What really happens if you use expired makeup

Expiration dates can be confusing when it comes to food — sometimes it's important to follow them, sometimes you can safely ignore them. But what about makeup? Do those expiration dates really matter? It may be tempting to hold onto that old tube of mascara, or the expensive lipstick you've been saving so long it might actually have been purchased in 2002, but the risks far outweigh the rewards.

Dermatologist Hadley King, M.D. spoke to Women's Health about why we should be paying just as much attention to the expiration date on our foundation as our milk. First up, the consistency of the product will deteriorate. "They're going to dry out, get clumpy and not apply as smoothly. That's true for everything from mascara to lipstick and foundation," King said.

You're also risking a bad reaction due to molecules in the products breaking down over time, which can lead to skin irritation and even inflammation. Expired makeup can harbor bacteria which, again, can lead to irritation, bumps on the skin, and even pink eye. Using expired lipstick can also cause swelling. 

It's recommended that you replace mascara every three months, eyeliner and eyeshadow every six to 12 months, and lipstick every 18 months. Foundation, powder, and any other facial makeup usually expires after about 12 months. 

Even unopened makeup can pose a health risk, as Jessica Mae, founder, creative director, and makeup artist of WarPaint International Beauty Agency, explained to Reader's Digest. Mae noted, "The [breakdown] process will happen more slowly, but once the product is exposed to air the same expiration effects take place. It is also possible that the preservatives start to break down even before you open it. So, if you stocked up on foundation and it's now been sitting unopened in your drawer for five years, chances are you should just throw it out even though it's unopened."

Watch out for warning signs, too. As Mae advised, "If the product starts to dry out, it's definitely time to replace it. In foundation, watch for if the product is separating in the container. For lipstick/gloss, if the color starts to change tone or you notice a change in the way it smells." You should also ensure your makeup isn't stored in the bathroom as hot, steamy showers could reduce its shelf life.

Always keep your brushes clean, too, by washing them once a week, to keep bacteria and additional oils from getting into your makeup. And, if you're ever in doubt, simply toss it out.