L Carnitine is Underrated. New Meta Review Reminds Us Why. 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 reduces hyperthyroidism symptoms Exploring the potential anti thyroid activity of Acetyl L carnitine: Lactoperoxidase inhibition profile, iodine complexation and scavenging power against H2O2. Experimental and theoretical studies ScienceDirect Carnitine and Thyroid Disease page 1 Life Extension