Don't Mix: Benzoyl Peroxide and Retinol
If you've been dealing with acne for a while, you probably already know that both of these ingredients work to prevent breakouts. But there's a good reason they're not often used in combination in the very same product. "Benzoyl peroxide is a potent acne product that's great for inflammatory acne, but many people are unaware that benzoyl peroxide can inactivate a topical retinol," explained Dr. Imahiyerobo-Ip.
This doesn't mean that you cannot use benzoyl peroxide during the same period that you're using retinol; it just means they should never be layered on top of each other or you'll be in for a rude (and red) awakening. Dr. Imahiyerobo-Ip recommends using benzoyl peroxide in the morning and a retinoid at night.
Mix: Retinol and Glycerin
Retinol is a miracle skin-care ingredient, but it's also pretty drying. That's why dermatologists and estheticians urge their patients and clients to use it sparingly. It's also recommended to use a bit at a time until skin is accustomed to it and stops peeling from it. One ingredient that can help prevent irritation when using a retinol-containing product is glycerin, a powerful humectant that helps draw water to the skin.
"When used together, they work synergistically to combat the signs of aging while also moisturizing the skin to minimize the irritating effects of retinoids," said Dr. Imahiyerobo-Ip. A great product that combines the amazing benefits of a retinol with the moisturizing benefits of glycerin is Hydropeptide's Nimni Cream ($110).