l carnitine l tartrate syrup NOW Foods Sports Nutrition, L-Carnitine Liquid, Triple Strength 3000 mg, Citrus, 16-Ounce : Health & Household The Vitamin Shoppe Raspberry L-Carnitine
Description
But some people need it more than others

It doesnt contain any stimulants or prohormones, so it should not create any false positives

(PubMed) van Dam DG, Beijers AJ, Vreugdenhil G

It is always good to talk to a doctor before starting any new supplement
Carnitine carries long-chain fatty acids into mitochondria to be oxidised for the creation of free energy and also takes the role of clearing metabolic waste from cells to assist energy metabolism

Cruciani R, Dvorkin E, Homel P, Malamud S, Culliney B, Lapin J, et al
