Efficacy and safety of sustained release ashwagandha root extract capsules on muscle strength and cardiorespiratory endurance in recreationally active individuals: A randomized, double-blind, placebo-controlled trial

Abstract Introduction Previous studies suggest that conventional Ashwagandha ( Withania somnifera ) root extracts may improve physical performance in both athletic and non-athletic populations. However, evidence on sustained-release ashwagandha formulations is lacking. This randomized double-blind, placebo-controlled trial evaluated the safety and efficacy of sustained-release ashwagandha root extract (AshwaSR) 300 mg in improving muscle strength in recreationally active healthy individuals. Methods Eligible participants aged 25-50 years received AshwaSR 300 mg or placebo capsules once daily for 90 days. Changes in one-repetition maximum (1-RM) bench press, maximal oxygen uptake (VO 2 max), serum testosterone, creatine kinase (CK) and lactate dehydrogenase (LDH) concentrations, and quality of life (QoL using SF-12 questionnaire) from baseline till study end were evaluated. Results Of 84 enrolled participants, 83 completed the study (AshwaSR, n=41; Placebo, n=42). Compared with placebo, participants receiving AshwaSR demonstrated significantly greater improvements in muscle strength and cardiorespiratory endurance starting from day 30 (1-RM: 4.69 vs 2.23 kg; VO 2 max: 9.99 vs 6.64 mL/kg/min; p