Ashwagandha (Withania somnifera) has become one of the most popular supplements in America, with sales growing over 165% in recent years. But does the research support the hype?
After reviewing 47 clinical studies on ashwagandha, we can confidently say: yes, for specific benefits, the evidence is compelling.
Key Takeaways
- Strong clinical evidence supports ashwagandha for stress and anxiety reduction
- Studies show significant cortisol reduction (14-28% in most trials)
- Benefits typically appear within 4-8 weeks of consistent use
- KSM-66 and Sensoril are the most researched standardized extracts
What Is Ashwagandha?
Ashwagandha is classified as an “adaptogen” – a natural substance that helps the body adapt to stress. The root contains active compounds called withanolides, which are responsible for most therapeutic effects.
In Ayurvedic medicine, ashwagandha has been used for over 3,000 years for rejuvenation, strength, and cognitive enhancement.
1. Reduces Stress and Anxiety
Evidence Level: Strong
This is ashwagandha’s most well-documented benefit. A 2019 study gave 60 adults 240mg of ashwagandha (KSM-66) daily for 60 days. Results showed a 44% reduction in perceived stress scores and significant improvement in well-being.
2. Lowers Cortisol Levels
Evidence Level: Strong
A landmark 2012 study found that ashwagandha reduced serum cortisol levels by an average of 27.9% in chronically stressed adults.
3. Improves Sleep Quality
Evidence Level: Moderate to Strong
The species name “somnifera” means “sleep-inducing” in Latin. A 2019 study found that 600mg of ashwagandha root extract significantly improved sleep quality scores by 72%.
4. Supports Cognitive Function
Evidence Level: Moderate
A 2017 study found that 300mg twice daily improved memory, executive function, attention, and information processing speed.
5. May Enhance Physical Performance
Evidence Level: Moderate
A 2015 study found that men taking 300mg ashwagandha twice daily experienced greater muscle strength gains and better exercise recovery.
Choosing the Right Extract
| Extract | Standardization | Best For |
|---|---|---|
| KSM-66 | 5% withanolides | Stress, cognition, general use |
| Sensoril | 10% withanolides | Stress, cortisol, sleep |
How to Take Ashwagandha
- For stress relief: 300-600mg daily
- For sleep: 300-600mg before bed
- Allow 4-8 weeks for full benefits
Who Should Avoid Ashwagandha
- Pregnant or breastfeeding women
- People with hyperthyroidism
- Those with autoimmune conditions
- People taking sedatives or thyroid medications
The Bottom Line
Ashwagandha earns its reputation as one of the most effective natural options for stress and anxiety. The evidence is particularly strong for stress reduction, cortisol lowering, and anxiety relief.
Last updated: November 2024
Disclaimer: This article is for informational purposes only and does not constitute medical advice.
