Q: I have a drawer full of skin care products of dubious age. Do they expire? And if so, are they still safe to use?
Unless the product is classified as a drug, as acne treatments and sunscreen products are, you probably won’t find an expiration date on it, said Dr. Bruce Brod, a dermatologist at Penn Medicine.
The item might display a “period after opening” symbol — or a tiny icon of an open jar containing a figure like 12M or 18M, which denotes the number of months a product is suitable to use after it’s opened. But that labeling is not required on skin care products or cosmetics either, Dr. Brod said. And even then, it won’t help you if you can’t remember when you opened it.
If skin care products are so old that you have forgotten when you bought them, you should avoid using them, Dr. Brod said. “It’s always better to be safe than sorry,” he added, since applying products that are past their prime can come with risks.
The dangers of using old skin care products
Once opened, skin care products can degrade and become overrun with microorganisms, depending on how they’re used or stored, said Elisabeth Anderson, director of science communication for the Center for Research on Ingredient Safety at Michigan State University.
When a product comes in a jar you must continually stick your fingers into, for instance, it can become contaminated with germs like bacteria or fungi, she said. And when those products are exposed to moisture, as they often are in bathrooms, those microbes can easily multiply.
If they are applied to the skin, this can result in irritation, eczema and skin or eye infections, said Dr. Anne Chapas, a dermatologist and fellow of the American Academy of Dermatology.
“Something gets into your cream, and you’re directly putting it onto your face, which could have a scratch or abrasion. And then, suddenly, that’s a nidus for a facial infection, which can be quite serious,” she said.
Skin care products usually contain preservatives to help prevent infection, Dr. Chapas said. But the preservatives can break down and become less effective over time — especially when stored in humid bathrooms or in direct sunlight, Ms. Anderson added. And products without preservatives, like those with “preservative-free” claims, can be at higher risk of growing bacteria, Dr. Brod said.
Another issue is that active ingredients can break down, especially when exposed to air and light, Dr. Chapas said. For instance, vitamin C oxidizes easily, causing it to degrade. Acids, like hyaluronic acid, can also become more concentrated when water in the product evaporates, possibly causing irritation, so she recommends not using them beyond a year.
Oxidation or degradation of ingredients isn’t always harmful, but it can make them less effective, Dr. Chapas said. “Even if it’s not going to be harmful to you, it might not be that beneficial to you either,” she added.
Products containing sunscreen or acne treatments should not be used past their printed expiration dates for this very reason, Dr. Brod said.
He also mentioned that products with tea tree oil or other essential oils can be harmful — possibly causing allergic contact dermatitis, a rash stemming from an immune reaction to something touching your skin — if they’ve been exposed to light and air for too long.
How to tell if a product is safe to use
The only way to truly tell if an older skin care product is safe to use is to have it lab tested for bacteria, Dr. Chapas said. But considering most of us don’t have science labs in our bathrooms, there are some clues that signify possible degradation.
One clue is if its emulsion, or mixture of oil and water, is separated, according to the Food and Drug Administration. Products might also appear discolored or have a change in texture, such as being dried out or gloopy. If something seems off, don’t use it, Ms. Anderson said.
Another sign that bacteria or other organisms have overgrown is if products smell bad or different than they should, Dr. Brod added. “That’s a red flag that a product may not be safe,” he said.
After opening a new serum or moisturizer, write the date on it with a marker or on a piece of masking tape, Ms. Anderson said. Also, note if there’s an expiration date or PAO symbol on its packaging. Then, “you have an excellent estimation of how long the product will remain in its optimal form,” she said.
Generally, most skin care products are safe to use for six months to a year, although maybe a bit less for eye products, Dr. Chapas said.
But when in doubt, toss it, she said. This can be hard to stomach, especially if the product was expensive, Dr. Chapas added, but “it’s not worth getting an eye infection” to avoid throwing it out.