 It's the fact that certain products like chemical exfoliants or retinols contain active ingredients that are just too harsh for people in this age group. Preteen skin is much thinner. It is more sensitive to those chemicals. These products are designed ultimately for older people. So what can happen to these preteens is that their skin barrier, their stratum corneum gets compromised. So their skin is more sensitive and prone to irritation. So clearly preteens,