The most painful and annoying sores to get around and in your mouth are cold sores. One of the best ways to prevent and treat cold sore outbreaks would be with an essential amino acid called lysine. Lysine is an amino acid your body needs to help absorb calcium so you can have strong bones, healthy teeth, hair, and skin, as well as proper collagen formation. Lysine also helps control the amount of another amino acid in your body called arginine which is an amino acid in your body that replicated the herpes simplex viruses which cause more cold sore outbreaks.