Fungus is killed by heat, ultraviolet light, chemical disinfectants, and antifungal medications, but the right approach depends entirely on where the fungus is: on your skin, in your home, on your clothes, or on a surface. Each method works by attacking a different part of the fungal cell, either dissolving its protective membrane, punching holes in its cell wall, or destroying its DNA.
How Antifungal Medications Work
Fungi have a unique weakness that antifungal drugs exploit: their cell membranes are built with a fat molecule called ergosterol instead of the cholesterol found in human cells. This difference is what allows medications to target fungi without destroying your own tissue. The most commonly prescribed antifungals, including fluconazole and itraconazole, work by blocking the enzyme that produces ergosterol. Without it, the fungal membrane becomes leaky and structurally unstable, and the organism dies.
A second class of antifungals takes a more direct approach. Rather than starving the membrane of ergosterol, drugs like amphotericin B bind directly to the ergosterol already present and punch physical holes through the membrane. Vital contents leak out and the cell collapses. This is one of the most powerful antifungal strategies available, though it’s typically reserved for serious systemic infections because it can affect human cells too.
A third class targets the fungal cell wall itself, which is a rigid outer shell that human cells don’t have. These drugs block production of a structural sugar called glucan that holds the wall together. Without glucan, the wall weakens and the fungus can’t maintain its shape or survive. This is the mechanism behind echinocandin drugs used in hospitals for severe Candida and Aspergillus infections.
Topical Treatments for Skin Fungus
For common infections like athlete’s foot, ringworm, and jock itch, over-the-counter creams containing terbinafine or clotrimazole are the standard first step. Terbinafine is particularly effective against the dermatophyte fungi that cause these skin infections. In clinical trials, a single application of a 1% terbinafine solution cleared the fungal infection in 72% of patients with athlete’s foot by week six, compared to 21% with placebo. Among those who were successfully treated, about 12.5% had the infection return within three months.
The typical over-the-counter regimen involves applying terbinafine cream once or twice daily for one to two weeks. Consistency matters more than quantity. Fungal skin infections often look better before the organism is fully eliminated, which is why stopping treatment early is one of the most common reasons for recurrence. If a topical treatment hasn’t worked after two to four weeks, oral antifungals prescribed by a doctor are the next option.
Heat: The Simplest Fungal Killer
Most yeasts and molds are destroyed at temperatures between 140°F and 160°F (60°C to 71°C), according to USDA research. That’s well below boiling, which means sustained heat from cooking, pasteurization, or even a hot washing machine cycle is enough to kill the vast majority of fungal organisms. A few heat-resistant species, like the mold Byssochlamys fulva (which spoils canned fruit), require a full minute at boiling temperature to die, but these are exceptions.
For everyday purposes, the most practical application of heat is laundry. Dermatophyte fungi, the type responsible for athlete’s foot and ringworm, survive a 40°C (104°F) wash cycle just fine. Every contaminated fabric sample washed at that temperature still grew fungus within days. But washing at 60°C (140°F) eliminated dermatophyte spores completely, with or without detergent. The temperature alone did the work. If you’re dealing with a fungal skin infection, washing socks, towels, and bedding at 60°C or higher is one of the most effective things you can do to prevent reinfection.
UV Light and Sunlight
Ultraviolet-C light, the short-wavelength UV used in germicidal lamps, destroys fungal DNA and prevents reproduction. The dose required varies dramatically by species. Candida albicans, the yeast behind most thrush and vaginal yeast infections, needs a median UV-C dose of about 9 mJ/cm² in liquid to achieve a 90% kill. The drug-resistant species Candida auris requires roughly 14.5 mJ/cm². Trichophyton rubrum, which causes athlete’s foot and nail fungus, needs about 27.6 mJ/cm² to neutralize its spores. Aspergillus niger, a common black mold, is one of the toughest, with a median spore dose around 107.5 mJ/cm².
Consumer UV-C devices exist for sanitizing shoes, phone cases, and small items, but effectiveness depends heavily on dose, distance, and exposure time. Surfaces in shadow or crevices won’t receive enough light. Natural sunlight contains some UV, but at far lower germicidal intensity than dedicated UV-C lamps. Drying items in direct sunlight can help reduce fungal growth, but it’s not a reliable substitute for heat or chemical treatment.
Chemical Disinfectants and Household Cleaners
Several common chemicals kill fungus on hard surfaces. Bleach (sodium hypochlorite) at standard household concentrations is effective against most molds and yeasts, though it requires adequate contact time, meaning the surface needs to stay visibly wet with the solution for several minutes rather than being wiped off immediately. Hydrogen peroxide at 3% concentration also works against many fungal species.
The critical detail with any disinfectant is contact time. Fungal spores are significantly harder to kill than bacteria or most viruses, so the surface must remain wet with the product longer than you might expect. Check the product label for the contact time listed specifically for fungal claims, as it’s often longer than the time listed for bacteria. Scrubbing porous surfaces like grout or wood before applying disinfectant helps because fungal hyphae can grow into tiny cracks where liquid disinfectants can’t penetrate.
Copper and Other Metal-Based Fungicides
Copper has been used as a fungicide for over a century, and it remains one of the few fungicides approved for organic farming. Copper ions kill fungi by denaturing their proteins and enzymes on contact. This makes copper effective as a preventive surface treatment: it works before fungal spores have a chance to germinate and penetrate plant tissue. Once an infection has taken hold inside a plant, copper sprays are far less useful because the ions can’t reach the fungus growing within the cells.
Copper-infused products like socks, shoe insoles, and pillowcases are marketed for their antifungal properties, and copper surfaces do show genuine antimicrobial activity. However, the concentration and duration of contact matter. A copper-infused sock won’t replace antifungal medication for an active infection, but it may help reduce fungal load between treatments.
Why Some Fungi Are Harder to Kill
Fungal spores are the survival form of the organism, built to endure harsh conditions. They’re consistently harder to kill than actively growing fungal cells, regardless of the method you use. This is why mold remediation in homes, clearing a toenail infection, or decontaminating a surface often requires repeated or prolonged treatment rather than a single attempt.
Drug resistance is also a growing problem. Candida auris, a species that emerged in the last decade, resists multiple antifungal drug classes and has caused hospital outbreaks worldwide. Among more common species, fluconazole resistance exceeds 20% in some Candida strains circulating in southern Europe, South America, and South Africa. Candida albicans, the most familiar yeast pathogen, still has resistance rates below 1%, but less common species are catching up. Some fungi also produce biofilms, slimy protective layers that shield them from both your immune system and antifungal drugs, making infections on medical devices and in wound sites particularly stubborn.
The practical takeaway: matching the right killing method to the right situation matters. Heat and UV work on surfaces and fabrics. Chemical disinfectants work on hard, non-porous materials. Antifungal medications, whether topical or oral, are what you need for infections on or inside the body. And for any method, giving it enough time and intensity to work is the difference between suppressing fungal growth and actually eliminating it.