pressure dropped perilously low.
If you do N=1 self-experiments on diet/supplements/exercise/sleep, don’t set your conclusions immediately. Make several non-consecutive trials so you cancel out variations in the many uncontrolled causes in your life.