Amazon.com: 5% Nutrition Rich Piana Liquid L Carnitine 3150 Premium 4 Source Blend + GBB, The Super Carnitine (Mandarin Orange) : Health & Household L Carnitine Linus Pauling Institute Oregon State University Does Carnitine from Red Meat Cause Heart Disease? Diagnosis Diet Steak isn't bleeding. That red liquid you see is mostly water mixed with myoglobin, a protein found in muscle that stores oxygen. When steak cooks, the muscle fibers tighten and release moisture.