Cold Sores

What causes cold sores?

Cold sores, also known as fever blisters, are caused by a herpes simplex virus (usually HSV-1). Once you’re infected with the virus, it stays in your neurons and can be reactivated throughout your life. Most people with oral herpes are infected in childhood.

When is the best time to start cold sore treatment?

Antiviral cold sore medications work best when taken within 3 days of symptoms starting. When taken at the start of an outbreak, these medications can reduce the severity of your symptoms, shorten your outbreak, and lower your risk of spreading cold sores.

Is online treatment right for me?

• You’re 18–64

• You’ve had cold sores before

• No kidney disease, seizure disorder, or immune suppression