What is lysine?
Lysine, also known as L-lysine hydrochloride, is an essential amino acid. It is a necessary nutrient for both humans and cats, but the body cannot produce it on its own. It must be obtained through a daily diet and nutritional supplements. As an amino acid, it is an essential component of protein. This nutrient plays a vital role in proper growth and development. 
Why cats need lysine
Due to their unique physiological structure, cats cannot synthesize lysine but have a high amount of arginine. Cats are particularly susceptible to feline rhinotracheitis (feline herpesvirus), the pathogen of which replicates and spreads using arginine. Cats with feline rhinotracheitis will exhibit symptoms such as sneezing, runny nose, coughing, tearing, conjunctivitis, decreased appetite, and lethargy; in severe cases, it can lead to death.
Lysine can inhibit the replication and development of rhinotracheitis virus (RTV). Cats are highly susceptible to this virus because of a deficiency in lysine. Once a cat is infected with Rhinotracheitis, it severely harms its health. To prevent Rhinotracheitis infection, owners should try to reduce the amount of arginine in their cat's body. Lysine can counteract the effects of arginine, so it's important to supplement cats with lysine.
How to supplement lysine for cats
There are many lysine powders available on the market. Generally, the dosage of lysine is calculated based on the cat's weight. Taking Miaoxiang lysine as an example, feed 3 grams to cats weighing less than 2.5kg, 5 grams to cats weighing 2.5kg to 5kg, 10 grams to cats weighing 5kg to 15kg, and 15 grams to cats weighing more than 15kg. Feed lysine once or twice a day.
For routine care (or for cats with a history of feline herpesvirus infection), lysine can be given every 2-3 days. If the cat has feline herpesvirus infection, it needs to be given lysine every day until it is fully recovered.
