Any time you step outside of the simplest skincare regimen—whether you’re in pursuit of a good anti-aging approach, a thorough shave, or a potent exfoliant—you run a small risk of irritation. Everyone’s skin is different, and the more intense and active your products’ ingredients become, the more proactive you need to be in order to mitigate adverse reactions on your skin. Put another way: that product that makes that dude on Instagram look amazing might leave you a red and irritated ball of regret.
It’s not just in the advanced products that you run a risk. You might experience irritation from something as simple as a bar of soap, a cleanser, or shampoo (if their cleansing powers are a bit too powerful).
There’s one simple way to gauge whether or not your skin will have an adverse reaction to any product: It’s called the spot test, or the patch test. It’s done by applying the product to a less noticeable, small patch of skin, to see what it does with your specific skin’s chemistry. It’s simple, but you have to be patient, because you likely won’t get an instant result.
GQ spoke with a bona fide dermatologist to learn about the types of reactions your body can have to skincare products, as well as how to properly (and patiently) administer patch test prior to any use. And, though you may have buyer’s remorse for an expensive, advanced product that irritates your skin, it’s much better than the physical agony of having a reddened, painful face, right?
There are two types of adverse reactions—one slow, one fast.
Board-certified dermatologist Carly Roman, of Seattle’s Modern Dermatology, clarifies that there are two ways for a product to irritate your skin. “The first is an irritant contact dermatitis, which happens quickly—within minutes to hours of exposure. The second is an allergic contact dermatitis, which takes repeated exposure to the product and days to develop—at least 4 days.
That’s an important distinction—you may not be allergic to a product if you’re simply having a reaction to it. And if you’re experiencing a reaction and yet there is no new product in your regimen, it could be a slow-build response. Similarly, you might experience a reaction because of one-off factors. For instance, if you’re sweating a lot and it dries on your face, you may experience a reddening reaction to a peeling ingredient like salicylic acid or retinol. For this reason, it’s important to only apply products to freshly cleansed skin.
Not all reactions are the same.
These reactions can manifest as a variety of ways—reddening, dryness, itching, peeling, burning, blistering, and swelling. All bad, right? Basically, it’s when your products are making your skin worse, rather than better.
Irritation can come from anywhere, but there are also a few common sources.
The most common culprits when it comes to the irritant (non-allergic) contact dermatitis, are, roughly in order: Retinols, acids (particularly those found in chemical-powered exfoliating products), hair and beard dyes, alcohol, antiperspirants, and harsh cleansers, shampoos, and soaps.
Meanwhile, some of the more common ingredients that cause allergic contact dermatitis include preservatives like lanolin oil (as well as those impossible-to-pronounce ingredients like phenoxyethanol or methylchloroisothiazolinone), as well as fragrance, or benzophenone (a UV-filtering product found in many SPF-packed cosmetics).
Those lists include some good stuff that you’re not going to want to simply avoid. Instead, patch test your new products to be sure they’ll work for you.
Here’s how to test new products on your skin.
Roman suggests introducing just one new product per week, to reduce the chance of irritation and to be able to identify the culprit in the event that a rash does occur.
To actually perform the spot test, “I usually recommend patients test products on a small area such as the slide of the neck or inner arm,” she says. “To be thorough, the product would be tested for at least four days to determine if a delayed reaction (delayed hypersensitivity reaction) develops. There are some products in which irritation is a common side effect, like retinol, so we have patients start them slowly, two or three times a week, and reduce the frequency if their skin becomes dry or irritated.” In some cases (like with retinol), this momentary sensitivity can often be overcome once the skin acclimates.
Once you have confirmation that the product or ingredient doesn’t irritate your skin, you should be safe to apply it to your face or body, as directed. If you do experience an adverse reaction, it’s time to move on, or talk to your dermatologist.