Dr Geraldine Moses from UQ's School of Pharmacy spoke with ABC News about the effects of collagen supplements and whether they lead to younger, healthier skin.
Collagen's popularity stems from its use in the 80s as a filler — it's injected into lips or cheeks to make them plump.
"That worked of course, but … swallowing stuff is not the way to go," Dr Moses says.
"Generally speaking, it doesn't get absorbed."
But regardless of efficacy, our desire for younger-looking skin is an advertising dream.
There is no obligation on a corporation's part to prove collagen's effectiveness; just as is the case with some beauty treatments, there is no industry regulation.
"These products are never tested, they never have to prove that they work, so we're putting blind faith into the industry," Dr Moses says.
"Manufacturers can make these claims and they know that they're not obligated to prove anything."
This is also the case with another beauty supplement, silica, she says.
"The scientific name for silica is silicon dioxide — and the everyday name for that is sand, which you find at the beach," Dr Moses says.
"Anyone who's been at the beach with a baby knows that sand will just go straight through you. There's no oral bioavailability."
Clinical studies on the bioavailability and efficacy of silica supplements for your skin are lacking.
Rather, the idea that silica has a benefit to hair, skin or nails in supplement form is "taking advantage of people's ignorance," Dr Moses says.
"[A silica supplement] is harmless in the sense that it's not dangerous to you.
"But there is harm in spending money you didn't need to spend."