Quest L-Lysine is an essential amino acid that the body does not make. This means that adequate levels need to be obtained from food and supplementation. L-lysine is a building block of protein structures within the body, especially muscle and skin protein structures and bones. L-lysine works in balance with the amino acid L-arginine, and helps to prevent a high L-arginine environment and decreases the occurrence of herpes viruses such as those seen with cold sores. High strength Natural L-lysine form Directions: As a food supplement take one to three tablets per day with food. For maintenance take one tablet per day. For acute phases, take one tablet three times per day. Ingredients L-lysine Hydrochloride, Silicified Microcrystalline Cellulose, Microcrystalline Cellulose, Precipitated Silicon Dioxide, Magnesium Stearate, Croscarmellose Sodium, Glazing Agent: Hydroxypropylmethylcellulose Dairy Free Gluten Free Nut Free Vegan Vegetarian