Can You Become Immune to Your Skincare?

Or is it all in your head?

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Scenario: You crack into a brand new serum and it's love at first application. The formula works miracles on your finicky skin and bestows your complexion with a seriously head-turning glow. Infatuated, you use the bottle religiously for several months...only to discover that your skin looks less glowy and not-so-extraordinary as the calendar pages flip. Are you imagining things or have you grown immune to your skincare?

Dermatologist Marnie Nussbaum M.D. says that it is possible for some ingredients in your skincare products to become weaker over time through tachyphylaxis, the term for an eventual tolerance to a medication. “When this happens, the body can alter the signaling pathways on a molecular level so that the product is no longer effective.”

This is why your product seemed to stop working.

But wait! Don't go tossing out your entire beauty arsenal just yet: “Tachyphylaxis is very uncommon with general skincare and usually only happens with topical steroids in conditions like psoriasis and eczema," says Dr. Nussbaum. "There are a multitude of factors that can explain why a product may seem less effective.”

You always get the most robust response to a product immediately upon first use, says Dr. Nussbaum. This means that over time, even though the product is still working, the visible results have diminished and may be more difficult to notice.

What's more, if you’re a serial skincare switcher-upper, you might be using a mix of ingredients that don’t play well together. “For example, benzoyl peroxide will oxidize vitamin C and therefore [those ingredients] should not be used together. Vitamin C and retinoids are better used separately (morning and evening) as they can become extremely irritating when used together,” advises Dr. Nussbaum.

Your environment could also be to blame. “As the seasons change and your skin becomes dry, it is harder and harder for your hardworking serums and lotions to navigate through the dead skin cells,” explains Dr. Nussbaum. “Changes in your external environment, such as increased exposure to cigarette smoke, household chemicals, or even the sun, can increase the free radical damage in your skin. This makes your products have to work double duty, making it look like there's less of a response.”

And some ingredients are special cases, like retinol. Says Dr. Nussbaum: “Most people think retinoids become less effective over time, but your skin is just becoming more tolerant of the ingredient”—think no redness or peeling. “The product is still working; you just aren't experiencing any adverse effects.”

Here's when you should switch up your routine.

Listen to your complexion. According to Joanna Vargas, celebrity facialist and founder of Joanna Vargas Salons and Skin Care in New York and L.A., “while products don’t really change, skin does. Therefore, the products you need to use will need to change over time.”

You might want to switch up your skincare as the seasons change, says Vargas. This includes switching from serums to lotions or lotions to creams during the drier winter months.

That being said, Dr. Nussbaum reiterates that as you add in a new ingredient, you need to be cognizant of bad product combinations. “It’s wise to separate powerhouse ingredients by a.m. versus p.m. application, in addition to alternating ingredients on a daily basis. That way, you can benefit from all the potent actives without worrying about them cancelling each other out, or the dreaded pilling effect of piling too much on at once.”

There are ways to ensure your products are more effective for longer.

According to Dr. Nussbaum, you should be exfoliating 1 or 2 times weekly to shed the layers of dead skin cells and allow the active ingredients to penetrate deeper. Always remove makeup and cleanse thoroughly before applying anything to achieve the best results.

“It’s also important to combat free radical damage as it can slow skin cell turnover, which results in dry, dull skin with increased fine lines and wrinkles,” says Dr. Nussbaum. As always, apply a broad-spectrum sunscreen of SPF 30 or higher year-round.

Keep in mind that certain ingredients can become less effective over time due to destabilization (i.e. opening and closing the lids each day), so avoid leaving your bottles in humid bathrooms. “Over time, and depending on how products are stored, active ingredients can separate or break down. Always store products in a cool, dry place and immediately close them after use.”

Most importantly, don't play skincare bartender. Always consult a dermatologist if you have questions about your routine—a doctor can streamline your skincare routine via an individualized approach that best matches whatever your needs may be.

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Hana Hong

Hana Hong is the beauty assistant at Marie Claire, where she covers skincare, makeup, and haircare, and is identifiable by her signature cateye.