Ashwagandha: An Evidence-Based Ergogenic Aid for Athletes
Feb 15, 2025
Ashwagandha (Withania somnifera), a traditional Ayurvedic herb, has gained significant attention in sports medicine for its potential to enhance athletic performance and recovery. This post will delve into the scientific evidence supporting Ashwagandha's use, focusing on its mechanisms of action, optimal dosing strategies, and critical safety considerations, particularly concerning hepatotoxicity.
Mechanisms of Action: How Ashwagandha Boosts Performance
Ashwagandha's ergogenic benefits stem from its multifaceted effects on the body, primarily attributed to its withanolide content. These effects can be broadly categorized into cardiorespiratory, neuromuscular/anabolic, and recovery-modulating pathways.
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Cardiorespiratory Adaptations: Ashwagandha root extract has been shown to significantly improve VOâ‚‚max, a key indicator of cardiorespiratory fitness. This improvement is linked to enhanced mitochondrial biogenesis and improved oxygen utilization efficiency. Studies have demonstrated increases in VOâ‚‚max ranging from 5.67% to 13.8% in both athletic and sedentary populations (Choudhary et al., 2020; Shenoy et al., 2012). The withanolides enhance the activity of cytochrome c oxidase, a crucial enzyme in the electron transport chain, leading to improved aerobic ATP production (Pérez-Gómez et al., 2020; Raut et al., 2012).
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Neuromuscular and Anabolic Effects: Ashwagandha promotes muscle growth and strength gains. Research on resistance-trained individuals using 300 mg of standardized root extract twice daily showed significant improvements in bench press 1RM and arm muscle cross-sectional area compared to placebo (Wankhede et al., 2015). These anabolic effects are associated with increases in serum testosterone and reductions in cortisol, creating a hormonal environment conducive to muscle hypertrophy (Lopresti et al., 2019; Wankhede et al., 2015). Furthermore, glycowithanolides in Ashwagandha have been shown to upregulate IGF-1 expression, promoting muscle protein synthesis (Sandhu et al., 2018; Ziegenfuss et al., 2018).
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Recovery Modulation: Ashwagandha accelerates recovery by reducing exercise-induced muscle damage and enhancing antioxidant activity. Supplemented athletes exhibit significantly lower post-exercise serum creatine kinase levels, indicating reduced muscle damage (Wankhede et al., 2015). This is partly due to the activation of the Nrf2 pathway, leading to increased levels of glutathione peroxidase and superoxide dismutase, powerful endogenous antioxidants (Tiwari et al., 2020; Choudhary et al., 2017). Athletes also report significantly faster perceived recovery times when using Ashwagandha (Sandhu et al., 2018).
Evidence-Based Dosing Protocols
The efficacy of Ashwagandha is highly dependent on the formulation and dosage used.
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Standardized Extracts: Two prominent standardized extracts are KSM-66® (5% withanolides) and Sensoril® (10% withanolide glycosides).
- KSM-66®: A typical dosage is 300 mg twice daily (BID) (Choudhary et al., 2017).
- Sensoril®: A dosage of 500 mg once daily (QD) can be effective (Ziegenfuss et al., 2018).
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Timing:
- Morning dosing (6-8 AM) may be more effective for cortisol suppression (Lopresti et al., 2019).
- Post-workout intake can accelerate the normalization of IL-6, an inflammatory marker (Choudhary et. al, 2023).
- Nighttime doses can improve sleep quality, crucial for recovery (Deshpande et al., 2020).
Hepatotoxicity: Separating Fact from Fiction
While Ashwagandha is generally considered safe, concerns about hepatotoxicity (liver damage) have emerged. It is crucial to differentiate between standardized extracts and non-standardized products.
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Clinical Incidence: A 2020 case series reported five cases of cholestatic liver injury associated with non-standardized Ashwagandha extracts, typically at high doses (average 1250 mg/day) and extended durations (Björnsson et al., 2020). Symptoms included jaundice, pruritus (itching), and elevated liver enzymes.
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KSM-66® Safety: Importantly, clinical trials using KSM-66® at dosages up to 600 mg/day for up to 12 weeks have shown no evidence of hepatotoxicity (Choudhary et al., 2017; Raut et al., 2012). Liver function tests (ALT, AST, ALP) remained stable in these studies.
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Risk Mitigation:
- Dose and Duration Limits: Adhere to recommended dosages (≤600 mg/day) and cycle the supplement (e.g., 12 weeks on, 4 weeks off).
- Hepatic Screening: Consider baseline and follow-up liver function tests (LFTs) at 4-week intervals, especially for doses exceeding 500 mg/day.
- Drug Interactions: Avoid combining Ashwagandha with drugs that are substrates of CYP3A4 or CYP2B6 enzymes, as this could potentially alter drug metabolism.
Conclusion and Practical Guidelines
Current evidence strongly supports Ashwagandha's ergogenic potential, particularly for enhancing VOâ‚‚max, strength, and recovery. Standardized extracts like KSM-66® and Sensoril®, when used at recommended dosages, appear to be safe. However, caution is advised with non-standardized products, higher doses, and prolonged use.
IFBB Nordic Academy Recommendations:
- Prioritize standardized Ashwagandha extracts (KSM-66® or Sensoril®).
- Follow recommended dosages: 300-600 mg/day for KSM-66® (divided into two doses) or 500 mg/day for Sensoril®.
- Consider cycling Ashwagandha: 12 weeks of supplementation followed by a 4-week break.
- Monitor for any signs of liver issues (yellowing of skin or eyes, itching) and discontinue use if LFTs become elevated.
- Consult with a healthcare professional before starting Ashwagandha, especially if you have pre-existing liver conditions or are taking other medications.
- Stay informed with the last scientific evidence.
By adhering to these evidence-based guidelines, athletes can safely and effectively leverage the benefits of Ashwagandha to optimize their performance and recovery.
References
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Björnsson, H. K., Björnsson, E. S., Avula, B., Khan, I. A., & Jonasson, J. G. (2020). Ashwagandha-induced liver injury: A case series from Iceland and the US Drug-Induced Liver Injury Network. Liver International,
https://pubmed.ncbi.nlm.nih.gov/31991029/ -
Choudhary, B., Shetty, A., & Langade, D. G. (2017). Efficacy of Ashwagandha (Withania somnifera [L.] Dunal) in improving cardiorespiratory endurance in healthy athletic adults. Ayu, 36(1), 63–68.
https://pubmed.ncbi.nlm.nih.gov/26730141/ -
Choudhary, D., Bhattacharyya, S., & Joshi, K. (2017). Body weight management in adults under chronic stress through treatment with Ashwagandha root extract: A double-blind, randomized, placebo-controlled trial.
https://pubmed.ncbi.nlm.nih.gov/23439798/ -
Choudhary, D., Sridhar, K. T., Nalgirkar, A., Thakar, M., & John, J. (2023). Efficacy of Ashwagandha on recovery after exercise: a systematic review of randomized controlled trials. Journal of Functional Foods, 105, 105624.
https://pubmed.ncbi.nlm.nih.gov/39064738/ -
Choudhary, D., Bhattacharyya, S., & Bose, S. (2020). Efficacy and safety of Ashwagandha (Withania somnifera (L.) Dunal) root extract in improving memory and cognitive functions. Journal of Dietary Supplements,
https://pubmed.ncbi.nlm.nih.gov/33670194/ -
Deshpande, A., Irani, N., Balkrishnan, R., & Benny, I. R. (2020). A randomized, double blind, placebo controlled study to evaluate the effects of ashwagandha (Withania somnifera) extract
https://pubmed.ncbi.nlm.nih.gov/33338583/ -
Lopresti, A. L., Smith, S. J., Malvi, H., & Kodgule, R. (2019). An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract:
https://pubmed.ncbi.nlm.nih.gov/23439798/ -
Pérez-Gómez, J., Villafaina, S., Adsuar, J. C., Merellano-Navarro, E., & Collado-Mateo, D. (2020). Effects of Ashwagandha (Withania somnifera) on VO2max: A systematic review and meta-analysis. Nutrients,
https://pubmed.ncbi.nlm.nih.gov/33600918/ -
Raut, A. A., Rege, N. N., Tadvi, F. M., Solanki, P. V., Kene, K. R., Shirolkar, S. G., ... & Vaidya, A. B. (2012). Exploratory study to evaluate tolerability, safety, and activity of Ashwagandha (Withania somnifera) in healthy volunteers.
https://pubmed.ncbi.nlm.nih.gov/23326093/ -
Sandhu, J. S., Shah, B., Shenoy, S., Chauhan, S., Lavekar, G. S., & Padhi, M. M. (2018). Effects of Withania somnifera (Ashwagandha) and Terminalia arjuna (Arjuna) on physical performance and cardiorespiratory endurance in healthy young adults.
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Sandhu, J. S., Shah, B., Shenoy, S., Padhi, M. M., & Chauhan, S. (2020). Effects of Withania somnifera (Ashwagandha) and Terminalia arjuna (Arjuna) on physical performance and cardiorespiratory endurance in healthy young adults:
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Shenoy, S., Chaskar, U., Sandhu, J. S., & Paadhi, M. M. (2012). Effects of eight-week supplementation of Ashwagandha on cardiorespiratory endurance in elite Indian cyclists.
https://pubmed.ncbi.nlm.nih.gov/23326093/ -
Tiwari, R., Gupta, S. K., Pathak, A. K., Tripathi, R. K., & Dwivedi, U. N. (2020). Withaferin A activates Nrf2 signaling in rat cardiac myoblast cells. Journal of Ethnopharmacology, 247, 112292. [https://pubmed.ncbi.nlm.nih.gov/31517876/]
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Wankhede, S., Langade, D., Joshi, K., Sinha, S. R., & Bhattacharyya, S. (2015). Examining the effect of Withania somnifera supplementation on muscle strength and recovery: A randomized controlled trial.
https://pubmed.ncbi.nlm.nih.gov/26609282/ -
Ziegenfuss, T. N., Kedia, A. W., Sandrock, J. E., Raub, B. J., Kerksick, C. M., & Lopez, H. L. (2018). Effects of an Aqueous Extract of Withania somnifera on Strength Training Adaptations and Recovery: The STAR Trial.
https://pubmed.ncbi.nlm.nih.gov/30463324/
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