How Long Does It Take for Lamisil to Work? Plus, 4 More FAQs

Fungal skin or nail infections can be frustrating. Luckily, antifungal medications such as Lamisil (terbinafine) can help get rid of them. There are two main versions of Lamisil: topical products you apply to the skin and tablets that you take by mouth. And they each treat different fungal infections.

Lamisil AT (terbinafine 1%) is an over-the-counter (OTC) topical cream or spray. It treats a common fungal skin infection called ringworm. This includes ringworm of the groin (“jock itch”) and feet (“athlete’s foot”). Lamisil tablets (terbinafine 250 mg) are only available with a prescription. They’re prescribed to treat nail fungus.

If you’re using either form of Lamisil to treat a fungal infection, it’s normal to have questions about how it works and when you can expect to see results. Here, you’ll find answers to these and other frequently asked questions.

Good to know: Brand-name Lamisil tablets are no longer available. This medication only comes as a generic. But many people still call it Lamisil. For ease of reading, we’ll use the word “Lamisil” when referring to the prescription-only tablets.

1. How does Lamisil work?

Lamisil works by killing the fungus causing your skin or nail infection. Although you can see and feel symptoms of your infection, the fungus itself is invisible to the naked eye. Lamisil kills these tiny fungal cells by destroying their cell membranes, the part that holds the fungal cell together.

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But keep in mind that Lamisil doesn’t work for all types of fungal infections. For instance, it doesn’t kill the type of fungus that causes most vaginal yeast infections. If you’re self-treating with OTC Lamisil AT, you should only use it for the types of infections listed on the package.

2. How long does it take for Lamisil to work?

Patience is key when it comes to using Lamisil. Both topical and oral Lamisil will start killing some of the fungus right away. But it can take a while before you see noticeable results.

Fungal skin infections generally clear faster than nail infections. You may start to notice an improvement in skin infections, such as athlete’s foot, in as little as 1 week. If you’re not seeing any improvement after a week of use, contact a healthcare professional.

For nail infections, it may take several months after the fungus is cleared for you to see results. On average, it takes about 4 months for people to see healthy fingernails. And it takes about 10 months to see healthy toenails. This is because new, uninfected nails have to grow out after Lamisil has treated your infection. But rest assured that despite the long wait time, Lamisil is the most effective oral treatment for nail fungus.

3. How long do you have to use Lamisil?

How long you’ll use Lamisil will depend on the type of infection you’re treating. In general, you should use Lamisil AT for either 1 or 2 weeks. And you should take oral Lamisil for 6 or 12 weeks.

Below, you’ll find more details for how long to use each Lamisil product. You can also find these instructions on your prescription or OTC label. Contact your prescriber or pharmacist if you’re unsure how long to use it.

Good to know: Regardless of which form of Lamisil you’re using, you should finish the entire course of treatment. This helps ensure the infection is fully cleared. Stopping Lamisil too early can cause your infection to return and make repeat infections harder to treat.

Length of Lamisil AT treatment

Here’s how long you can typically expect to use topical Lamisil AT:

• Athlete’s foot (between the toes): Apply twice a day for 1 week.

• Athlete's foot (on the bottom or sides of the foot): Apply twice a day for 2 weeks.

• Jock itch: Apply once a day for 1 week.

• Ringworm: Apply once a day for 1 week.

Keep in mind that a healthcare professional may advise you to use Lamisil AT for longer than what’s listed on the package. Be sure to follow your prescriber’s instructions if they’re different from what’s listed here.

Lamisil AT cream and spray both contain the same active ingredient. But the spray hasn’t been studied for treating athlete’s foot on the sides or bottom of the foot. Consider using the cream version if you’re treating athlete’s foot in these areas.

Length of oral Lamisil treatment

Here’s how long you can typically expect to take Lamisil tablets:

• Fingernail fungus: Take 1 tablet by mouth once a day for 6 weeks.

• Toenail fungus: Take 1 tablet by mouth once a day for 12 weeks.

It’s a good idea to try to take your dose around the same time each day. This helps provide consistent amounts of medication to your body. Stomach upset is a common side effect of Lamisil tablets. Consider taking your doses with food to help lessen or prevent it.

4. How do you know Lamisil is working?

In short, you’ll know Lamisil is working if your symptoms are improving with time. And remember that with Lamisil tablets it can take several months after your last dose to see results. It’s a good idea to ask your prescriber if you need to follow up with them at all during treatment. For nail infections, they may want to see you after a few weeks to reevaluate your nail(s).

Give your healthcare team a call if at any point during treatment, your infection seems to be getting worse or spreading. You should also reach out if you’ve completed the recommended treatment and haven’t seen any improvement.

Keep in mind that experiencing side effects from Lamisil doesn’t mean the medication is working. You can still have side effects even if the treatment isn’t effective. You should primarily watch your symptoms for either improvement or worsening.

5. Can you use Lamisil cream on nails?

No, Lamisil AT cream doesn’t work well for treating nail infections. Nails are much thicker and harder than skin. Lamisil AT has trouble getting through the nail to kill the fungus living underneath.

If you’re interested in a topical treatment for nail fungus, ask your prescriber about a prescription nail polish, such as ciclopirox. These can be effective for mild to moderate nail infections. But keep in mind that they usually need to be applied every day for 48 weeks (almost 1 year) to work.

Good to know: Lamisil AT also doesn’t work well for treating scalp ringworm. Talk to your prescriber if you think you have a fungal scalp infection. Oral Lamisil would be a preferred treatment for this type of infection.

How to save on Lamisil

There are ways to save on prescription and OTC Lamisil, which are both available as generic medications. If your prescriber writes you a prescription for Lamisil AT, GoodRx may be able to help you save over 70% off the average retail price.

Generic Lamisil AT’s price at certain pharmacies may be as low as $6.35 with a free GoodRx coupon. And generic Lamisil tablets may cost as low as $12.34 for 30 tablets.

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Written by:

Tegan Smedley, PharmD, APh

Tegan Smedley, PharmD, APh, has 10 years of experience as a pharmacist. She has worked in a variety of settings, including retail, hospital, and ambulatory care.

Edited by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

Reviewed by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

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