Mitochondira are organelles in cells that provide oxygen and energy. Their decay and death leads to our decay and death over time. Astragalus protects them! Here is research to prove it: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3291990/ I have found that with chronic fatigue it helps to take 3 capsules 2X a day - not near bedtime. Really chronic fatigue is just adrenal weakness. See Dr. Frank Shallenberger's Youtube vids to learn more about that.