What are some of the main medical treatments for cold sores?

There is no cure for the herpes simplex virus (HSV) infection that causes cold sores, but treatment with oral and/or topical (applied to the skin) antiviral medication at the first sign of an outbreak can reduce the outbreak’s duration, speed healing, and reduce the amount of viral shedding. Oral antivirals, such as valacyclovir, are more effective than topical antivirals.^[1][2][3] In people who have frequent outbreaks or are immunocompromised, oral antivirals are sometimes taken long-term to reduce the frequency of outbreaks.^[2][4][5] Because UV exposure is known to trigger outbreaks, sunscreen is sometimes recommended as a preventative. However, while there is evidence that sunscreen may reduce the risk of outbreaks triggered by artificial (experimental) UV exposure, that evidence is very low quality, and there is even some low-quality evidence that sunscreen might slightly increase the risk of outbreaks triggered by sunlight exposure.^[5]