Moisturizer might be the most powerful product in your daily skincare arsenal. It’s the key to keeping your skin healthy, hydrated, and protected against the many factors that can contribute to premature aging. But its effectiveness may decline over time.

Like any skincare product, moisturizing creams, gels, and serums have a shelf life. Using these products after their expiration date might mean you’re not getting the maximum benefit your skin deserves. It could even irritate or damage your skin.

Let’s explore this subject further to determine the average shelf life of moisturizer, signs your product has gone bad, and tips to make it last longer.

Unopened moisturizers may last 2-3 years when stored properly in a cool, dry location out of direct sunlight. Opening the product drastically reduces its shelf life, however, but most products are still good for 6 months to 1 year .

How long a moisturizer will last depends on the formula. Products that contain certain active ingredients may have a shorter shelf life than basic face creams, so always check the container for each product’s “best by” date.

Even if you use your favorite moisturizer every day, you might not go through all of it before its expiration date passes. Here are some of those signs your moisturizer has gone bad:

• Changes in consistency . The product has changed from its original texture. Maybe it has become runny, watery, or even clumpy.

• Difference in color . Most moisturizers are white or cream-colored, so once a product starts to darken or turn yellow it’s usually time to purchase a replacement.

• Strange odor . Moisturizers run the gamut in terms of scent but if a scented product loses its aroma or an unscented product starts to smell sour or rancid, it may no longer be safe or effective.

• Reduced effectiveness . It may be harder to tell when your moisturizer stops working than with other skincare products, but if you have suspicions it’s best to pitch it.

If you notice any of these signs, it’s usually best to discontinue use of the product and purchase a replacement.

Skincare products are sealed to prevent oxidation and, once opened, they may begin to degrade. Moisturizers tend to have a higher water content than other skincare products, making them more susceptible to degradation and contamination with bacteria and other pathogens.

Expired moisturizer might be less likely to damage your skin than some skincare products, it could still cause irritation. Bacteria, mold, or degraded ingredients in the product could cause contact dermatitis, leaving your skin dry, itchy, and scaly or flaky.

However, the most likely scenario is that you won’t get the same benefits from a moisturizer past its expiration date.

In the realm of skincare products, moisturizers tend to be pretty low-maintenance. But there are a few simple things you can do to maximize the shelf life of your moisturizer (both before and after you open it):

• Store it in a cool, dry place . Keep your moisturizer out of direct sunlight and consider keeping it in a cabinet instead of on the vanity in your bathroom where it might be exposed to moisture.

• Check the package for a “period after opening” indication . Many brands indicate on the package how long the product is good for after being opened. It’s usually printed as a number followed by the letter M (e.g. 3M, 6M, or 12M).

• Make note of when you open it . The expiration date generally applies to the unopened product. If you aren’t sure you’ll use the product within 6-12 months, consider writing the date you opened it on the container.

Don’t dip your fingers into the jar . For products in tubs or jars, use a small spoon or spatula to dip into the product instead of your fingers. This helps prevent bacteria and oil on your hands from contaminating the product.