Adrenal hypofunction associated with ashwagandha (Withania somnifera) supplementation: a case report

Abstract

Objective: The use of herbal medicinal supplements has gained huge popularity world-wide, but scientific evidence of their effectiveness and safety remains scarce. Ashwagandha (Withania somnifera) is one such product, claimed to alleviate pain and anxiety by lowering circulating cortisol levels. Withanolides, which are the principal bioactive compounds of ashwagandha, are naturally occurring steroids and may suppress adrenal function. Here, we describe the effect of ashwagandha on adrenal function of a 41-year-old woman with a low body mass index and who suffered chronic pain and lethargy. Methods: Adrenal function was assessed by the short Synacthen test (SST) during and after treatment with ashwagandha supplementation. Results: Whilst taking daily ashwagandha supplement (21.4 mg of Withanolides), for ten weeks, a SST showed a minimal response to 250 μg of an intramuscular injection of Synacthen (tetracosactide): cortisol levels at T0min = 287 nmol/l, T30min = 289 nmol/l, and T60min = 328 nmol/l; from a morning baseline cortisol level of 480 nmol/l prior to taking the supplement. Ashwagandha was discontinued for two weeks, and a repeat SST was performed showing a completely normal adrenal response: cortisol level at T0min = 275 nmol/l, T30min = 623 nmol/l and T60min = 674 nmol/l. Conclusion: Ten weeks of ashwagandha supplementation was associated with adrenal hypofunction, which was reversible after a two-week break. Individuals taking ashwagandha should be aware of this potentially detrimental effect. Future studies are suggested to assess whether long-term treatment with ashwagandha could lead to permanent suppression of adrenal function, and to elucidate the effects of ashwagandha compounds on adrenal steroidogenic pathway and hypothalamic–pituitary–adrenal axis.