An Alchemist makes a love potion, we are told this is nonsense, but we say no it is true. Then the modern scientists discover the chemicals we use in them, like oxytocin, which we named something completely different. It doesn't mean that they just invented it, or discovered it, because they gave it a new name.
What makes a modern day 'love potion' any more real than one that is thousands of years old? It is less potent, because the truth is, they still don't know all our secrets, and likely never will.