Ashwagandha

Moderate Evidence
Last reviewed July 2026

An Ayurvedic adaptogen with solid clinical evidence for stress, cortisol and testosterone support.

Overview

Ashwagandha (Withania somnifera) is an adaptogenic herb that has been central to Ayurvedic medicine for over 3,000 years. Modern research has validated several of its traditional uses, particularly around stress and anxiety reduction. The active compounds, withanolides, appear to modulate the stress response by influencing cortisol levels and the HPA axis. Multiple double-blind, placebo-controlled trials in healthy stressed adults have demonstrated clinically meaningful reductions in perceived stress, cortisol and anxiety scores.

Evidence rating

Moderate Evidence

Multiple randomised controlled trials support ashwagandha's ability to reduce cortisol and perceived stress. Evidence for testosterone support and athletic performance is moderate. Sleep improvement evidence is early but encouraging. The KSM-66 and Sensoril extracts are the most studied forms.

Common uses

  • Moderate Evidence
    Reducing perceived stress and anxiety
  • Moderate Evidence
    Lowering cortisol levels
  • Moderate Evidence
    Supporting testosterone and male hormone balance
  • Moderate Evidence
    Athletic performance and muscle recovery
  • Early Evidence
    Improving sleep quality

Safety & cautions

Worth checking with a pharmacist if you take medication.

Common forms

KSM-66 ExtractBest form

The most extensively studied standardised root extract. Used in the majority of positive clinical trials.

Sensoril Extract

Root and leaf extract. Also well-studied, particularly for stress and anxiety.

Raw Powder (whole root)

Potency varies significantly. Much less reliable than standardised extracts.