25/03/2026
Quercetin has some of the strongest scientific merit of any antioxidant in skincare.
So why isn't it more widely used at meaningful concentrations?
Two formulation problems worth understanding.
Problem 1: Getting it into the formula. Quercetin is notoriously difficult to stabilise at therapeutic levels. Solubility is a real challenge - and at low concentrations, the biological impact is limited.
Problem 2: The yellowing effect. Apply a high-concentration quercetin serum, then layer a zinc-based sunscreen or mineral makeup on top, and your skin turns yellow. Not a reaction to worry about, but a visible cosmetic issue that makes it impractical for daytime use.
Which is why highly concentrated quercetin belongs in your evening routine.
Timing an ingredient correctly isn't a minor detail. It's the difference between a formula that works and one that doesn't.