New cold sore cream shows promise in small study
NCT ID NCT06558838
First seen Jun 25, 2026 · Last updated Jun 27, 2026 · Updated 1 time
Summary
This study tested a cream containing acyclovir and penciclovir against an over-the-counter cream (Abreva) for preventing cold sores caused by UV light. Forty adults with a history of cold sores were exposed to UV light to trigger an outbreak, then treated with one of the creams. Researchers tracked whether the cold sore progressed to a blister and how quickly it healed.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- acyclovir-penciclovir cream
- What this could lead to
- If it works, this could point toward a more effective cream for preventing cold sores from forming after sun exposure.
- What could go wrong
- This is a small, early pilot study with only 40 people, so results may not apply to everyone. The cream may not work better than the existing treatment.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 2
Tests whether the treatment actually works, and watches for side effects, in a larger group.
- Participants
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40 people
The number who actually took part.
- Started
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Aug 2024
- Finished
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Nov 2025
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 to 80 years
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
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Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: * Understands the requirements of the study and provides written informed consent prior to undergoing any study-related procedures. * Subject is a male or female between the ages of 18-80 years old, inclusive. * Fitzpatrick skin type II or III. * History of at least one year of herpes labialis induced by UV exposure. * Able to recall exact location of most common or most recent outbreak. * History of at least 50% of cold sore outbreaks occurring with UV (sun) exposure. * At least 1 HSV-1 outbreak within the past 12 months. * Experiences prodromal symptoms before HSV-1 outbreaks. * Subject is willing and able to comply with protocol-specified dosing, visits to the clinic and tracking of pain. Exclusion Criteria: * Outbreak \<2 weeks prior to enrollment. * History of herpes simplex vaccine. * On antiviral suppression within the past 30 days. * Requires more than acetaminophen for pain from recurrent HSV outbreaks. * On any systemic or topical steroid, immune suppressant or chemotherapeutic agent within the past 14 days. * Use of tanning beds, history of sunburn, or beach vacation \<2 weeks prior to enrollment. * History of photosensitivity, lupus erythematosus, or current use of a highly photosensitizing medication in the opinion of the investigator. * Current immunosuppressed state due to underlying disease (i.e. HIV infection) concomitant treatment (i.e. chemotherapy). * Current upper respiratory tract infection or any active illness that could trigger cold sores or affect overall health of the patient or the assessment of the study agent. * Pregnant or intending to become pregnant during the study. * Abnormal skin conditions in the area of the recurrent HSV1 outbreaks. * Enrolled in another clinical trial within the past 30 days. * On any analgesics or NSAIDs that cannot be stopped during the study. * Alcohol or drug abuse.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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University of Utah MidValley Dermatology
Murray, Utah, 84107, United States
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