Ashwagandha has been a popular supplement for years, praised for its potential to do everything from reduce stress to boost performance. But with so many claims, it can be hard to know what's real. According to Dr. Mike Israetel, a comprehensive new narrative review published in February 2025 gives us the clearest picture yet of what this ancient herb can—and can't—do for your physique and performance goals.
The study, published in the Journal of Nutrition and Metabolism, consolidates decades of research to explore ashwagandha's mechanisms, health benefits, and role in sport. The findings suggest it’s not a miracle supplement, but it is a useful tool with a variety of moderate, real-world benefits.
TL;DR: The 2025 Verdict on Ashwagandha
- A new review paper describes ashwagandha as a "moderate, multi-mechanism adjunct" supplement.
- It provides mild-to-moderate benefits for muscle gain (estimated at 25-40% of creatine's effect) and a more notable boost for strength (40-60% of creatine's effect).
- Its primary effects likely stem from a substantial reduction in the stress hormone cortisol and a small but detectable boost in testosterone.
- It has also been shown to reliably improve VO2 max (aerobic fitness) and enhance perceived recovery from training.
- It should be viewed as a tool for stress management and gaining a slight performance edge, not as a primary driver of muscle growth.
The Performance Benefits: A Closer Look
The review analyzed multiple studies to determine ashwagandha's effect on key performance metrics, typically using a dose of 300-600mg per day over 8-12 weeks.
Muscle and Strength Gains
For those looking to get bigger and stronger, the results are promising, but modest. The review found a discernible increase in lean mass, roughly 25-40% of the effect you might expect from a proven supplement like creatine. The impact on max strength was more significant, with studies showing a 5-8% increase in one-rep maxes—an effect estimated to be 40-60% as powerful as creatine.
Endurance and Recovery
One of the most impressive findings was ashwagandha's effect on aerobic fitness. Multiple studies have shown it provides a meaningful boost to VO2 max, which can improve your ability to recover between hard, high-rep sets. This is complemented by data showing a decrease in perceived soreness and a 10-20% improvement in perceived recovery after training.
The Core Mechanism: Better Hormones, Less Stress
So, how does ashwagandha accomplish all this? The review points to its powerful effects on the endocrine system. The most robust findings show that ashwagandha supplementation leads to:
- A substantial dampening of cortisol.
- A small but notable bump in testosterone.
As Dr. Mike explains, cortisol is in many ways the "anti-testosterone." By lowering the body's primary stress hormone and slightly increasing its primary anabolic hormone, ashwagandha creates a more favorable internal environment for recovery, performance, and muscle growth. This hormonal shift is likely the key driver behind many of its other benefits, from reduced anxiety to better gains in the gym.
Important Considerations and Research Limitations
While the findings are exciting, it's important to view them with a scientific perspective. Dr. Mike highlights several limitations in the current body of research noted by the review:
- Short Study Duration: Most studies last only 8-12 weeks, so long-term effects are still unknown.
- Sex Bias: Around 80% of the studies were conducted on men. Its effects on female athletes are largely unstudied and unknown.
- Geographic Clustering: Many of the studies were conducted in India using the same extract suppliers, which raises questions about potential funding bias that need to be addressed by more global research.
Conclusion: A Solid Tool for Your Toolbox
Ashwagandha is not a "game-changing" supplement that will pack on pounds of muscle overnight. However, the latest research confirms that it is a safe and effective tool with multiple moderate benefits. Its real strength lies in its ability to lower cortisol and manage stress, which can have positive downstream effects on performance, recovery, and overall well-being.
For a typical dose of 300-600mg per day, it can be a particularly useful supplement for chronically stressed individuals or for athletes navigating a demanding period, such as the final weeks of a fat loss diet.
