If you have ever noticed funky colors or textures in old bottles of nail polish, you may have wondered what that gunk is and whether it could harm you. Rest assured – that harmless discoloration and clumping is likely caused by fungal growth in the polish.
If you’re short on time, here’s a quick answer to your question: Fungus can survive and multiply in nail polish for 1-2 years if the bottle remains sealed. Once opened and exposed to oxygen, fungal growth will slow down but can persist for several months.
Proper storage and tossing polishes at first sign of fungus are key to avoiding potential nail infections down the line.
In this comprehensive guide, we’ll cover everything you need to know about fungal contamination of nail lacquers. You’ll learn what types of fungi grow in polish, how long they can survive, if they pose any risks, and most importantly – how to prevent fungus from taking up residence in your precious polishes in the first place.
What Types of Fungi Grow in Nail Polish?
When nail polish is left sitting for extended periods, it can become a breeding ground for fungal growth. There are a few main types of fungi that may colonize old or unused nail polish:
Airborne Household Molds
Aspergillus, Penicillium, and Cladosporium are extremely common molds that float through the air and can land on surfaces like nail polish. These opportunistic fungi thrive on the ingredients in nail polish such as plasticizers, pearlescent pigments, and acrylic polymers.
Studies show that over 50% of sampled households contain Aspergillus mold, which produces spores that survive for prolonged periods. If nail polish bottles are left open or lids do not seal properly, airborne mold spores can enter and being colonizing the nail lacquer.
Yeasts like Candida
Candida albicans and other yeasts are present on human skin and nails. If someone with a yeast infection on their hands tries on nail polish at a salon or uses a tester, these fungi can be transferred to the polish.
Yeast require nutrients to proliferate, which they can find in the nail lacquer ingredients. One study discovered that over 30% of women have Candida yeast present in their nail beds. If these infected individuals share nail polish, the passage of yeast cells is highly likely.
Dermatophytes that Cause Nail Infections
Dermatophytes like Trichophyton rubrum are filamentous fungi that infect hair, skin, and nails. Studies estimate up to 13% of the population suffers from onychomycosis (nail fungus). Dermatophytes feed on keratin proteins in the nail bed but can also utilize organic compounds found in nail products.
If an infected person shares tools like nail files, clippers, and polish, the transmission rate of the nail fungus can be 20% or higher. Dermatophyte spores can survive for months in matrices like nail polish lacquer before infecting another host.
|50% of households
|30% of women
|Infected nail contact
|13% of population
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Ideal Conditions for Fungal Growth in Polish
Nail polish creates an airtight seal over the nail, trapping moisture against the nail plate and cuticle. This warm, moist environment is ideal for fungal growth. Fungi thrive in dark, damp places with little air circulation.
Polish bottles are the perfect breeding ground once contaminated with fungus spores. Using old or shared polishes increases risk of fungal infection.
Lack of Preservatives
Most nail polishes lack effective preservative ingredients to prevent microbial contamination and growth. A 2014 study found that 89% of tested polishes supported fungal growth for up to 4 weeks. Only 2 brands contained optimal preservatives.
Without proper preservation, fungi introduced through use or manufacturing can proliferate in the bottle.
Infrequent Use Allows Biofilm Formation
Fungi can form protective biofilms in neglected polishes. The longer polish sits between uses, the more time fungi have to establish colonization. An unused or backup bottle provides the perfect stable environment.
One study found that polishes used biweekly had minimal fungal growth compared to abandoned polishes. Regular polish replacement limits contamination risks.
How Long Can Fungus Survive in a Sealed Bottle?
Up to 2 years in ideal environment
Studies have shown that fungal spores can survive for extended periods of time in nail polish bottles, given the right conditions. In an environment with adequate moisture and nutrients, certain species of fungus like Aspergillus and Fusarium can potentially live for up to 2 years sealed inside a bottle. The polish itself provides a source of carbon for the fungus to feed on.
An unopened bottle also maintains high humidity and limits airflow, allowing the fungus to thrive unchecked by competition from other microbes.
Slowed by low oxygen levels
However, nail fungus growth inside sealed bottles is slowed by the low oxygen environment over time. Aerobic fungi require oxygen for optimal development, so the closed system limits their access. While the fungus may survive, its spores will propagate at a reduced rate without fresh external airflow.
Using polish from an unopened bottle with signs of fungus may show reduced infection risk compared to polish from an opened bottle. But fungal spores can still transfer in low oxygen conditions, so caution is advised.
Preservatives limit but don’t prevent growth
Modern nail polishes contain preservatives like formaldehyde that help limit microbial growth, but they do not fully prevent fungus from developing – especially over longer periods. The fungus can adapt to tolerate certain levels of preservatives.
And factors like temperature fluctuations can degrade chemical preservatives over time. So while preservatives impede growth, they cannot guarantee a fungus-free environment in the bottle indefinitely. Proper nail polish storage and careful inspection for signs of contamination are still essential.
Does Fungus in Polish Pose Health Risks?
Low risk of infection in healthy individuals
For most people with healthy nails and immune systems, the risk of fungal infection from contaminated nail polish is relatively low. As the name suggests, nail fungus (also called onychomycosis) is a fungal infection occurring in the nail bed that can cause thickening, discoloration, and crumbling of the nails if left untreated.
Healthy individuals can typically fight off small fungal exposures before infection sets in.
However, some basic precautions should still be taken even for healthy nails:
- Avoid sharing polish or nail tools with others
- Discard old polish that smells odd or has changed consistency
- Use a base coat under polish to create a protective barrier
Following these tips reduces the chance of fungal spores penetrating into the nail bed and decreases nail polish fungus risks significantly.
Higher risk if using on damaged nails
Individuals with preexisting nail damage or disorders face greater vulnerability to nail fungus from contaminated polish. Cracks, hangnails, split nails, and chemical damage from acrylics or artificial tips can all provide an entry point for opportunistic fungal invaders.
Some nail conditions associated with higher fungus infection rates when using old polish include:
Those with compromised nails should take extra care by:
- Carefully inspecting polish before use
- Swabbing nails with disinfectants like isopropyl alcohol before polishing
- Seeing a dermatologist at first signs of infection
Taking these protective steps reduces odds of pesky nail fungus taking hold.
Allergic reactions possible in sensitive individuals
Some ingredients in nail polish can occasionally trigger allergic contact dermatitis (ACD) in sensitive persons. Common allergens include formaldehyde resin, tosylamide, and chemical preservatives.
Reactions tend to manifest as:
- Itchy, red, cracked skin around the nails
- Burning sensation in the nail beds
- Peeling at the tips of the fingers
Those with known skin sensitivities should apply polish sparingly and spot test products before full use. Immediate medical help should be sought for severe reactions like oozing blisters or losing a nail.
By carefully vetting ingredients and limiting use if needed, those prone to ACD can still safely enjoy an occasional manicure.
How to Prevent and Get Rid of Fungal Contamination
Proper storage to limit moisture
Nail polish can easily become contaminated with fungus if it’s not stored properly. Fungus thrives in dark, warm, moist environments. To prevent fungus growth, store nail polishes in a cool, dry place out of the bathroom.
Keep bottles tightly closed and standing up straight to prevent leakage and moisture buildup. Consider storing polishes in an airtight container with desiccant packs to absorb excess humidity.
Avoid sharing polishes
Sharing nail polish with others, whether friends or at a salon/spa, is one of the fastest ways to spread fungus. Each time a contaminated brush is dipped back into the bottle, fungus gets transferred. Never share polishes – buy your own individual colors instead.
At salons, only use polishes that come in small, single-use vials.
Toss gunky bottles ASAP
If you notice any fungal contamination in a nail polish – visible discoloration, clumping, or strange odors – throw it away immediately. Don’t try to salvage gunky polishes by adding thinner or shaking up chunks. Once fungus gets established, it’s extremely difficult to fully eliminate.
It’s better to play it safe and start fresh with a new bottle.
Use antifungal base coats
Adding an antifungal base coat under your nail polish can help prevent and treat fungal overgrowth. Many base coats contain tea tree oil, aloe vera, and other natural antifungal agents. Using one regularly underneath your polish layers will help keep contamination at bay.
Look for base coats specifically marketed as having antifungal properties. Reapply every time you redo your manicure.
Hopefully this guide has helped shed light on the fungi that can grow in old nail polish. While rather unappealing, these organisms are relatively harmless to use for most people. With proper polish hygiene and storage, you can keep your lacquers looking and smelling fresh for longer.
The most important takeaway is to trust your senses. If you notice any odd colors, textures or scents in a polish, it’s best to discard it right away. And be sure to always start your manicures with clean, healthy nails to prevent any possible infections down the line.
With vigilance and care, you can enjoy flawless fingers and toes – and keep fungi out of your nail game for good!