Do UV Sanitizers Work?

Claire Gillespie is an experienced health and wellness writer. Her work appears across several publications including SELF, Women’s Health, Health, Vice, Headspace, and The Washington Post.

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Ultraviolet (UV) sanitizers use UV rays to sterilize surfaces. UV sanitizers have been shown to work, with some devices eliminating nearly 99.99% of bacteria, fungi, and viruses that cause disease.

Some UV sanitizers are hospital-grade, tall fixtures with bulbs that emit UV rays for a set amount of time. They are also available as smaller, portable devices to cleanse personal items like phones, shoes, and toothbrushes.

UV sanitation is a disinfection method that eliminates bacteria, fungi, and viruses without harsh chemicals or heat. UV is a type of electromagnetic radiation that produces light not visible to the naked eye. The most common source is sunlight.

There are three types of UV light, which produce different wavelengths of light, including:

UVA and UVB rays may cause damage to your skin and increase the risk of skin cancer if you are outdoors too long without protection, such as sunscreen. The atmosphere absorbs UVC rays before they reach the Earth's surface.

Manufacturers use UVC in UV sanitizers, available in artificial lamps and lasers.

UVC rays with a wavelength of at least 254 nanometers eliminate 99.99% of microbes that cause disease.

UV sanitizers use UVC rays to damage a germ's genetic material (i.e., DNA and RNA) so it cannot multiply. At shorter wavelengths than 254 nanometers, UVC rays may damage the proteins on germs, so they cannot attach to your cells.

"[UV sanitizers] speed up cross-linking of this genetic material, which reduces the ability of the genetic material to participate in healthy replication," Karen Dobos, PhD, scientific director for the Regional Biocontainment Laboratory at Colorado State University, told Health.

SARS-CoV-2, the virus that causes COVID-19, is vulnerable to UVC rays emitted by UV sanitizers. UV sanitizers can inactivate SARS-CoV-2 within nine minutes of exposure to UVC rays.

The Environmental Protection Agency (EPA) does not list UV lights on List N, a list of disinfectant products that work against SARS-CoV-2. More research is needed to fully understand the effects of UVC rays on the virus.

In addition to hospital-grade UV sanitizers, manufacturers have created portable devices that disinfect small surfaces, such as phones, shoes, and toothbrushes.

Different types of UV sanitizers are available—from wands to zip-up pouches—to sanitize various items. A wand might target household items like doorknobs, but a pouch might be more fit for small items like a phone.

Do not expose your eyes and skin to the UVC rays emitted by UV sanitizers, William Schreiber, PhD, chair of the department of chemistry and physics at Monmouth University, told Health.

LightStrike, a far-UVC light used in hospitals, has been shown to eliminate 99.99% of SARS-CoV-2 within 1 meter of the device within two minutes. Far-UVC lights complement, rather than replace, other disinfectant methods.

Far-UVC lights do not deeply penetrate the eyes or skin, which lowers the risk of cataracts (cloudy lens of the eye), skin cancer, and other injuries.

UV sanitizers are available as portable devices that disinfect phones, which may carry infectious germs.

PhoneSoap is a UV sanitizer that envelops your phone and exposes it to 16 UVC bulbs. One 30-second cleaning cycle can lower the number of germs by 90.5%. Two cleaning cycles can eliminate nearly 99.9% of germs.

Certain UV sanitizers help disinfect shoes, which lowers the risk of fungal infections. UV sanitizers that use UVC rays at a wavelength of 200-300 nanometers effectively get rid of fungus on the soles of shoes.

Some UV sanitizers sanitize toothbrushes, which experts advise regularly disinfecting or replacing to decrease the risk of illness. They can effectively reduce germs on toothbrushes after brushing.

Hospital-grade and personal UV sanitizer may effectively and quickly disinfect surfaces. Some factors may affect their effectiveness.

Using a personal UV sanitizer may do more harm than good in the long run. Antimicrobial resistance happens when bacteria, fungi, and viruses adapt and change to become resistant to certain environments.

"[UV sanitizers] can be dangerous, especially with repeated exposure," said Dobos. Many microbes will naturally have some adaptation or resistance to UV rays since they replicate and mutate faster than other organisms.

"This population of microbes will get greater and greater within your home, especially with repeated exposure," said Dobos.

Consumer products are likely less effective against microbes than industrial UV sanitizers since they have lower energy.

"The energy emitted from these bulbs has to be very low to be sold for personal use, which isn't the case for industrial applications," said Dobos.

Some hospitals rely on UV rays to help sterilize surfaces. One study found that UVC light used in hospitals cut transmission of four major superbugs by 30%. UV sanitizers for personal use may be less powerful.

The UVC rays emitted by UV sanitizer may also lose their potency over time.

"As it decays, [UV sanitizer] becomes even less effective for its target, and I don't know how a person could tell how these bulbs are decaying," said Dobos. "I'm sure there's a 'replace by' date, but most of us only replace a light bulb when it goes completely out. This is well beyond the effective time for a UV source."

If used unsafely, some UV sanitizers may increase the risk of conditions, such as:

Certain UV wands may cause skin, eyes, or both injuries after a few seconds of use. Report any problems with a UV sanitizer to the manufacturer and the Food and Drug Administration (FDA).

Do not use products listed on the FDA's list of unsafe UV wands. Testing has found that these wands emit dangerous levels of UVC radiation, which increases eye and skin injuries.

Take extra precautions to avoid injuring yourself or others using UV wands. Only use UV wands with safety instructions. Ensure you follow all safety instructions, especially to protect your eyes and skin.

Other disinfecting methods help maintain clean, safe surfaces. Use a household cleaner that contains soap or detergent to decrease the risk of infection from surfaces in your home. Healthy air ventilation also helps.

UV sanitizers help disinfect surfaces by inactivating infectious bacteria, fungi, and viruses. Portable devices—such as those that clean phones, shoes, and toothbrushes—may be less effective than hospital-grade UV sanitizers.

There are other ways to disinfect surfaces in your home. Cleaning with simple soap or detergent, having good air ventilation, and routinely disinfecting help disinfect your home.

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