Killing fungus depends on where it’s growing: on your body, on household surfaces, or in your nails. Each situation calls for a different approach, but the core principle is the same. Fungal cells rely on a unique membrane component that human cells don’t have, which is why antifungal treatments can target fungi without harming you. Here’s what actually works, how long it takes, and what to skip.
How Antifungals Kill Fungus
Fungal cell membranes contain a substance called ergosterol, which serves the same structural role that cholesterol plays in human cells. Because your cells don’t use ergosterol, antifungal drugs can attack it without damaging your own tissue. Most antifungal medications work by blocking the production of ergosterol, which makes the fungal cell membrane leak until the cell ruptures and dies.
This is the mechanism behind the most common over-the-counter creams and prescription pills. It’s also why antifungals are generally well tolerated compared to, say, antibiotics, which sometimes struggle to distinguish bacterial targets from human ones.
Killing Fungus on Skin
For common skin infections like athlete’s foot, jock itch, and ringworm, topical antifungal creams are the standard fix. Terbinafine cream applied once daily for one to two weeks produces mycological cure rates (meaning the fungus is actually gone, not just visually improved) between 84% and 94%. Clinical cure rates, where symptoms fully resolve, range from 75% to 84%.
The key mistake people make is stopping treatment when the rash looks better. Fungal cells can persist below the skin’s surface even after itching and redness fade. Finish the full one to two weeks regardless of how things look. Clotrimazole and miconazole are widely available alternatives that work through the same ergosterol-disrupting mechanism, though terbinafine tends to require shorter treatment courses.
Keep the area dry between applications. Fungi thrive in moisture, so switching to moisture-wicking fabrics and drying skin thoroughly after showering makes a real difference in whether the infection comes back.
Treating Nail Fungus
Nail fungus is significantly harder to kill than skin fungus because the infection lives beneath the nail plate, where topical creams can’t easily reach. Treatment takes months, not weeks, and the nail has to grow out completely before you’ll see the full result.
Oral antifungal pills taken for three to six months have long been the standard treatment. Laser therapy is a newer option that shows promising results. A meta-analysis of eight clinical trials found that laser treatment produced higher mycological cure rates than oral terbinafine, with roughly three times the odds of clearing the fungus after three to six months of follow-up. Clinical improvement rates were similarly higher, and laser therapy came with fewer side effects.
That said, nail fungus has a reputation for relapsing regardless of treatment method. Even after successful clearance, reinfection is common, particularly if you frequently expose your feet to warm, damp environments like gym showers or shared pools. Keeping nails trimmed short and wearing breathable footwear helps reduce the odds of recurrence.
Killing Mold on Household Surfaces
For mold growing on walls, tile, or other surfaces in your home, the approach depends on whether the surface is porous or non-porous.
On non-porous surfaces like tile, glass, and sealed countertops, household bleach diluted to standard concentration (roughly 5,250 parts per million of sodium hypochlorite, which is what you get from mixing about half a cup of regular bleach per gallon of water) kills over 99% of mold with a 10-minute contact time. Spray it on, let it sit for a full 10 minutes while the surface stays wet, then wipe clean.
On porous surfaces like drywall, bleach still works but may require repeated applications. Research from the University of Arizona found that household bleach achieved significant mold reduction on drywall, with complete removal possible after treating the same area more than once. The issue is that mold hyphae (root-like threads) can penetrate deep into porous materials, so a single wipe-down won’t always reach everything.
Commercial mold-killing products use similar active ingredients. EPA-registered formulations typically require that the surface remain wet for about 10 minutes to be effective against common mold species.
Vinegar and Tea Tree Oil
White vinegar, with its 5% to 8% acetic acid content, does kill some types of mold but not all. A 2015 study found that vinegar at 4% to 4.2% acetic acid was effective against Penicillium chrysogenum (a common green household mold) but failed against Aspergillus fumigatus, a more resilient species. If you use vinegar, spray it undiluted and let it sit for at least an hour before wiping.
Tea tree oil has genuine antifungal properties. Lab research has demonstrated that it inhibits the growth of Candida albicans (the yeast behind most thrush and yeast infections) at very low concentrations. However, killing established fungal colonies requires concentrations roughly 100 times higher than what’s needed to simply stop growth. In practice, tea tree oil works better as a preventive measure or mild treatment than as a way to eliminate a serious fungal problem. A few drops mixed into a spray bottle of water can help maintain surfaces that have already been cleaned, but it won’t replace bleach or a dedicated antifungal product for active infestations.
Using Heat to Kill Fungus
Heat is one of the most reliable ways to kill fungal spores, and the temperature thresholds are well established. Common household molds like Aspergillus niger and Penicillium species die at 60°C (140°F) after 60 minutes of exposure and cannot survive 70°C (158°F) for even 10 minutes.
More heat-resistant species require higher temperatures. Aspergillus fumigatus, a particularly tough mold, survives 80°C (176°F) for up to an hour but dies within 10 minutes at 90°C (194°F). The most resistant soil fungi can survive 90°C for extended periods, but these rarely cause indoor problems.
For practical purposes, this means washing contaminated fabrics, towels, or bedding on a hot cycle (most washing machines reach 60°C on the “hot” setting) will kill the majority of common fungi. Steam cleaners, which typically operate above 100°C, are effective for carpets and upholstery. If you’re dealing with athlete’s foot that keeps coming back, washing socks and shoes on hot and fully drying them is just as important as applying antifungal cream to your skin.
Preventing Fungal Growth Indoors
Fungi need moisture to germinate and grow. The EPA recommends keeping indoor relative humidity between 30% and 50%, and no higher than 60%. Above 60%, condensation forms on surfaces and creates the conditions mold needs to colonize walls, ceilings, and fabrics.
A simple hygrometer (available for under $15 at most hardware stores) lets you monitor humidity in problem areas like bathrooms, basements, and laundry rooms. If you’re consistently above 60%, a dehumidifier is the single most effective prevention tool. Fixing leaks promptly matters too: mold can begin colonizing a damp surface within 24 to 48 hours. Ventilating bathrooms during and after showers, using exhaust fans in kitchens, and ensuring clothes dryers vent outdoors all help keep humidity in the safe range.
When Fungus Resists Treatment
Some fungal infections don’t respond to standard treatments. Candida auris, an emerging fungal pathogen, has become a serious concern because of its resistance to multiple drug classes. In the United States, about 90% of C. auris isolates resist fluconazole (the most commonly prescribed antifungal pill), roughly 30% resist amphotericin B, and some isolates resist all three major classes of antifungal drugs. Cases of complete pan-resistance have been reported internationally.
C. auris is primarily a hospital-acquired infection and not something most people will encounter at home. But its existence illustrates why persistent or worsening fungal infections deserve professional evaluation. If an over-the-counter antifungal cream hasn’t improved a skin infection after two full weeks of consistent use, or if a nail infection keeps returning despite treatment, the specific fungal species involved may need to be identified so the right medication can be matched to it.