Highly-Stable, Water-Free Solution of 0.5% Pure Retinol, This water-free solution contains 0.5% pure Retinol, an ingredient that can reduce the appearances of fine lines, of photo damage and of general skin ageing. While Retinol has been studied extensively, it is irritating to the skin and newer technologies exist that mimic the visible effects of Retinol without causing skin irritation. For this reason, we generally recommend using Granactive Retinoid 2% or Granactive Retinoid 5% instead of this formula. Refrigerate after opening