Without enough NAD, your cells cant generate the energy needed for various physiological processes, causing fatigue, among other issues
Journal of strength and conditioning research, 36(8), 21982203
a control group (each rat was intraperitoneally injected with 0.5 ml of 0.9% NaCl daily for five days), HPE-treated group (HPE, 10.08 mg/Kg b.w/day, was subcutaneously injected for two weeks), MTX-treated group (MTX, 5 mg/Kg b.w/day, was intraperitoneally injected for five days) and MTX and HPE-treated group (Both MTX and HPE were injected to rats at the same time with the same doses, duration and injection routes in MTX and HPE groups)
Table of Contents What Is CoQ10 and How Does It Work in the Body
Dixon LK, Stahl K, Jori F, Vial L, Pfeiffer DU