Widely referred to as Indian Ginseng, this root has been trusted and used in traditional Ayurvedic medicine. Withania somnifera is a functional adaptogen, in that it has shown the ability to adapt to the individual levels of  stress  and requirements of  energy, stamina and vigour. It also contributes to improvement and stability of immunity.
All these qualities are crucial in the development of mental faculties and individual performances.

Research references

b)    Gupta A, et al. Efficacy of Withania somnifera on seminal plasma metabolites of infertile males: A proton
NMR study at 800MHz. J Ethnopharmacol. (2013)
c)      Ambiye VR, Langade D, Dongre S, Aptikar P, Kulkarni M, Dongre A. Clinical Evaluation of the
Spermatogenic Activity of the Root Extract of Ashwagandha (Withania somnifera) in Oligospermic Males:
A Pilot Study. Evidence-based Complementary and Alternative Medicine ( 2013)
d)      Mamidi P, Thakar AB. Efficacy of Ashwagandha (Withania somnifera Dunal. Linn.) in the management of
psychogenic erectile dysfunction. Ayu. (2011)
e)       Ahmad MK, et al. Withania somnifera improves semen quality by regulating reproductive hormone levels
and oxidative stress in seminal plasma of infertile males. Fertil Steril. (2010)
f)       Mahdi AA, et al. Withania somnifera Improves Semen Quality in Stress-Related Male Fertility. Evid Based
Complement Alternat Med. (2009)
g)      Zahra Kiasalari, Mohsen Khalili, Mahbobeh Aghaei. Effect of withania somnifera on levels of sex hormones
in the diabetic male rats. International Journal of Reproductive Biomed. (2009)