I’m 55 and have used this on and off for the last decade, but steadily for the past 3 years. I never notice how much this helps my liner or lipstick stay and how neatly the application is until I’ve run out. You have to wait a few minutes before applying lipstick over the primer or it won’t work. Apply one thin layer, no more than that. Recently I’d noticed I can apply liner almost right away and then color my lips with that liner to create a base layer that becomes part of the primer - then lipstick a few minutes later. When my lipstick wears off the layer of liner is still visible for several hours. Now I rarely bother adding lipstick on casual days.
This is the third time I’m purchasing this lip primer. If you put it on and wait a couple minutes it dries down and then helps your lip liner and lipstick stay on so much longer. I love it.