Yes, cold sores are contagious, and they spread most easily from the first tingle until the sore has fully scabbed and healed.
Cold sores come from herpes simplex virus, usually HSV-1, which passes through direct contact with the sore, saliva, or the skin around the mouth. Kissing, sharing drinks, utensils, lip balm, towels, or razors, and oral sex can all pass it along, and the virus sometimes sheds when your lips look normal. Once you have the virus it stays in your body and can reactivate later, so the goal is limiting contact during an outbreak rather than curing it. Wash your hands after touching your lips, skip lip contact with others until healing is done, and never touch your eyes after touching a sore. Antiviral creams or pills started at the first tingle can shorten an outbreak, and a clinician can prescribe them.
How cold sores spread
Common questions
Is cold sores contagious?
Yes. Cold sores are caused by herpes simplex virus, usually HSV-1, and it spreads through direct contact with the sore, saliva, or the skin around the mouth. You are most contagious from the first tingle through the blister and weeping stages until the scab heals, though the virus can also spread with no visible sore. Kissing, sharing drinks, utensils, lip balm, towels, or razors, and oral sex can all pass it on. Wash your hands after touching your lips, keep your hands away from your eyes, and avoid contact with newborns, people with eczema, and anyone with a weakened immune system while a sore is active.