If you are like a lot of people, you may have never heard of carnitine but this important nutrient is critical for our body's ability to optimally burn fat required for energy. L carnitine levels decrease with age, contributing to aging and a decline in mitochondrial function. The list doesn't stop there. L carnitine supports: Joint health L carnitine has been shown to support joint comfort Safety, Tolerability and Symptom Outcomes Associated with l Carnitine Supplementation in Patients with Cancer, Fatigue, and Carnitine Deficiency: A Phase I II Study ScienceDirect Comparison of L carnitine levels in different studied groups. Download Table The adverse effects of long term l carnitine supplementation on liver and kidney function in rats L Liu, D M Zhang, M X Wang, C Y Fan, F Zhou, S J Wang, L D Kong, 2015