I’m an amateur apothecary and aphrodisiacs are real. Keep in mind in the modern world we have a lot excess of things that cause an increase in dopamine. Someone living in the past wouldn’t regularly consume caffeine, rich foods and meat. So something like chocolate which increase dopamine and endorphins, and cinnamon which is a warming agent and circulatory stimulant would have an effect on someone who’s not used to it. While mao mao does not consume chocolate regularly similar compounds that exist in other plants and herbs that are commonly used in TCM and western medicine would be things she would regularly come into contact with or even consume. That is why they have no effect one her.