Serum L Carnitine Levels Are Associated With First Stroke in Chinese Adults With Hypertension Stroke Comparison of L carnitine levels in different studied groups. Download Table Table 1 from The effects of L carnitine levels on L Carnitine Oral Bioavailability NOW l Carnitine Supplement Safety, Tolerability and Symptom Outcomes Associated with l Carnitine Supplementation in Patients with Cancer, Fatigue, and Carnitine Deficiency: A Phase I II Study ScienceDirect 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