Just remember that the placebo effect is only effective in a small percentage of the population, and is consistent with any other substances that may induce this phenomenon. That’s how they know when something actually works…it works in the majority of people, not just that small percentage.
Yeah that’s not quite it. Placebo is actually present for most/the majority of people, but they (researched of various kinds )are looking for effects that are above and beyond the level demonstrated by the placebo alone.
One fun thing to think about is that most (maybe all) treatments include some degree of placebo effect inherently.