Your Anti Frizz Serum is always best applied before you blowdry. The HairGoStraight Frizz Away serum that we use in my salon, must be used on damp, towel dried hair.
It is a thicker serum that needs heat to work. If you put it in your hair after, it may very well weigh down your hair as well as make it a little greasy. It aids in helping you dry your hair quicker, with less frizz. Happy no fuss Blowdrying !