Recommended Dose of Ashwagandha for Anxiety
For anxiety in adults, ashwagandha root extract should be dosed at 300 mg twice daily (600 mg/day total), standardized to contain 2.5% withanolides, which provides approximately 12.5 mg of withanolides per day.
Evidence-Based Dosing
The most robust evidence supports 300 mg twice daily as the optimal dose for anxiety reduction:
High-dose regimen (600 mg/day total): Multiple high-quality randomized controlled trials demonstrate that 300 mg of ashwagandha root extract twice daily, standardized to 2.5% withanolides, significantly reduces anxiety scores on validated scales including the Hamilton Anxiety Rating Scale (HAM-A) and Generalized Anxiety Disorder-7 (GAD-7) 1, 2, 3.
Lower-dose alternative (250 mg/day total): A dose of 125 mg twice daily (250 mg/day total) also shows statistically significant anxiety reduction, though the effect size is smaller compared to the 600 mg/day regimen 3.
Mechanism and Clinical Outcomes
The anxiolytic effects are mediated through multiple pathways:
Cortisol reduction: Both 250 mg/day and 600 mg/day doses significantly reduce morning salivary cortisol levels, with the higher dose showing more pronounced effects (p < 0.0001 vs p < 0.05) 1, 3.
Serotonin enhancement: The 600 mg/day regimen increases urinary and serum serotonin levels, which correlates with improved anxiety and depression scores 1, 2.
Cognitive benefits: The higher dose (600 mg/day) demonstrates significant improvements in multitasking, concentration, and decision-making time on neuropsychological testing 1.
Treatment Duration and Response
Onset of effect: Significant improvements in anxiety scores are typically observed by 30 days, with progressive improvement through 60-90 days of treatment 2, 3.
Optimal duration: Studies demonstrate continued benefit through 8-12 weeks of treatment, suggesting this as a reasonable initial treatment course 1, 2, 3, 4.
Formulation Considerations
Critical formulation details that impact efficacy:
Standardization: Use extracts standardized to 2.5% full-spectrum withanolides according to USP protocol 1, 2.
Bioavailability enhancement: Co-administration with 5 mg of piperine (95% pure) enhances absorption and is included in the most effective studied formulations 1, 2.
Timing: Administer once daily at night or divided into twice-daily dosing 1, 2, 3.
Safety Profile
Ashwagandha demonstrates excellent tolerability across studies:
No serious adverse events were reported in any of the randomized controlled trials at doses up to 600 mg/day 1, 2, 3, 4.
Laboratory parameters (hematological and biochemical) remained within normal ranges throughout treatment periods 1, 2.
Completion rates: Studies show high completion rates (>95%), indicating good tolerability 2, 3.
Clinical Context
While conventional anxiolytics like SSRIs and benzodiazepines remain first-line treatments in clinical guidelines 5, ashwagandha may serve as an alternative for patients seeking herbal options or those who cannot tolerate conventional medications 6. However, patients with severe anxiety, comorbid psychiatric disorders, suicidal ideation, or those who are pregnant should not be treated with ashwagandha without conventional psychiatric evaluation 5.