Fungal nail infections — treatment and timelines
Reviewed by the My London Pharmacy clinical team, Zeenah Araim, Pharmacist Independent Prescriber
·29 July 2026
·7 min read
Quick answer
A fungal nail infection makes nails thickened, discoloured and brittle, usually starting at the edge of a toenail. Treatment options range from a topical nail lacquer such as Amorolfine to oral antifungals like Terbinafine for more stubborn cases. Nails grow slowly, so full recovery can take several months to a year.
What a fungal nail infection is
A fungal nail infection, known medically as onychomycosis, is a common condition where fungi infect one or more nails, most often the toenails. It usually begins at the edge or tip of the nail and gradually spreads. The same fungi that cause athlete's foot are frequently responsible, which is why the two conditions often occur together.
Fungal nail infections are more common with age, in people who sweat heavily, and in those whose feet are often warm and damp, such as inside trainers. They are generally not serious, but they can be persistent and, for some people, uncomfortable or embarrassing. Left untreated they tend not to clear on their own and can slowly affect more of the nail. Because the infection develops so gradually and is usually painless at first, many people live with it for years before deciding to do anything about it, by which time more of the nail may be involved. Knowing that early, limited infections are easier to treat than established ones is a good reason not to leave it too long once you notice a change.
Recognising the signs
Fungal nail infections develop slowly and are often painless at first, which is why they can go unnoticed for a while. Typical signs include:
- Discolouration, with the nail turning white, yellow, green or brown
- Thickening of the nail
- Brittle or crumbly edges
- A distorted or misshapen nail
- Debris building up under the nail
In some cases the nail may lift away from the nail bed or become tender if it thickens enough to press on the toe. Because other conditions such as psoriasis or a past injury can look similar, it is worth confirming the cause, as this guides the right treatment.
Whether and when to treat
Not every fungal nail infection needs treatment. If it is mild, not bothering you and not affecting many nails, you may choose simply to keep it in check with good foot care. However, treatment is worth considering if the nail is uncomfortable, if the appearance troubles you, if it is spreading, or if you have a condition such as diabetes that makes foot problems more significant.
Treating athlete's foot at the same time is important, as an untreated skin infection can quickly reinfect the nail. Good foot hygiene, keeping feet dry, and not sharing towels or nail tools all support whatever treatment you choose.
Topical treatment options
For mild infections affecting only the end of the nail or a small number of nails, a topical antifungal nail lacquer is often the first choice. Amorolfine is a widely used lacquer that is painted onto the affected nail, usually once or twice a week, after gently filing the surface. It works gradually as the healthy nail grows out beneath it.
Another topical option is Trosyl, a nail solution applied more frequently, which can be suitable for certain infections. Topical treatments avoid the need for tablets, but they require patience and consistency, as they can take many months to work and are less effective when the infection has reached the base of the nail.
Oral treatment for stubborn infections
When several nails are affected, when the infection reaches the root of the nail, or when topical treatment has not worked, a clinician may consider an oral antifungal. Terbinafine taken as a tablet is the most commonly used option for toenail infections and works from within as the new nail grows. A course typically lasts several months, and a clinician will check that it is suitable alongside any other medicines you take.
An alternative such as Itraconazole may be used in certain situations, sometimes in a pulsed pattern of on-and-off dosing. Oral treatments tend to be more effective than topical ones for established infections, but they are used carefully because they can occasionally affect the liver, so a clinician will weigh up whether they are right for you.
Realistic timelines and expectations
Patience is essential with fungal nails, because the improvement you see depends on the slow speed at which nails grow. Fingernails grow out over roughly six months, while toenails can take twelve to eighteen months to fully replace themselves. This means that even with successful treatment, a healthy-looking nail takes a long time to appear.
During treatment the infected part of the nail does not become clear; instead, new, healthy nail grows in from the base. Judging success by watching the new growth rather than the old nail helps set realistic expectations. Some thickening or discolouration may remain even after the fungus is gone, particularly if the nail was previously damaged.
It can be encouraging to take a photograph of the nail when you start treatment, so you have something to compare against as the months pass. Gently filing down thickened areas can improve comfort and, for topical treatments, helps the product reach the nail more effectively. If, after completing a full course of treatment, you see no healthy new growth coming through at the base of the nail, that is a reason to seek review rather than simply continuing, as the diagnosis or the choice of treatment may need reconsidering.
What makes a fungal nail infection more likely
Some people are more prone to fungal nail infections than others, and knowing the risk factors helps with both treatment and prevention. The fungi that cause these infections flourish in warm, damp conditions, so anything that keeps the feet moist for long periods increases the risk. Wearing enclosed shoes or trainers for long hours, having sweaty feet, and using communal changing rooms and pools are all common contributors.
Age is another factor, as nails grow more slowly and are more easily damaged over time, which is why fungal nail infections become more common in later life. A previous nail injury, such as a knock or repeated pressure from tight footwear, can create a way in for the fungus. Certain health conditions, including diabetes and problems with circulation or the immune system, also raise the risk and can make infections more troublesome, which is why people in these groups are usually advised to seek treatment rather than leave an infection untreated. Having athlete's foot makes a nail infection more likely too, because the same fungus can spread from the surrounding skin into the nail.
Preventing it coming back
Fungal nail infections can return, so prevention matters as much as treatment. Keep your feet clean and dry, especially between the toes, and dry them thoroughly after washing. Wear breathable footwear, change socks daily, and let shoes air between wears. Treating athlete's foot promptly stops it spreading back to the nails.
Avoid walking barefoot in communal areas such as changing rooms and pool sides, and do not share nail clippers, files or towels. If you are prone to reinfection, disinfecting or replacing old footwear can help. A clinician can advise on suitable treatment and prevention based on your circumstances, and all treatment is subject to suitability.
It is also worth remembering that not every discoloured or thickened nail is fungal. Psoriasis, past injuries, and simple age-related changes can all alter the appearance of a nail, and treating these as if they were fungal will not help. Where there is any doubt, a sample of the nail can be tested to confirm the cause before starting a long course of treatment, which is particularly sensible before committing to oral medication. Getting the diagnosis right at the outset saves months of treatment that might otherwise be aimed at the wrong problem, and lets you and a clinician choose the approach most likely to give you a healthy nail in the long run.
Frequently asked questions
How long does it take to treat a fungal nail infection?
Because nails grow slowly, toenails can take twelve to eighteen months to look normal again even with effective treatment. You judge progress by the healthy new nail growing from the base.
Can I treat a fungal nail infection at home?
Mild infections affecting the tip of the nail can often be treated with a topical nail lacquer, which is available for home use. More extensive infections may need oral treatment, which a clinician can assess.
Will a fungal nail infection go away on its own?
It is unlikely to clear without treatment and tends to spread slowly over time. Treating it also helps prevent it passing to other nails or to other people.
Is a fungal nail infection contagious?
Yes, it can spread to other nails and to other people, often through shared towels, footwear or communal floors. Good foot hygiene reduces the risk.
Do I need tablets or is a lacquer enough?
A lacquer can work for mild infections at the end of the nail, while tablets are usually more effective when several nails or the nail base are involved. A clinician can advise which is suitable for you.