The rule of thumb when applying skin care products is THINNEST to THICKEST. Depending on your glycolic acid (is it serum based, pad, etc?) If it is a pad- I would do glycolic pad, vitamin c, TNS, and then HA5 (then sunscreen of course). But again- thinnest to thickest is the best way to go...
TNS Essential Serum has 2 chambers: one holds the growth factor formula (red color) and the other holds the serum including lots of antioxidants (cream colored). The antioxidants can be quite active, and for more sensitive skin can be irritating. If my clients have the symptoms...