Studies suggest that some manufactured chemicals are "sensitizing allergens," meaning they can prompt people to develop new allergies to certain makeups, creams, or perfumes they use repeatedly over time.
But just because something is "all-natural" or plant-based doesn't mean it's better.
Natural labels don't mean much in the first place, but more importantly, people react to all kinds of compounds — natural or not — in different ways. Take chamomile, for instance: some people are fatally allergic to the plant, which is a ragweed relative.
"Just be aware of certain things, because everyone's different," Batis said.
He believes no one is innocent in the beauty market: Companies could be more transparent about what's in their products, regulators should insist on third-party testing, and consumers may need to manage their expectations about what beauty products can reasonably do.
"I don't believe in the super duper crazy miracle," Batis said. "I believe that there's a great way to nourish the largest organ of your body."