A duo pack of our two best-selling serums to brighten and hydrate Vitamin C and hyaluronic acid work together to maximise the benefits of each other When the two ingredients are combined they become even more effective When applying together, we advise you to use the thinnest formulation first, followed by the thickest If you want to use one at a time, we suggest using Vitamin C in the morning and hyaluronic acid in the evening Cruelty Free