What Is a Fungal Nail Infection?
A fungal nail infection — onychomycosis, if you want the clinical term — is exactly what it sounds like. A fungus gets under or into the nail and takes up residence. Left alone, it spreads slowly through the nail plate, causing it to thicken, discolour, and sometimes crumble at the edges.
It’s more common than most people realise, affecting around 10% of adults in the UK. It’s also more stubborn than most people expect — which is why so many tubes of treatment sit half-finished at the back of bathroom cabinets up and down the country.
I know this from personal experience. About fifteen years ago I stubbed my big toe badly on a pile of my kids’ toys in the dark — one of those moments where you stand very still afterwards and breathe through your nose until the urge to say something unrepeatable passes. The nail was damaged, grew back slowly, and somewhere during that regrowth process a fungal infection took hold. What followed was a solid year of treatment, a lot of patience, and a much healthier respect for leaving the hallway light on at night.
The good news: fungal nail infections are very treatable. They just require the right approach and — this part is important — a realistic sense of how long it takes.
What Causes a Fungal Nail Infection?
The same fungi that cause athlete’s foot (dermatophytes, mostly) are responsible for the majority of fungal nail infections. They thrive in warm, moist environments — which is why feet are such a common target.
Common routes in:
- Damaged nails — a stubbed toe, a nail that’s been caught or torn — as I discovered — creates an opening the fungus can exploit
- Communal changing areas — swimming pools, gym showers, sports changing rooms
- Tight or poorly-ventilated footwear — traps heat and moisture, exactly the conditions fungi love
- Athlete’s foot left untreated — the infection can spread from the surrounding skin into the nail itself
- Age — nails become more porous and slower-growing over time, making infection easier to establish and harder to treat
If you’re immunocompromised, diabetic, or have poor circulation, you’re at higher risk — and more reason to treat it promptly rather than waiting to see if it sorts itself out. See our diabetic foot care guide for more on why nail health matters particularly if you have diabetes.
How to Tell If It’s Fungal
The signs are fairly recognisable once you know what you’re looking for:
- Thickening of the nail — it becomes harder to cut
- Discolouration — yellow, white, brown, or greenish tinge
- Crumbling or brittle edges — the nail breaks or flakes rather than cutting cleanly
- Separation from the nail bed — a gap forms underneath
- Mild odour in more advanced cases
One thing worth knowing: not every discoloured or thick nail is fungal. Psoriasis can cause very similar-looking nail changes, as can trauma. If you’re not certain what you’re dealing with, a podiatrist can confirm it quickly — often just from looking at it, or by taking a nail clipping for analysis. Treating the wrong thing for months is a waste of time and money. Find a podiatrist near you
Home Treatment Options
1. Antifungal Nail Lacquers — Start Here
For mild to moderate infections, an antifungal lacquer is the right first step. These work by penetrating the nail plate and delivering antifungal agents directly to the infected tissue. They’re applied like a nail varnish — usually once a week or daily depending on the product — and they genuinely work, with one significant caveat: they work slowly.
We’re talking months, not weeks. Nails grow approximately 1–2mm per month, and the lacquer needs to work through the full thickness of infected nail. For a big toenail, you’re realistically looking at 9–12 months of consistent use before you see a fully clear nail — if the treatment is working from month one.
This is where most people go wrong. They apply it for six weeks, see no visible change, and stop. The treatment was probably working. The nail just hadn’t grown out yet.
My picks:
Curanail (Amorolfine 5% Nail Lacquer)
The one I’d reach for first for a mild to moderate infection. Amorolfine is the active ingredient in most prescription-strength lacquers and Curanail is now available over the counter. Applied once a week, which makes consistency easier to maintain over the long course of treatment. Have a look at the application kit included — the filing and cleaning steps before you apply are actually doing a lot of work, and the kit makes it easier to do them properly.
Excilor Fungal Nail Treatment
A solid alternative that uses a different delivery mechanism — an acetic acid formulation rather than a traditional lacquer. Applied daily, which suits people who find a weekly routine harder to stick to. The pen applicator is worth a look; it makes precise application much more straightforward than older brush-on formats.
Canesten Once Weekly Nail Treatment
Another amorolfine-based option. Competitively priced and widely available. Worth checking current prices at online pharmacies if you’re planning a longer course — the cost of weekly treatment over 9–12 months adds up, and the savings from buying in bulk can be significant.
2. Oral Antifungals — When Lacquers Aren’t Enough
If the infection is severe, affects multiple nails, or a lacquer course hasn’t made progress, oral antifungal medication (terbinafine or itraconazole) is considerably more effective. These work systemically — through the bloodstream — rather than trying to penetrate the nail from the outside.
Oral antifungals require a prescription from your GP. They’re not suitable for everyone — they interact with some medications and aren’t recommended during pregnancy — so a conversation with your doctor is the right route. But for stubborn or extensive infections, they’re substantially more effective than any over-the-counter product.
This isn’t something to seek out before trying a lacquer. But if you’ve done a proper lacquer course and made no progress, it’s worth asking your GP about rather than buying yet another tube of something different.
Online pharmacies:
For those who’d rather not wait for a GP appointment, some regulated online pharmacies can assess and prescribe after an online consultation.
Click Pharmacy
One of the better-organised options for online consultations. Worth having a look at how the consultation process works — it’s quicker and more straightforward than most people expect.
Pharmacy2U
The UK’s largest online pharmacy. Useful if you want to manage a fungal nail consultation alongside other prescriptions in one place.
What a Podiatrist Can Do That You Can’t
If home treatment hasn’t shifted it after a proper course — or if the infection is extensive, painful, or affecting multiple nails — a podiatrist has several options that simply aren’t available over the counter.
I saw enough at the clinic to know that podiatrists deal with stubborn fungal nails regularly, and they have tools and treatments that change the picture completely. A year of ineffective home treatment is often resolved in a few clinic appointments.
Mechanical Debridement
Before any clinical treatment, a podiatrist will file or burr away the thickened, infected nail tissue. This alone makes topical treatments significantly more effective — the lacquer doesn’t have to penetrate half a centimetre of damaged nail plate. It’s painless, quick, and often the step that makes everything else work.
Prescription-Strength Topical Treatment
Podiatrists can apply higher-concentration antifungal agents and, in some cases, provide nail avulsion (removal of the nail) to allow direct treatment of the nail bed. Not as alarming as it sounds — done properly under local anaesthetic it’s a very straightforward procedure.
Laser Treatment
Laser fungal nail treatment is one of the more significant advances in podiatric practice over the last decade. The laser targets the fungal cells specifically without damaging the surrounding tissue, and results — particularly for nails that haven’t responded to other treatments — can be very good. It’s typically 2–4 sessions, and it’s not cheap, but for a nail that’s been resistant to everything else it’s often the answer.
Swift Microwave Therapy
The same Swift technology used for verrucas (see our verruca treatment guide) is now used for fungal nail infections in some clinics. Early results are promising, and it’s worth asking about when researching podiatrists if this is something you’re considering.
If yours has been there a while and OTC treatment hasn’t made a dent, stop buying more of the same and book an appointment instead. Find a podiatrist near you
Stopping It Coming Back
- Treat athlete’s foot promptly — it’s the most common route into the nail. Don’t let it linger.
- Keep nails short and dry — cut straight across rather than curved, and dry thoroughly between toes after washing
- Use antifungal powder or spray in shoes, particularly sports shoes and boots you wear regularly
- Rotate your footwear — give shoes 24 hours to dry out properly between wears
- Wear flip flops or pool shoes in communal changing areas — this one I wish I’d been more consistent about
- Don’t share nail clippers, files, or towels
- Check your footwear — shoes that are too tight or poorly ventilated are a contributing factor. For footwear that gives your feet proper room, see our wide fit shoes guide.
FAQ
How long does fungal nail treatment take?
Longer than most people expect. Nail lacquers need 9–12 months of consistent use for a big toenail to grow out fully clear. Oral antifungals work faster — typically 6–9 months — because they work systemically. Laser treatment produces results more quickly in clinical settings, often across 2–4 sessions. The key thing with any treatment is consistency over the full course, not stopping when you stop seeing visible progress.
Does fungal nail go away on its own?
Occasionally in mild cases, but it’s rare. Fungal nail infections are caused by a living organism that has established itself in the nail tissue — it’s not going to resolve without active treatment in the vast majority of cases. Waiting and hoping generally means a more established infection that’s harder to treat later.
Can I paint over a fungal nail?
With regular nail varnish — no. It seals in the moisture and makes the infection worse. With an antifungal treatment product — yes, that’s exactly what you should be doing, and the treatment products are designed to be applied directly to the nail. Some people use a cosmetic nail varnish over the top once the antifungal has dried, which is generally fine, but worth checking with the product instructions.
Is fungal nail contagious?
Yes, though it requires fairly direct contact — shared towels, nail clippers, or footwear, or walking barefoot in communal areas where an infected person has walked. It can spread between your own nails if left untreated. Family members living in close proximity do have a slightly elevated risk.
When should I see a podiatrist for a fungal nail?
If the infection covers more than half the nail, affects multiple nails, is causing pain, or you’ve completed a full 9–12 month lacquer course without improvement — see a podiatrist. Also see one if you have diabetes, poor circulation, or a compromised immune system rather than self-treating. Find a podiatrist near you
How much does laser fungal nail treatment cost?
Prices vary by clinic and location, but typically £200–£600 for a course of treatment (usually 3–4 sessions). It’s not cheap — but for a nail that’s been resistant to everything else for years, the cost-per-result calculation often looks quite different. A podiatrist can advise whether you’re a good candidate before you commit.
The Bottom Line
Fungal nail infections are common, stubborn, and very treatable — but they require patience and consistency more than anything else. A good antifungal lacquer used properly for the full course will resolve most mild to moderate infections. For anything more established, oral antifungals or clinical treatment will do what months of over-the-counter products can’t.
The mistake most people make is stopping too soon or switching products before giving any of them a proper chance. Pick an approach, commit to it for the full recommended course, and give it time.
If you’ve been trying for more than a year without meaningful progress, stop spending money on more lacquers and see a podiatrist. It’s usually a straightforward appointment — and often resolves things quickly that home treatment couldn’t shift.
I wish I’d known that fifteen years ago. Would have saved me a lot of filing.
Last reviewed: March 2026 | This guide is for informational purposes. It does not constitute medical advice. Always consult a qualified podiatrist for diagnosis and treatment of foot conditions.
