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#1 in Herbal Supplements Third-Party Tested

KSM-66 Ashwagandha by NutraHerbals

by NutraHerbals

"The most clinically studied ashwagandha extract — KSM-66 root-only formula"

Amazon Rating
4.5/5
Reviews
25,000+
Price Range
$18-24
Servings
60 capsules (30-day supply)
GMP CertifiedNon-GMOGluten-FreeVegan
Our Editorial Rating
9.0
Excellent
FormCapsules
SubcategoryAshwagandha
View on Amazon

Overview

This supplement features KSM-66, the most extensively studied ashwagandha extract in the world with 24+ gold-standard clinical trials. KSM-66 is a full-spectrum root extract standardized to 5% withanolides, produced using a unique extraction process that preserves the natural balance of the root's active compounds. Clinical studies have demonstrated KSM-66's benefits for stress reduction (cortisol lowering), anxiety, sleep quality, testosterone in men, athletic performance, and cognitive function. Each serving provides 600mg of KSM-66 ashwagandha root extract.

Key Ingredients

IngredientAmount
KSM-66 Ashwagandha Root Extract600mg
Withanolides5% (30mg)
BioPerine Black Pepper Extract5mg

Pros & Cons

What We Like

  • KSM-66 — the most clinically studied ashwagandha extract
  • 24+ gold-standard clinical trials published
  • 600mg dose matches clinical study protocols
  • Root-only extract (no leaf, which can cause GI issues)
  • Standardized to 5% withanolides
  • BioPerine included for enhanced absorption
  • Clinically shown to reduce cortisol by 27.9%

What Could Be Better

  • Effects take 4-8 weeks to fully manifest
  • May cause drowsiness in some people
  • Not recommended during pregnancy
  • Can interact with thyroid medications
  • Some people experience GI upset initially
  • Many generic brands claim 'KSM-66' — verify authenticity

Who Is This For?

Best For

  • Stress and anxiety management
  • Cortisol reduction
  • Sleep quality improvement
  • Men wanting testosterone support
  • Athletes seeking recovery benefits

Not Ideal For

  • Pregnant or breastfeeding women
  • Those on thyroid medication (consult doctor)
  • People wanting immediate effects
  • Those with autoimmune conditions (may stimulate immune system)

Our Verdict

9.0/10 — Excellent

If you're going to take ashwagandha, use KSM-66. The clinical evidence is overwhelming — 24+ studies showing benefits for stress, sleep, testosterone, and performance. The 600mg dose in this product matches the protocols used in clinical trials. Just make sure you're getting genuine KSM-66 (look for the logo on the bottle) and give it 4-8 weeks to work.

Alternatives to Consider

No direct alternatives listed for this product yet.