Withanolides
Main steroidal lactones of ashwagandha (Withania somnifera). They are responsible for its documented adaptogenic effects on stress, cortisol, sleep and anxiety. The withanolide content (often 1.5% to 5% in standardised extracts such as KSM-66 or Sensoril) is the essential quality criterion of an ashwagandha supplement.
Never use a dietary supplement without the advice of a healthcare professional. Overdoses as well as deficiencies are not without risk.