Charlotte Palermino on Instagram: "Brands, listen up!! This is why I recommend Differin before jumping to cosmetic retinols because Differin, prior to launching, had to prove through assay testing that nothing degrades and that product is stable. Also, it has proven claims for acne. OTC has a level of vetting that I love to see! Legally brands should be doing extended stability tests to get to claims, but I’m hardly the first person in the industry to point out products go off, some ingredients