Do not use if you are pregnant or breastfeeding, have had a heart attack/myocardial infarction or have primary systemic L-carnitine deficiency or secondary L-carnitine deficiency (inborn errors of metabolism) for which supplementation is prescribed/monitored by a health care practitioner. Consult a health care practitioner prior to use if you have celiac disease, fat malabsorption, vitamin A, D, or E deficiency, diabetes, if you have cardiovascular disease and are attempting to increase physical activity, have renal/kidney disease, are following a low protein diet or are taking blood thinners, digoxin, antidepressant medications, or medications for cardiovascular diseases or erectile dysfunction. Consult a health care practitioner if your cardiovascular condition worsens. Some people may experience gastrointestinal discomfort (such as diarrhea). Some people may experience insomnia, anxiety, or headaches, in which case, discontinue use. May cause nausea, dry mouth, fatigue, and hypersensitivity (allergy). Use with caution if you have allergies to members of the Scrophulariaceae (figwort) family. If you experience sweating, paleness, chills, headaches, dizziness and/or confusion, discontinue use and consult a health care practitioner as these may be symptoms of serious low blood sugar.