I know the idea is to be snarky and calling them "new age" somehow makes them less than real science, but the reality is there is some amazing science that has been done that shows how these different chemicals influence our brains and our behaviors. Good video on the topic with in-depth explanations from real scientists:
HAPPINESS: A Guide to the Drugs That Can Help You Get There -> https://www.youtube.com/watch?v=zcAmgNoWzVk&t=29s
The scientist in the video: