You're correct that concentration is important. "The dose makes the poison", as they say. But it's not about being "comforting", it's about having a heuristic

You're correct that concentration is important. "The dose makes the poison", as they say. But it's not about being "comforting", it's about having a heuristic to make decisions when you don't have enough hard data. So in general, I try to avoid novel chemicals. It's not a guarantee of anything, but it's good enough for first-pass decision-making.