A close-up shot of a UV light device positioned over a hand, showcasing the treatment process of nail fungus.

How Long Does It Take For Uv Light To Kill Nail Fungus?

Nail fungus, also known as onychomycosis, is an embarrassing and frustrating condition that can be tricky to treat. If you’re looking for a fast, effective way to kill the fungus and restore your nails, using UV light is an option worth considering.

If you’re short on time, here’s a quick answer to your question: It can take 3-9 months of consistent application of UV light for it to fully kill nail fungus. The exact time varies based on the severity of the infection.

In this comprehensive guide, we’ll dive into everything you need to know about using UV light as a treatment for nail fungus, including how it works, what factors impact the required treatment duration, safety precautions, at-home vs professional treatments, and more.

What Causes Nail Fungus and Why is it Hard to Treat?

Overview of onychomycosis

Onychomycosis, also known as nail fungus, is a common fungal infection of the fingernails and toenails. It is caused by various species of fungi, such as dermatophytes, nondermatophyte molds, and yeasts.

Nail fungus typically begins as a white or yellow spot under the tip of the nail. As it progresses, the infected nail will become thickened, discolored, and brittle. It may separate from the nail bed and crumble.

In advanced cases, the infection causes the nail to thicken and crumble so much that it becomes painful or impossible to trim.

According to the Centers for Disease Control and Prevention (CDC), around 2-13% of the general population suffers from nail fungus. It is more common in older adults, affecting up to 30% of people over 60 years old.

Common causes of fungal nail infections

There are several factors that can increase the risk of developing nail fungus:

  • Wearing shoes that cause excessive sweating or don’t allow proper ventilation
  • Walking barefoot in damp communal areas like swimming pools, gyms, and showers
  • Having a minor skin or nail injury
  • Having a weakened immune system
  • Having other skin conditions like athlete’s foot or psoriasis
  • Smoking

The fungi thrive in warm, moist environments. Tight-fitting shoes and socks create favorable conditions for infection. Going barefoot in public areas also exposes feet to fungal spores. People with diabetes, circulation problems, and weakened immune systems are at higher risk.

Why the fungus is difficult to eradicate

Treating nail fungus can be challenging for several reasons:

  • Nails grow very slowly. It takes 6 months for fingernails and 12-18 months for toenails to regrow completely. This means it takes a long time to clear the infection.
  • The fungus infects the nail bed below the nail plate. Topical treatments cannot penetrate the nail to reach the fungal infection.
  • Oral antifungal medications can cause side effects like nausea, rash, elevated liver enzymes.
  • Fungus may persist if the factors and conditions that caused the infection are not removed.

Furthermore, the thickened nail can become a reservoir for fungus and bacterial infections. Topical antifungal treatments have difficulty penetrating the dense, hard nail plate. Oral antifungal pills may need to be taken for 12 weeks or longer to eradicate the stubborn fungi at the nail bed.

Treating nail fungus requires patience and perseverance. Removing the diseased part of the nail, debridement, and prescription antifungal pills are often needed. Preventative measures like avoiding tight shoes, keeping feet clean and dry, and not sharing nail clippers reduce the risk of recurrence.

How Does UV Light Kill Nail Fungus?

UV light penetrates the nail

UV light is able to penetrate through the hard keratin layers of an infected nail. The light waves can reach deep down into the nail bed and nail plate where the fungus resides.

It damages the DNA of fungus cells

Once the UV light penetrates the nail, it targets the DNA and cell walls of the fungus. Fungi cells contain thymine, which absorbs UV radiation. The UV exposure causes thymine dimers to form within the cells and disrupts the DNA structure and replication process.

This disruption prevents further growth

With the DNA damaged and cell walls compromised, the fungus struggles to reproduce and spread. The germination of existing spores is halted. Mycelium, the vegetative parts, are no longer able to grow either. This essentially stops the infection in its tracks.

Effective fungus-killing wavelengths fall into the ranges of 240-280 nm (UVC) and 315-400 nm (UVA). However, only nail lamps with UVC light are able to produce enough energy to achieve germicidal effects deep in the nail.

According to American Family Physician, UV phototherapy treatments should be administered by a clinician twice per week, with each session lasting 10 to 15 minutes. After just 1 to 2 months, the new clear nail growth is typically evident.

It can take 9-12 months to completely replace an infected nail.

UV therapy has a reported 60-80% success rate when treating onychomycosis. The numbers vary slightly across studies due to differences in evaluation timeframes. While home treatments appear somewhat effective too, professional phototherapy remains the gold standard.

Factors That Impact Treatment Duration

Severity of infection

The more severe the nail fungus infection, the longer it will take to fully treat. Mild infections limited to the tips of the nails may take only a few weeks of consistent UV light exposure to resolve.

However, infections that have spread to the nail beds and surrounding skin or affect the entire nail plate can take 3-9 months of treatments to eliminate the fungus.

Number/type of nails infected

The more nails that are infected, the longer the overall treatment time. If only one or two fingernails are affected, they can often be cleared up in 4-8 weeks. However, if all ten fingernails and toenails are infected, it may take 6-12 months to fully treat all of them.

Toenails tend to be harder to treat than fingernails due to slower growth, so the presence of toe infections also lengthens the treatment duration.

Consistency of UV exposure

For the fastest results, UV light treatments should be done consistently, ideally every day. Frequent exposures are important because the UV light can only treat the parts of the nail newly exposed as the nail grows out.

Skipping treatments allows the fungus-infected parts of the nail to grow longer, necessitating more treatments to eliminate it. Doing treatments at least 5 days a week is recommended for optimal clearance within 3-6 months.

Health of nails and skin

Damaged, brittle nails or surrounding skin take longer to heal from fungal infections. Underlying conditions like psoriasis or eczema can also slow treatment progress. Keeping nails trimmed to decrease thickness and applying moisturizer to soften cuticles and skin can help improve UV light effectiveness.

Taking oral antifungal medication concurrently speeds up healing by attacking infection internally while UV treats externally.

Is UV Treatment Safe? Potential Risks

Can UV damage healthy skin and nails?

UV light has the potential to damage healthy skin and nails if not used properly. The high-energy UV rays used to treat nail fungus can burn the surrounding skin if exposed for too long. This is why it’s crucial to carefully follow your doctor’s instructions on exposure times.

Most dermatologists recommend starting with very short exposure times like 30 seconds and gradually increasing over multiple treatments. This allows the skin to build up tolerance and avoids burns. Properly applied, most people can undergo phototherapy for nail fungus without long-term damage to healthy tissue.

Risk of burns

As mentioned above, UV therapy does carry a risk of burns if not administered properly. Burns can occur after just a single overly long exposure. They usually appear within 24 hours as redness and swelling of the affected area. In severe cases, blistering may occur.

To avoid burns, keep the UV wand a proper distance from the skin, limit initial exposure times, and increase duration gradually per your doctor’s guidance. Also avoid sun exposure on treatment days to reduce any additive risk.

Tell your doctor immediately if you do experience a burn so they can adjust the treatment protocol.

Importance of proper eye protection

Since UV light can damage unprotected eyes, proper eye safety measures are vital during treatment. Your doctor will provide special goggles designed to block 100% of UV rays. These must be worn not only by the patient but anyone else in the room during a treatment session.

Some doctors also recommend covering the eyes with a damp washcloth as an added precaution. Avoid looking directly at the UV lamp when it’s on. Follow all eye protection instructions carefully, and speak up if the goggles provided don’t seem adequately protective. Safeguarding your eyes is essential.

Who should avoid UV treatment?

While often safe when properly administered, certain people are better candidates for oral antifungal medication rather than UV therapy for nail fungus. These include:

  • Those with very fair skin or a history of skin cancer – Increased UV exposure raises skin cancer risk
  • People taking photosensitizing medications – These make the skin more vulnerable to burns
  • Pregnant or breastfeeding women – Effects of radiation exposure on fetus/baby are uncertain
  • Those with eye disorders or previous eye surgery – Increased light sensitivity
  • Children – Long-term effects of UV exposure are unknown

People with claustrophobia may also have difficulty tolerating the protective goggles during treatment. Talk to your doctor about whether UV nail fungus treatment is right for your individual health status and concerns.

At-Home vs Professional UV Nail Fungus Treatment

Overview of at-home devices

At-home UV nail fungus devices provide an accessible and convenient option for treating nail fungus in the comfort of your own home. Many reputable brands like Care Me and Kuru offer handheld wands or tabletop devices with UV-C bulbs that emit wavelengths between 200-280 nm to eliminate fungus.

Using an at-home device typically involves exposing each nail to the UV light for a set period of time, ranging from 2-5 minutes per nail. Treatment needs to be done routinely until the fungal infection clears. On average, it takes 3-6 months to eliminate a mild case completely at home.

Types of in-office UV devices

Podiatrists or dermatologists can perform in-office UV phototherapy using specialized equipment like the Qurelix nail fungus laser or the PinPointe FootLaser. These medical devices utilize targeted UV wavelengths alongside heat and laser technology to penetrate deeper and work faster than at-home treatment.

Common modalities include superficial UV therapy for surface-level infections, or photo-dynamic therapy (PDT) which uses a photosensitizing agent alongside UV exposure to enhance effectiveness in killing fungal spores.

The pros and cons of each option

At-home Professional
  • More affordable (devices under $100)
  • Convenient to perform anytime
  • Takes longer (3-9 months)
  • Higher recurrence risk
  • Fast clearance (1-4 sessions)
  • Podiatrist supervision
  • Higher clearance rates
  • Expensive (costs hundreds per session)
  • When weighing these UV treatment options, consider factors like infection severity, affordability, convenience and your commitment to following treatment protocols. Consulting your podiatrist can help guide your decision.

    Tips for Effective At-Home Treatment

    Get the right device

    When treating nail fungus at home, it’s important to use a device designed specifically for this purpose. LED lamps or UV lamps made for home use are available at many pharmacies and online retailers. Consumer-grade lamps may not provide enough power to fully penetrate the nail and kill the fungus.

    Getting a quality UV or LED device made for treating nail infections can help improve your chances of success.

    Be patient and consistent

    At-home light therapy for nail fungus requires commitment. You’ll need to treat the affected nail(s) as recommended, usually every day or a few times per week, for several months. Nail fungus is very stubborn, so don’t expect overnight results.

    Stay diligent with the treatments and you should begin to see improvement within a couple months. But a complete cure can take 9-12 months or more. Patience and persistence are key.

    Supplement with other treatments

    Using a UV or LED light is often most effective when combined with an oral or topical antifungal medication. Ask your doctor about supplementing the phototherapy with prescription antifungals like terbinafine or itraconazole pills, or topical ointments containing ingredients like efinaconazole or tavaborole.

    This multi-pronged approach provides treatment from the inside and outside simultaneously, offering greater chance for eradicating the fungal infection completely.

    Disinfect devices properly

    It’s very important to clean and disinfect any device used for nail fungus treatment after every use. Otherwise, you risk reinfecting the nail or spreading the fungus to other nails. Rubbing alcohol or an EPA-registered disinfectant should be used to wipe down the entire lamp.

    You’ll also need to fully wash/disinfect removable parts like trays or clips that touch the nail. Proper hygiene habits are essential for getting max benefit from at-home phototherapy.


    While UV treatment requires patience and diligence, it offers an effective way to clear nail fungus without the risks and side effects of oral medications. With a thorough understanding of what to expect and how to use the technology properly, you can get rid of even severe infections and restore the health and appearance of your nails.

    Commit to using your UV device as directed 3-4 times per week, supplement when needed with topical creams or oils, and be diligent with disinfecting. With time, you’ll start seeing clear, fungus-free nails again.

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