I think this is not really a charitable take. For one, nearly everything medical needs certain purity and concentration so you need specialized equipment. For two, even if a chemical is easy to produce by industrial standards, you still need to run trials to prove that it's both safe and actually does what you hope it does.

I wonder what the distinction here is between supplement and pharmaceutical.

Could they have chosen to bring it to market as a supplement?

They could have, but they would have been seen as just another “weight loss supplement”. Which I imagine is a real uphill communication battle to convince people that you’re just not another scam.

Supplements are often marketted with results from clinical trials; although typically not very rigorous trials.

Raising money to do clinical trials doesn't indicate the path to market.

I expect it has to be injected. Can you sell injectable supplements?

Well Trump just pardoned Ross Ulbricht who sold unapproved injectable drugs, so you can at least get away with shipping them into the United States, as long as you're not Mexican or Canadian.

Having to run trials has little to do with the whether the compound is naturally occurring and everything to do with the fact they intend to market it as a drug with specific effects