How effective are creams and tablets for the treatment of cold sores?

Photo of a woman using an ointment

Antiviral medications like acyclovir or penciclovir can make cold sores go away about one day sooner. If you decide to use one, it’s important to start the treatment as soon as you notice the first signs of a cold sore.

Cold sores are bothersome. They can greatly affect your quality of life, particularly if you have them several times a year. Antiviral drugs can speed up the healing process somewhat and reduce the severity of the symptoms.

It’s important to use these drugs properly: The treatment should be started within 24 hours of the first symptoms arising – the sooner, the better. This is true for tablets, as well as for medication that is applied from the outside (topical medication). If the treatment is started later, it might not help anymore because the viruses will have already spread along the nerve fibers. Topical cold sore medications can be bought in pharmacies without a prescription, and antiviral medications are only available with a prescription.

Topical medications

Creams, gels and ointments containing the drugs acyclovir or penciclovir are available in pharmacies without a prescription. Studies have shown that they can make cold sores go away about one day sooner. They can also reduce the severity of symptoms somewhat.

For them to be able to work, they have to be applied to the affected area every 2 to 3 hours during the daytime. The treatment lasts five days.

How effective is the combination drug?

There is also a combination drug (trade name: Zovirax Duo) that contains both acyclovir and a mild steroid. One study looked into whether this combination drug can lower the risk of cold sore blisters and scabs forming. The drug was either compared with acyclovir used alone or with a non-medicated cream (placebo). The people in the study had an average of 5 to 6 cold sores per year, and their cold sores often crusted over and formed scabs. They started using the treatment as soon as they noticed the first signs of a cold sore developing.

The study suggests that the combination of acyclovir and a steroid is somewhat more effective than acyclovir alone. Expressed in numbers, it was found that blisters and scabs formed in

  • 65 out of 100 people who used acyclovir alone, and in
  • 58 out of 100 people who used the combination drug.

In other words: Compared to acyclovir alone, the combination drug prevented the development of blisters and scabs in an extra 7 out of 100 people.

Topical treatments for cold sores can sometimes irritate the skin a bit, but no serious side effects occurred in the studies.

Oral medications

The antiviral drugs acyclovir, famciclovir and valacyclovir are also available in the form of tablets. Research has shown that treatment with these tablets can make cold sores go away about one day sooner in people who are otherwise healthy.

Antiviral tablets are well tolerated. In studies, they weren’t found to cause more side effects than placebo medication did. But people who have kidney failure might have to use a lower dose.

One advantage of tablets is that – unlike ointments and creams – they only have to be taken once or twice a day. Depending on the type and dose of the tablets, the treatment lasts 1 to 7 days.

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Please note that we do not provide individual advice on matters of health. You can read about where to find help and support in Germany in our information “How can I find self-help groups and information centers?

Updated on March 23, 2022
Next planned update: 2025


Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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