Common side effects of taking lysine are abdominal pain and loose bowel movements. This dietary supplement may also trigger symptoms of a severe allergic reaction, such as hives, breathing difficulty and inflammation of the throat, face, lips and tongue. People who experience any of these signs are advised to seek emergency medical treatment, states Everyday Health.
The human body is unable to naturally produce lysine, which is a type of amino acid. This essential nutritional component, which is required for optimal growth, can only be derived from foods or supplements. Although the majority of people get adequate lysine through food intake, some may need to supplement this essential amino acid.
Lysine is also known to be effective against certain medical conditions and in the promotion of calcium absorption. However, as with other dietary supplements, some uses of lysine are not regulated by the United States Food and Drug Administration. If taken without the guidance of a health care specialist, undesirable side effects may occur.
Elevated doses of lysine may result in gallstone formation, notes the University of Maryland Medical Center. Instances of kidney impairment, including renal failure and Fanconi's syndrome, have also been documented. Patients with pre-existing kidney or liver illnesses are advised to consult their physicians before dosing on lysine supplements. Expectant and lactating mothers are also advised to avoid using lysine without consent from a doctor.