Up to 90% of Used Makeup Products in One Study Contained Bacteria—Here’s What That Means
A study of used cosmetics found widespread bacterial and fungal contamination, particularly in damp makeup sponges. Here is what the research actually showed—and the simple habits that can make your beauty routine more hygienic.
- The study examined 467 used cosmetics and found bacterial contamination across 79% to 90% of the product categories tested.
- Beauty sponges carried the highest microbial loads, and most of those tested had never been cleaned.
- Clean hands, fully dried applicators and sensible replacement habits can reduce avoidable contamination.
What the Makeup Study Actually Found
Researchers Amreen Bashir and Peter Lambert examined used lipsticks, lip glosses, eyeliners, mascaras and beauty blenders donated by consumers. Depending on the product category, approximately 79% to 90% contained bacteria. Researchers identified organisms including Staphylococcus aureus, Escherichia coli and Citrobacter freundii, while fungi and members of the Enterobacteriaceae family appeared across all five categories.
That is concerning, but the distinction matters: these were used personal products, not unopened makeup taken from shop shelves. The study demonstrated contamination and a potential health risk; it did not show that 90% of makeup users develop infections.
Why Makeup Sponges Stood Out
Beauty blenders contained an average bacterial load above one million colony-forming units per millilitre—far higher than the other products tested. Researchers also found that 93% of the sponges had never been cleaned, while 64% had been dropped on the floor and then used again.
The design of a makeup sponge helps explain the problem. It repeatedly touches hands, skin and liquid products, and it is often put away while still damp. Moisture and poor drying conditions can encourage microorganisms to persist and multiply.
Worth Knowing: Cleaning a sponge is only half the job. It also needs to dry completely in a clean, ventilated place rather than being sealed inside a damp makeup bag.
Does Contaminated Makeup Automatically Make You Ill?
No. Finding microorganisms on a product does not prove that it will cause an infection. Risk depends on the organism, the amount present, where the product is applied and the health of the person using it.
The eye area deserves particular care because mascara and eyeliner are repeatedly used close to sensitive tissue. The FDA advises stopping the use of eye cosmetics during an infection and discarding products that were being used when the infection developed.
Anyone who develops persistent redness, swelling, pain, discharge or changes in vision should stop using the suspected product and seek appropriate medical advice.
A More Hygienic Makeup Routine
Start by washing your hands before applying makeup, especially when using products that require dipping a finger into a pot. Keep lids and containers clean and close them securely after use.
Wash reusable brushes and sponges according to the manufacturer’s instructions, rinse them thoroughly and let them dry completely. Do not return a damp applicator to a closed container.
Never share eye or lip products. The FDA also cautions against adding water or saliva to dried mascara because this can introduce microorganisms and dilute the preservatives intended to control their growth.
Store makeup away from excessive heat and moisture. A steamy bathroom may be convenient, but a cool, dry drawer or cupboard is generally a better home for products and applicators.
Know When It Is Time to Let Go
Cosmetics do not remain stable indefinitely. Preservatives can lose effectiveness over time, while repeated contact with fingers, skin and applicators introduces new microorganisms. Changes in smell, colour, consistency or separation are good reasons to discard a product, even when it has not reached a printed date.
Check the package for an expiry date or period-after-opening symbol where one is provided, and follow the manufacturer’s guidance. Writing the opening date on mascara can be especially helpful. The FDA notes that manufacturers commonly recommend replacing mascara approximately two to four months after purchase.
Avoid communal testers unless a fresh disposable applicator is provided, and never apply a shared tester directly to your eyes or lips.
The study is not a reason to panic or replace an entire makeup bag overnight. It is a reminder that products touching the eyes, lips and skin need the same basic care as any other frequently used personal item: clean hands, clean applicators, proper drying and knowing when something has been kept too long.
