Mascara isn’t inherently dangerous, but it does carry real risks depending on the formula you choose, how long you keep it, and how thoroughly you remove it. The biggest concerns are bacterial contamination over time, ingredients linked to hormone disruption, and damage to the oil glands that keep your eyes moist. None of this means you need to toss your mascara today, but understanding the risks helps you use it more safely.
Bacterial Growth Starts Quickly
A fresh tube of mascara is rarely contaminated with bacteria. The problem begins the moment you start using it. Each time you pull the wand out and push it back in, you introduce bacteria from your lashes and the surrounding skin into a dark, wet environment where they thrive. The FDA notes that some industry experts recommend replacing mascara just three months after purchase because of this repeated microbial exposure.
The CDC has documented cases of serious corneal infections caused by Pseudomonas aeruginosa, a bacterium cultured from both a patient’s infected eye and her mascara tube, with identical antibiotic sensitivity patterns confirming the mascara as the source. That particular infection progressed rapidly and caused lasting damage to the cornea. While severe cases like this aren’t common, they illustrate why old mascara is a genuine health risk rather than just an aesthetic one.
As mascara ages and dries out, it also clumps and flakes more easily. Those tiny particles can fall into your eye, causing irritation or scratching the surface. If you wear contact lenses, flaking mascara is especially problematic because debris can get trapped between the lens and your eye.
What’s Actually in the Formula
The ingredients in mascara vary widely by brand and type, but several categories of chemicals found in common formulas have raised health concerns.
Waterproof and long-lasting mascaras are particularly likely to contain PFAS, a group of synthetic chemicals that resist water and oil. A 2021 study from the University of Notre Dame found especially high levels of PFAS in foundations, mascaras, and lip products. Exposure to certain PFAS chemicals has been linked to thyroid disease, liver damage, immune system effects, and reproductive complications, even at low levels. These chemicals are persistent in the body, meaning they accumulate over time rather than being quickly flushed out.
Many mascaras also contain parabens and phthalates as preservatives or texture enhancers. Both are endocrine disruptors, meaning they interfere with your body’s hormone signaling. Phthalate exposure has been linked to increased risk of breast cancer, decreased fertility, preterm birth, and cardiovascular problems. Some formulas use formaldehyde-releasing preservatives, which have their own cancer risk associations. The black pigment in mascara often comes from coal tar dyes or carbon-based compounds, and some of these dyes contain petroleum byproducts like benzene, a known human carcinogen.
The dose from a single application is tiny. But mascara is something many people apply daily, directly next to a mucous membrane, for years or decades. That cumulative, long-term exposure is what researchers find concerning.
How Mascara Affects Your Oil Glands
Your eyelids contain tiny oil glands called meibomian glands that produce the oily outer layer of your tear film. This layer prevents your tears from evaporating too quickly. When these glands get blocked or damaged, the result is chronic dry eye, a condition that causes burning, grittiness, and blurred vision.
Research published in the Saudi Journal of Ophthalmology found that mascara remnants can migrate onto the eyelid margin and obstruct these glands, interfering with oil delivery to the eye’s surface. The study found measurable gland loss in makeup-using groups. Interestingly, using mascara alone caused similar levels of gland obstruction as using mascara and eyeliner together, suggesting that either product on its own is enough to coat and block the gland openings.
The inflammation appears to happen regardless of exactly where you apply the product. Materials in eye cosmetics can affect gland function by triggering inflammation around the glands themselves, and lab studies show these products alter the molecular structure of the natural oils your glands produce.
Waterproof Formulas Carry Extra Risk
Waterproof mascara is designed to be completely impervious to water, which sounds like a feature until you try to take it off. The same tenacious adhesion that keeps it from running in the rain means it requires aggressive removal at the end of the day. That usually involves oil-based removers, soaking, and more physical contact with delicate eyelid skin than regular mascara demands.
Rubbing and tugging at your lashes during removal can irritate the eyes, stretch the thin skin around them, and pull out lashes over time. Wearing waterproof formulas daily can also lead to dryness and irritation simply from the formula sitting on your lashes all day. The stronger solvents in waterproof formulas are more likely to contain PFAS and other chemicals that give them their water-resistant properties.
Water-removable mascara washes off with ordinary soap and water, which means less friction, fewer harsh removers, and a lower chemical load overall. If you reach for waterproof mascara for a wedding or a pool day, that occasional use carries far less risk than making it your daily go-to.
Safer Ways to Use Mascara
Replace your tube every three months, even if there’s product left. This is the single most effective step for reducing infection risk. Mark the date you opened it on the tube if you tend to lose track.
Apply mascara to the tips of your lashes rather than working it all the way down to the root where lashes exit the skin. Keeping the product away from the lash line reduces the chance of it migrating into your eye or blocking the oil glands along the lid margin.
If you wear contact lenses, put your lenses in before applying mascara and choose a water-removable formula. Remove your mascara thoroughly every night. Sleeping in mascara gives dried particles hours to flake into your eyes and gives any product residue on your lid margin extended contact time with your oil glands.
When choosing a formula, hypoallergenic and ophthalmologist-tested products are less likely to contain common irritants. Avoiding waterproof and “long-lasting” claims reduces your exposure to PFAS. Products with shorter, simpler ingredient lists generally carry fewer chemical concerns, though no mascara is completely free of trade-offs between performance and safety.