We encourage people to ask “what kind of retinol” instead of “how much”. Our proprietary retinol compound is a blend of retinyl, retinol and a retinoid (all forms of Vitamin A). Concentrations in each phase of R45 The Reversal increase by 50%, so Phase 2 is 50% stronger than Phase 1, and Phase 3 is 100% stronger than Phase 1. The true litmus test of a retinol’s efficacy is color. Retinol in its raw form is yellow, so if it isn’t yellow, it doesn’t contain enough of this key active to work.