No, I think it's perfectly fine to require a company to have to prove that their product does what they say it does, or at the least, require that they provide refunds when it doesn't. If I buy a PS4, I expect it to play PS4 games, and if it doesn't, I have 30 days to return it. If I buy a case of beer that says variety pack but it turns out to only contain brown ale, the store is going to let me return it.
Many of these supplement companies do have a money back guarantee, but they make it such a hassle to return the product that most people chalk it up as a loss. I don't mind them being allowed to make whatever claims they want about efficacy as long as they're required to take it back when it doesn't work.