Shop Sienna Miller’s Favourite Retinol This Amazon Prime Day

Sienna Miller has long been admired for her laid-back beauty and perfect skin that looks effortlessly luminous. So—it’s safe to say it raised more than a few eyebrows when the actor recently mentioned that she swears by A313, a thick, pharmacy-grade retinoid cream quietly beloved in beauty circles. It’s a no-frills French formula, housed in an old-school metal tube, and while it doesn’t come with glossy packaging or a buzzy brand campaign, it’s earned cult status for a reason.

Unlike harsher prescription retinoids, A313 uses a blend of vitamin A derivatives that gently nudge the skin into glowier, smoother territory without causing chaos in the process. Miller described it as a tip passed along by a friend—Alexa Chung, no less—and noted how effective it is despite its humble price tag. It’s exactly the kind of product that’s easy to overlook until you hear someone like Miller casually name-drop it as part of her routine.