Sleep debt, iron or B12 deficiency, low vitamin D, untreated sleep apnea, thyroid dysfunction, depression, excessive alcohol and sedentary behaviour explain most male fatigue.
A basic panel (CBC, ferritin, B12, D, TSH, fasting glucose) rules out the common medical causes.
L-Carnitine and Niacin in Maxorin support mitochondrial energy production, but they cannot fix apnea or a thyroid problem.