Does lysine work for cold sores, and is it in Reviralis?

Lysine is an amino acid found in protein foods like meat, fish, eggs and dairy, and it is sold as a supplement because of an old idea that it may interfere with cold sore viruses.

Cold sores come from HSV-1, according to Mayo (Mayo Clinic, Cold Sore Symptoms and Causes). The idea about lysine began with lab work and small studies. Lab findings do not tell you what happens in a person, so the question went to trials.

A plain label check: the Reviralis Supplement Facts lists 22 vitamins and minerals and a blend of 18 names. Lysine is not one of the 40. We mention it because many visitors search for it next to our brand.

Treat any supplement claim about cold sores as a question, not a fact, until a good trial backs it.

The FTC says health claims need competent and reliable scientific evidence, generally randomized controlled trials (FTC, Health Products Compliance Guidance). A product that implies it prevents a disease can be treated as a drug. We quote the sales page's outbreak wording and never repeat it as fact, because the label itself never names herpes.

Ask a clinician or pharmacist whether either one fits your medicines and conditions.

The Reviralis label asks anyone with a medical condition, seizure history, or prescription medicine to talk to a provider first. Read the benefits page for the claims side by side with the label. Lysine is also one reason people ask about antiviral medicine and supplements.