Dose-Response Effects of Short-Term Ashwagandha Supplementation on Anaerobic and Resistance Exercise Performance in Trained Adults

Background: Ashwagandha (Withania somnifera; ASH) has been proposed as a natural ergogenic aid due to its potential effects on muscular strength, anaerobic capacity, and recovery. Its adaptogenic and antioxidant properties may support resistance exercise performance and reduce exercise-induced fatigue in trained individuals. Methods: Twenty-three resistance-trained adults (9 males, 14 females; age: 22.0 ± 1.95 years; height: 171.0 ± 9.57 cm; body mass: 80.6 ± 21.4 kg) participated in a randomized, double-blind, crossover study examining the dose-response effects of ASH supplementation. Following a familiarization session, participants first completed a control (CON) testing session without supplementation. They then completed low-dose ASH (LDA, 4 mg/kg/day), high-dose ASH (HDA, 14 mg/kg/day), and placebo (PL) conditions for 7 days, separated by 7-day washout periods. Muscular strength, endurance, and anaerobic power were assessed using resistance exercise and Wingate testing. Data were analyzed using two-way repeated-measures ANOVA with Fisher’s LSD post hoc tests (p ≤ 0.05). Results: Bench press (BP) one-repetition maximum (1RM) differed significantly across conditions (p < 0.001), with both ASH doses exceeding CON and PL, and HDA modestly surpassing LDA. Mean ± SD values were CON: 71.1 ± 36.3 kg, PL: 72.1 ± 37.1 kg, LDA: 73.0 ± 37.4 kg, and HDA: 74.1 ± 37.1 kg. BP third-set lifting volume showed a significant treatment effect (p = 0.028), with HDA producing greater volume than PL and LDA. Leg press (LP) 1RM also improved significantly (p < 0.001), with PL, LDA, and HDA exceeding CON and HDA outperforming PL (CON: 311.9 ± 111.8 kg; PL: 321.1 ± 110.0 kg; LDA: 326.6 ± 111.0 kg; HDA: 333.6 ± 109.9 kg). LP third-set lifting volume demonstrated a significant main effect of treatment (p < 0.001), with progressively higher values across conditions. Estimated marginal means were CON: 4374.8 ± 402.0 kg, PL: 4884.4 ± 355.1 kg, LDA: 5437.8 ± 511.1 kg, and HDA: 6216.1 ± 583.1 kg. Post hoc analysis indicated that HDA and LDA were significantly greater than CON, and HDA also exceeded PL. No significant differences were observed for Wingate peak power, mean power, total work, fatigue index, or Tendo-derived peak and average power variables (all p > 0.05). Conclusion: Short-term ashwagandha supplementation improved muscular strength and resistance exercise performance in trained adults, with greater benefits observed at higher doses. These findings support ASH as a potential natural ergogenic aid, although anaerobic power measures were not significantly affected. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.