Confidence has been sold in bottles for centuries. I recommend the bottle with a label that reads “Scotch Whiskey.”
Well, technically you can buy all the poppy seeds you want. You’ll just get in trouble if you grow them. Or sell them as a “natural herbal remedy” via late-night infomercials.
What kind of snake? I mean, garter snakes are small and puny, but if it’s anaconda, then it might be worth something.
That’s understandable. How can you be confident if you have a squeaky snake? 
Food supplements are very lightly regulated. The ads are carefully written. As long as they dance around making any specific claims for the product’s effect, it’s still a supplement, for which the rules are lax. If there was a definitive claim of reducing anxiety, it would slip into the drug category, and the government would demand testing to back up the claim. Unless an herbal supplement is shown to be harmful, it’s hands off.