Resveratrol is a compound that is typically found in red grapes, and is known for its many health related benefits that arise from its ability to attack pathogens and viruses. It has also proven to be effective against the herpes simplex virus, which is what causes your cold sores.
A study by the Northeastern Ohio University demonstrated that resveratrol cream applied anywhere from two to five times a day was effective at suppressing the formation of cold sores if it was used soon enough after becoming infected, typically less than six hours. Indeed, it was shown to be as effective as some prescription strength creams, and without any side effects. Their conclusion was that resveratrol is effective in controlling the virus that leads to the formation of cold sores.
Resveratrol is available as a nutritional supplement, and there is also a prescription strength cream which is available only with your doctor’s recommendation. You should discuss the use of this product with your doctor in any case, because it’s still not generally accepted as a cold sore treatment.