A bit more info... It's an amino acid that helps decrease the amount of arginine in your system (you get arginine from nuts, which are a known trigger for cold sores). L-lysine is found in meat and eggs, mostly. From what I've found in my research, the amount of l-lysine in our food has decreased over the years.
Treat it from the inside as well with L-Lysine. Taking 1000-2000 mg a day will keep cold sores at bay, and will also help against shingles. Interestingly, it has also shown some promise in fighting the imaginary COVID crap (https://wholefoodsmagazine.com/columns/vitamin-connection/lysine-reported-to-halt-coronaviruses-an-interviw-with-bill-sardi/). Some brands are better than others--make sure it's from a trusted company (I switch between Blue Bonnet and Pure Encapsulations.
A bit more info... It's an amino acid that helps decrease the amount of arginine in your system (you get arginine from nuts, which are a known trigger for cold sores). L-lysine is found in meat and eggs, mostly. From what I've found in my research, the amount of l-lysine in our food has decreased over the years.