To help you achieve a healthy, clear glow, we asked skin-care insiders to reveal the ingredient combinations that lead to adverse effects when slathered together.
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.
Don’t Mix: Vitamin C And Alpha Hydroxy Acids
Both of these ingredients offer antioxidant benefits, but when combined, they can throw off the pH balance of your skin due to too high levels of acidity. Products containing vitamin C (L-ascorbic acid) as an ingredient contain low levels of acidity (typically a three on a scale of 14). When you use this kind of product along with an alpha hydroxy acid, like glycolic or lactic acid, you’re essentially reducing the effectiveness of the vitamin C product. Is it dangerous or irritating to combine them? Probably not. But you’ll be wasting a whole lot of what might be an expensive product if you do!
Don’t Mix: Vitamin B3 And Alpha Hydroxy Acids
Also known as niacinamide, vitamin B3 is a skin conditioning agent that helps repair and refine the skin’s structure. It tends to work best in an environment with a neutral pH, which we just explained is certainly not alpha hydroxy acids, as they have an extremely low pH level.
“When used in a product containing high levels of alpha hydroxy acids (i.e. glycolic, lactic,) nicotinic acid is produced, which may result in skin flushing and potential irritation,” explained Ramya Viswanathan, product development manager at Biossance. While it won’t necessarily harm you to use them both together, they basically cancel each other out.
Don’t Mix: Vitamin C And Retinol
Retinols and retinoids are powerful ingredients that address several skin-care concerns, from diminishing fine lines and wrinkles and preventing acne to lightening brown spots and increasing collagen production. This is why you’ll find a retinol-based product in many dermatologists’ skin-care routines.
“The main concern with retinol-based products is skin irritation,” said Dr. Imahiyerobo-Ip. “There are several active ingredients that may increase the chance of irritation with retinoids, one being vitamin C.” Like retinol, vitamin C is effective in combating the signs of aging, including fine lines, firmness, and uneven skin tone. However, when these products are used together, they may cause irritation in those with sensitive skin.
Don’t Mix: Alpha Hydroxy Acids And Retinol
Glycolic acid and lactic acid are both chemical exfoliants that help improve the skin’s texture, minimize pore size, and also help with brown spots, whereas salicylic acid is a beta hydroxy acid that controls oil production to help prevent pimples. Glycolic acid, lactic acids, and salicylic acids are often found in face washes in low concentrations.