The Biggest Signs Your Eyeliner Is Expired

Whether you like a pronounced wing or a barely-there eyeliner look, finding the perfect eyeliner can be like looking for a needle in a haystack. So when you find the rare combo of a brand, formula, and shade that you love, it can be tempting to hoard it. Buy one, get one sale? Better purchase four. Style being discontinued? Buy as many backups as you can! Unfortunately, this strategy can have a pretty serious downside. Namely, the risk of exposing your precious eyes to expired products.

If you weren't aware, different makeup items all have different periods when they're considered safe and effective. If you look at your cosmetics, you can probably spot the use-by symbol, which resembles a tiny makeup jar. Also known as a PAO symbol (for "period after opening"), this little line-art jar will have an abbreviation indicating how long the product can be used once opened (via Insider). For example, the abbreviation 3M means it can be used for three months, while the abbreviation 24M means it has a solid two-year lifespan.

But what if you don't use it all in time? Expired makeup products may begin to lose their effectiveness and potency (via The Ohio State University). In other words, you won't get the same coverage, vibrance, or pigmentation as when the product was fresh, undermining your overall makeup look. Worse, continuing to use expired products — like that favorite eyeliner you stocked up on — can cause ongoing health issues.

The sad truth is that all makeup products have a limited shelf life. Emulsions may separate, ingredients may degrade, mold may take root, and oxygen can get into cosmetics containers, causing oxidation. And while we might prefer to think that our face and skin are relatively sanitary, the truth is that we play host to a whole microcosm of bacteria and microbes. "We have a normal flora of bacteria on our skin and eyelashes that just hang out there on a regular basis, but they get introduced into our products through makeup brushes, wands, or other applicators," optometrist Johndra McNeely tells HuffPost. "Bacteria and fungus can grow in the product itself and then get reintroduced to the eye or face when putting makeup on over time."

In fact, eye products are among the most dangerous makeup items to use beyond their expiration. This is because you risk spreading harmful bacteria to your extra-vulnerable eyes, especially through liquid products. These bacteria can cause mild to severe infections, including nasties like styes or conjunctivitis — a.k.a. pink eye (via All About Vision). Symptoms of makeup-induced eye issues can range from pain and swelling to discharge, light sensitivity, and blurry vision. "Using old eyeliners can irritate the delicate eye area, causing it to become puffy, red, and swollen," Kelli J. Bartlett, artistic director at Glamsquad, tells The Healthy. So how can you recognize and weed out expired products before your eyes fall victim to these symptoms?

While solid items like pencils or gel eyeliner are considered safe for use for up to a year, liquid products are only deemed safe for a mere three months (via Mayo Clinic). Why? Because the way you use them can spread bacteria easier. Unlike typical makeup brushes, which stand alone and can periodically be washed, many liquid eye brushes can't be cleaned without wasting product. On the other hand, gel eyeliners usually come in pots with separate applicators. And as for eyeliner pencils, the very act of sharpening them helps peel away bacteria-exposed layers.

So, based on these timelines, you can keep a look out for any eye products that seem to be nearing the end of their safe shelf-life. Certain signs will indicate that it's time to throw your eyeliner away immediately. But what, exactly, should you be looking out for? When it comes to liquid liners, toss them pronto if the formula begins to noticeably thicken and clump. Do the same if you detect any unusual smells, including a sickly-sweet smell like dead flowers. For pencil eyeliners, keep an eye out for a white film that can't be sharpened away. Also, be leery of any unexplained oiliness or substances oozing from it (via Health). While it may hurt your heart and your wallet to trash quality beauty products, remember: your ocular health is more important than getting a perfect cat-eye, and there's always more makeup where that came from.