One of Ashwagandha’s best known benefits is to cut back levels of cortisol, the stress hormone associated with the physiological effects of stress. While we need some cortisol to keep alive, chronic stress can lead to persistent or extreme elevations in cortisol, with negative effects on blood glucose regulation, blood lipids, body composition, hormone balance, digestion, sleep, immune function, and cognitive health.
In a 2005–06 multi-phase, randomized, double-blind, placebo-controlled clinical trial, those who took ashwagandha had a 30.5% reduction in serum cortisol compared to those that took placebo. They also had a 32.5% escalation in levels of dehydroepiandrosterone (DHEA), the hormone that counterbalances the activity of cortisol.