Can Your Shampoo And Conditioner Expire?

We're not new to the idea of expiration dates. From cartons of milk to jars of salsa, we're accustomed to seeing these cautionary timelines printed on products. But while expiration dates get a lot of attention in our kitchen, many of us overlook them in regard to our cosmetics and toiletries. Unfortunately, beauty products aren't immune to the march of time. From mascara to nail polish, pretty much anything that goes on your body will have a limited lifespan. That's why it's important to recognize the signs of expired foundation, eyeliner, and other cosmetic products.

But what about your hair care favorites? Can shampoo and conditioner expire? Alas, they can. For proof, look no further than the bottles sitting in your shower. Upon close examination, you should be able to find a symbol on each product, resembling a makeup jar with an abbreviation inside. This is known as a PAO, or a "period after opening" guideline, and it will let you know how long a product is considered stable and safe for use once you've popped the cap (via the Obelis Group). For instance, if the PAO says "12M," you have 12 months before the quality may become questionable.

Of course, we've all had that half-used bottle of shampoo or conditioner lurking in the back of a cabinet or forgotten at the corner of the tub while we use other products. Is it really that big of a deal to pull it out of retirement after the PAO has passed? Well, that depends on whether you're willing to face the potential health risks.

As much as we hate to acknowledge it, beauty products only last for so long before they begin to break down. And once this occurs, you could be risking some serious consequences from continued use. For one thing, expired shampoo doesn't work as well, and your hair may continue to look dull or dingy even when freshly washed. "Expired products undergo a chemical change, which means they're no longer effective at a high level," Gina Rivera, stylist and founder of Phenix Salon Suites, tells Healthline.

Rivera goes on to explain that this chemical change can cause irritating symptoms like scalp itch when expired shampoo or conditioner hit your skin. Old products also have a tendency to attract mold and bacteria or oxidize as they're exposed to air. Applying such contaminated products to your hair can lead to a number of nasty scenarios, including scalp infections (via WebMD).

"There are many things that can happen when a product expires," cosmetic chemist David Petrillo tells RealSimple. "Many times the chemical components can separate. ... It can potentially be harmful as the ingredients were not meant to be applied in this manner or penetrate the skin separated." This can even lead to hair loss. But what if you stocked up on a favorite shampoo, and some bottles haven't even been used yet? If they've been sitting on the shelf for more than three years, you probably need to let them go. And if you're still not sure, there are some physical signs that your shampoo and conditioner may be goners.

As with any beauty product, one of the first signs that something is off with your shampoo is a change in smell. Many hair care products are scented in the same way as perfumes: with essential oils from pleasant-smelling plants (via Head & Shoulders). However, these formulations have a limited shelf life. So, if your shampoo or conditioner takes on a weird tang, it may indicate that something in your product is breaking down.

Another clear sign of trouble is a textural change. For example, if your product starts to separate or develop clumps within the bottle. Shampoos and conditioners often contain two or more liquids that don't naturally want to mix, such as oil and water, and beauty chemists have to balance the formula carefully by combining agents called surfactants to create the silky texture we expect (via Susteau). But, over time, this balance can degrade, leaving your hair products an unrecognizable mess. So, if you notice their texture changing or splitting, it's probably time to let them go.

Finally, pay attention to the hue of your shampoo and conditioner. If you notice them becoming discolored or yellow, something is afoot. While trashing expired products may feel like a waste of money, your health is worth a whole lot more. So whether your skincare routine has suddenly stopped working or you've noticed a funky, off-putting smell from your conditioner, pay attention to the PAO and shelf-life of your beauty products. Your skin and hair will thank you in the long run!