If you have a carton of milk in your refrigerator that's a bit past its expiration date, what do you do? You might sniff the milk to assess its freshness and decide whether to drink it or toss it. Usually, food expiration dates refer to the last date the item is guaranteed to be at its peak, as Consumer Reports notes. Drinking milk that expired a few days ago isn't likely to cause harm.
What about cosmetic products or drugs — or products straddling both categories? For instance, does mouthwash expire? You're likely to see expiration dates on some personal care, cosmetic and drug products. Should you pay close attention to when those products expire, or should you take the milk approach and use your best judgment when it comes to using or discarding the product?
Understanding Expiration Dates
As it turns out, the rules on expiration dates are a bit different for products such as mouthwash and toothpaste. While Consumer Reports notes that the expiration dates on food (with the exception of infant formula) aren't regulated, the Food and Drug Administration (FDA) does in fact regulate the expiration dates on any drugs or cosmetic products that can be categorized as drugs.
Personal care products that are regulated as drugs are ones that are formulated to treat or prevent a condition, notes the FDA. These products need to be tested for stability and need to have an expiration date printed on the packaging. When you look at an expiration date on a bottle of mouthwash, you have an idea how long the ingredients in the bottle will stay stable, meaning the FDA has identified how long the product itself will be able to work as intended.
Does Mouthwash Expire?
To better understand the expiration dates on mouthwashes, you first need to understand that the American Dental Association breaks mouthwash into two categories: therapeutic and cosmetic. A cosmetic mouthwash can help mask bad breath, but it's not going to correct dental concerns, such as gum disease, enamel wear or dry mouth. If you're looking for a mouthwash that helps control or correct certain problems, such as tooth decay, you'll want to look for a therapeutic mouthwash.
Therapeutic mouthwashes contain active ingredients and are regulated as drugs by the FDA. If you have an old bottle of therapeutic mouthwash lying around, it's particularly important to pay attention to the expiration date on it. If the bottle is past its prime, it's likely that the active ingredients have started to lose their effectiveness and won't be able to do the job as well as they could when the bottle was fresh off the shelf.
Although the FDA doesn't have as much control over cosmetic mouthwashes, you do still want to be cautious about the expiration dates on these. As with food, it's likely that a cosmetic mouthwash will decline in quality the longer it sits on your bathroom shelf.
What Happens If You Use Expired Mouthwash?
As the FDA explains, once the expiration date on a product has passed, there's no way to guarantee that it will be effective, because the ingredients may begin to break down and lose their efficacy. Although there haven't been studies looking specifically at mouthwashes that contain fluoride, a study published in Brazilian Oral Research examined the stability of fluoride in toothpaste. The study found that over time, the concentration of soluble fluoride found in toothpaste decreased, making the toothpaste less effective at fighting cavities.
Expired medications can also foster bacterial growth, as the FDA explains. Plus, medicinal products stored improperly — such as in a damp cabinet — can become less effective. For that reason, it's best to keep all over-the-counter and prescription medications in a cool, dark place.
So, does mouthwash expire? Yes, eventually — and especially therapeutic ones. If you find a bottle of expired mouthwash, your best bet is to discard it, or ask your pharmacist or dentist for advice. If your dentist has prescribed you a mouthwash to treat an oral condition, use it as directed before it expires, or contact them if you think you need a replacement.