It’s not uncommon for people to keep beauty products long after these items are past their prime without realizing they have shelf lives.

According to Jessica Wu, MD, an assistant clinical professor of dermatology at the University of Southern California, most beauty products are designed to stay fresh and stable for a limited time. Failure to routinely update makeup collections can result in products not working to their potential and even threatening health as bacteria can hide in containers and cause infections.

The best way to avoid any issues is to regularly go through cosmetic products, discarding old merchandise and buying new items when necessary. This can be done every few months or at the start of the new year. The following is a listing of the shelf life of many popular items and when to replace them.

Unopened products: If you have some cosmetic products that haven’t yet been opened, they might remain stable for a couple of years at room temperature, according to chemists at Cosmetech Laboratories in New Jersey. Air can cause formulas to oxidize, and germs can be transferred to products when they are touched.

Eye products: Mascara and eyeliners make contact with the eye, an area of the body that is sensitive and vulnerable to infection. These items should be discarded every three to six months to prevent bacteria formation. As they are often sharpened, eyeliner pencils have longer shelf lives than mascaras.

Foundation: Liquid foundations last around a year. Storing them in a cool, dark place will help them last even longer. After a year, the foundation could separate and its consistency may change. When applying foundation, avoid using your fingers, which can cause bacteria to grow more quickly.

Body brushes and loofah sponges: Acne and infections on the body may be a result of products and beauty items that are kept in the shower. Constantly being wet and in a warm, dark place makes them the perfect breeding grounds for bacteria. Discard these items every few months, and make sure they’re washed out and allowed to dry completely after each use.

Lip gloss and lipstick:

People run the risk of mouth sores by using old lipsticks and lip glosses. Bacteria can easily be transferred from the mouth to these items. Generally speaking, it’s a good idea to discard lip products between six months to a year after purchase. What’s more, color changes can occur, and the products’ quality may begin to degrade.

If makeup and other cosmetic products have been sitting around for a while, it’s likely time to buy a new collection to maintain safety and function.

– Courtesy Metro Creative