From all seven studies which measured plasma levels, cortisol secretion was significantly reduced by between 11% and 32.63%.
The Italian researchers summarise: “Supplementation with WS for a period ranging from 30 to 112 days appears to have a stress-reducing effect by lowering cortisol levels in stressed individuals.”
Yet, they highlight that further research should investigate the long-term effects of WS supplementation to conclude on its use within potential interventions for stress reduction.
Ashwagandha and stress
There has been an increasing prevalence of mental health issues over recent years, resulting from the increasing pressures and stress levels of the modern day. Consumers are increasingly seeking natural herbal products to support the mind.
WS, also known as Ashwagandha or Indian Ginseng, has received particular attention due to its potent bioactive composition boasting antioxidant, anti-inflammatory, immunomodulatory, and anti-stress activities.
Many products and supplements containing WS promote benefits to anxiety levels, sleep health, and athletic performance. With its growing popularity, there is an increasing need to further understand the biological properties of the supplement to validate and optimise its use, with a lack of conclusive evidence explaining the precise mechanisms of action.
Thus, the present systematic review aimed to collate the available evidence on the effectiveness of WS on reducing cortisol levels in stressed human participants.
The databases of PubMed, EMBASE, CENTRAL, Google Scholar, and Scopus were searched using specified key words and inclusion criteria. Nine studies were included in the review as a result of the search, involving subjects experiencing an array of stress levels.
It was noted that there was significant heterogeneity between included studies in terms of design, formulation, and dosage, with treatment durations ranging from 30 to 112 days. Despite this, it was observed that WS supplementation decreased cortisol secretion with no significant adversities.
Within the studies measuring plasma cortisol levels, all seven displayed significant reductions between 11% and 32.83%.
Yet, it was identified that none of the included studies investigated the potential impact of cortisol reduction on adrenal function and the long-term effects.
The findings suggest that brief supplementation with WS may result in a stress-reduction effect, yet the researchers highlight the research does not investigate the long-term effects of supplementation and the potential impact on hormonal levels.
Hypothesising the mechanisms of action, the researchers explain: “Withaferin A might affect circulating cortisol levels presumably owing to a direct interaction with glucocorticoid receptors (GR) in the brain, but other WS bioactive substances could also modulate the levels of this hormone.
“The effect on cortisol levels of WS may be also an indirect effect of its sedative and hypnotic activities. The HPA axis response to stress can also be regulated by gamma-aminobutyric acid (GABA) signalling,” they add.
The report emphasises the need for further research to understand the long-term effects of supplementation with WS and the mechanisms of action.
“Effects of Withania somnifera on Cortisol Levels in Stressed Human Subjects: A Systematic Review”
by Matteo Della Porta, Jeanette A. Maier and Roberta Cazzola