Sunday Riley A+ is a high dose retinoid serum with a 6.5 percent solution of stabilized retinoid blends and natural retinol alternatives. This is brand new, has never been opened, 1 fl oz. Sunday Riley doesn’t put expiration dates on their packaging, only “use within xx days of opening” dates. I purchased this within the last 9 months and it has been in its packaging, never opened, ever since. This was long my go-to retinol until some skin changes pushed me to try a different formulation, but I continue to recommend this product!