As a stress reducer, ashwagandha works by reducing the body’s levels of cortisol – a hormone that is linked to stress response. A healthy person experiences a natural rhythm of higher cortisol levels in the mornings as the hormone helps them wake up, and lower cortisol levels in the evenings as the hormone helps them relax and prepare for sleep. The stress-reducing effects of ashwagandha are not immediate, but can be felt within a couple hours.