Ashwagandha root extract is a perennial shrub cultivated in India and China.  It’s a medicinal ayurvedic herb used for thousands of years for its ability to release tension, improve breathing, reduce stress and aid in fertility. Its name comes from the Sanskrit language and means ashva-‘horse’ and gandha-‘smell’. The root has a strong smell that is described as horse-like. Its botanical name is Withania somnifera, however it’s also known as winter cherry or gooseberry. Its primary activity comes from the standardization of withanolides which are triterpene lactones.



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In preclinical studies, Withania Somnifera has shown anti-microbial, anti-inflammatory, anti-tumor, anti-stress, neuroprotective, cardioprotective, and anti-diabetic properties. (8). Additionally, it has demonstrated the ability to reduce reactive oxygen species, modulate mitochondrial function, regulate apoptosis, reduce inflammation and enhance endothelial function.(8)  Several studies have also looked at the efficacy of this herb for infertile men (5, 6, 7).  These studies reviewed Withania somnifera which showed significant improvement on serum hormonal profile, semen volume and sperm concentration. This evidence suggests that the mechanism of action of Withania somnifera may improve recovery from overtraining since overtraining results in low testosterone and low semen motility.


Though there are dozens of studies dating back 50 years, over the last 10 years eight separate clinical studies have shown the efficacy of this herb as it pertains to endurance athletes. Much like other adaptogenic herbs like Rhodiola Rosea, its primary benefit comes from its ability to modulate cortisol (stress). Ashwagandha has been shown to improve resistance to stress including a reduction in cortisol by 30%. (9) Secondary benefits include improvement in VO2max, improvement in substrate utilization (fat burning) and performance. (1,2,3,4) Studies indicate this is a systemic dose dependent ingredient that should be consumed daily for 8 weeks or longer.


40 elite male cyclists participated in the experimental study. Half the cyclist were randomly placed in a placebo group versus a treatment group where they consumed ashwagandha for 8 weeks. VO2max, respiratory exchange ratio (RER), and total time to exhaustion was measured on day 1 and at 8 weeks. The treatment group showed significant improvement in VO2max (p<.001), METS (P<.001) and time to exhaustion (P<.001). (3)

50 healthy male and female athletic adults participated in this double-blind, randomized, placebo controlled study. VO2 was measured during a 20m shuttle run test. Results showed a greater increase (p<0.0001) in mean VO2max with ashwagandha versus placebo at 8 weeks and 12 weeks. Study shows ashwagandha enhances cardiorespiratory endurance in healthy athletic adults. (1)


57 young male subjects participated in an 8-week randomized double-blind placebo controlled study. Subjects in the treatment group consumed ashwagandha for 8 weeks while the control group consumed a placebo. Compared to placebo, the treatment group had significant increases in muscle strength on bench-press, leg-extension, and muscle size. The ashwagandha group also had significant reduction in muscle damage as indicated by the stabilization of creatine kinase and improvement in testosterone levels. (2)

A 2010 study using 40 normal healthy subjects, looked independently at the efficacy of both Withania somnifera and Terminalia Arjuna.  This double blind study separated the subjects into four groups.   One group consumed Withania somnifera, a second group consumed Terminalia Arjuna, a third group consumed both herbs and a fourth group consumed a placebo.    After 8 weeks of supplementation significant improvements were seen with all three test groups.  The group using Withania somnifera increased maximum velocity, power and VO2max. (4).


  1. Choudhary B,.et al. Effect of Ashwagandha in improving cardiorespiratory endurance in healthy athletic adults. Ayurvedic, 2015 Jan-Mar, 36(1).
  2. Wankhede s. et al. Examining the effect of Withania somnifera supplementation on muscle strength and recovery. A randomized controlled Trial. Journal of Soc Sports Nutrition.  2015 Nov 12:43.
  3. Shenoy S. et. al. Effects of eight-week supplementation of Ashwagandha on cardiorespiratory endurance in elite Indian cyclists. Journal of Ayurvedic Integrated 2012.
  4. Sandhu JS, et. al. Effects of Withania somnifera (Ashwagandha) and Terminalia arjuna (Arjuna) on physical performance and cardiorespiratory endurance in healthy young adults. International Journal of Ayurveda Research. 2010 July 1 (3).
  5. Durg S. et. al. Withania somnifera in male infertility: An evidence-based systematic review and meta-analysis. Phytomedicine 2018 Nov 50:247-256.
  6.  Gupta A, et. al. Efficacy of Withania somnifera on seminal plasma metabolites of infertile males: a proton NMR study at 800 MHz. Journal of Ethnopharmacology. 2013 Aug 26;149 (1).
  7.  Ahmad MK et. al. Withania somnifera improves semen quality by regulating reproductive hormone levels and oxidative stress in seminal plasma of infertile males. Fertility and Sterility Journal. 2010 Aug 94 (3).
  8.  Dar NJ. Et. al. Pharmacologic overview of Withania somnifera. Cell Mol Life Science. 2015 Dec; 72 (23).
  9.  K Chandrasekhar et al. A Prospective, Randomized Double-Blind, Placebo-Controlled Study of Safety and Efficacy of a High-Concentration Full-Spectrum Extract of Ashwagandha Root in Reducing Stress and Anxiety in Adults. Indian Journal of Psychol and Medicine. 2012 Jul-Sep; 34(3).