Carnitine deficiency is a condition where the body lacks enough carnitine, a nutrient essential for transporting fatty acids into the mitochondria, where they are converted into energy. This deficiency can lead to symptoms such as muscle weakness, fatigue, and heart problems, as the body struggles to utilize fat for energy. There are two main types of carnitine deficiency: primary, which is genetic and affects the body's ability to produce carnitine, and secondary, which can result from certain medical conditions or medications. Treatment often involves dietary changes and supplements to restore carnitine levels and improve overall health.