I know your not meant to but I'm so addicted to this product that I've been using it everyday.
I apply a pea-sized amount to cleansed, dry skin and leave to absorb. I then apply my make-up as usual.
I've been using it for 2 weeks and cannot get over how beautiful my 50-something skin is looking.
Clarins recommend that you use this only when your skin needs a boost, or as a facial mask for tired, dull skin, but I don't see why you can't use it everyday!