Is Your Acne Product Aging You?

As if having acne wasn’t stressful enough, there is now compelling scientific data that shows benzyl peroxide, a popular acne treatment, could also be making us age faster. Let’s understand how this product is made to learn more of how it works on the skin.

Chemistry 101

Benzyl peroxide is usually prepared by treating hydrogen peroxide with benzoyl chloride. The oxygen-oxygen bond in peroxides is weak, so, benzyl peroxide readily undergoes homolysis (symmetrical fission), forming free radicals:

[C6H5C(O)]2O2 → 2 C6H5CO2•]

The symbol • indicates that the products are radicals; i.e., they contain at least one unpaired electron known as a free radical. This is an electron that doesn’t have a buddy and so it’ll latch onto anything that lets it have a friend. Electrons like to be in even numbers: 0, 2, or 8. If there’s an odd number of electrons (like 5), then obviously you have some number of paired electrons (in the case of 5, you have two pairs), and one left over. It’s that one left over that will now try and steal an electron from a neighboring molecule to stabilize itself. Such species are highly reactive.


Once this free radical forms and it succeeds in gaining another electron from a nearby molecule, it leaves its victim short an electron and has now made this new molecule, a free radical, which in turn, will try and steal an electron as well. And so begins an enormous chain reaction of free radicals that quickly wreaks havoc on living tissue. It is estimated that a chain reaction can trigger 6.023 x 1021 billion molecules to react per second.

How benzyl peroxide works on acne

Acne blemishes are usually filled with oil, bacteria and dead skin cells. Treatments to help this skin condition are designed to breakdown the debris and clean it out. It’s the hydroxyl radicals that are often referred to as the “detergent” in these formulas because they often react with pollutants forming the first step in their removal. Additionally, these free radicals have strong bactericidal activity that works to kill any present bacteria. You will sometimes see an antioxidant like green tea in a product containing benzyl peroxide, manufacturers put it in there as an antioxidant to help counteract the free radical activity. However, we have to ask ourselves, it is enough antioxidant activity to quench the damaging effects over time?