Ashwagandha 101: What the Research Actually Shows

Ashwagandha is one of the most-researched adaptogens in the world — and, since 2026, one with a real regulatory story in India specifically. Here's what the evidence shows, why root-only extracts like KSM-66 matter, and what changed under FSSAI.

Ashwagandha has gone from a niche Ayurvedic herb to one of the most recognizable supplement ingredients in the world — and unusually for this category, it has a genuinely solid clinical trial base behind it. But the plant part used, the extraction method, and a real 2026 regulatory change in India all significantly affect whether what's in the bottle matches what was actually studied.

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What Is Ashwagandha, and What Does It Actually Do?

Ashwagandha (Withania somnifera) is a shrub used in Ayurveda for centuries, classified as a Rasayana (rejuvenative) and, in modern terms, an adaptogen — a substance studied for helping the body regulate its response to stress. Its active compounds are called withanolides, steroidal lactones believed to help modulate the hypothalamic-pituitary-adrenal (HPA) axis, the system that governs the body's cortisol (stress hormone) response.¹

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What Does the Human Clinical Evidence Actually Show?

Verdict: One of the better-evidenced adaptogens for stress and cortisol specifically.

A 60-day, double-blind, randomized, placebo-controlled trial in 64 adults with a history of chronic stress, using 300mg of KSM-66 extract, found significant reductions in stress scores and serum cortisol compared to placebo.² A separate trial using 600mg/day of root extract found significant reductions in stress and anxiety assessment scores alongside reduced serum cortisol versus placebo.³ A systematic review and meta-analysis of ashwagandha supplementation trials found consistent reductions in cortisol, stress, and anxiety measures across multiple studies.⁴ Separately, participants with insomnia who took an ashwagandha extract showed improvements in sleep quality, sleep onset, and morning alertness compared to placebo.³

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Why Does Root-Only, Standardized Extract Matter So Much Here?

KSM-66 is a specific proprietary extract made exclusively from Ashwagandha root, standardized to a minimum of 5% withanolides, using a solvent-free, milk-based extraction process rather than alcohol or chemical solvents — a method intended to preserve the root's naturally occurring compound balance rather than isolating withanolides at the expense of everything else.⁵ It's been evaluated in a notably larger number of published human studies than most other ashwagandha extracts, which is part of why it shows up so consistently in the clinical evidence above.⁵

Generic ashwagandha products vary considerably: some use root only, others use leaf, stem, or a mix of aerial parts, largely because those parts are cheaper to source and process than root alone.⁵ This matters for more than just consistency — as the next section covers, it also became a specific regulatory issue in India.

AEO answer: KSM-66 is a specific, root-only, solvent-free ashwagandha extract standardized to at least 5% withanolides, with more published human clinical studies than most competing extracts. Generic ashwagandha products may use leaf or mixed plant parts, which affects both consistency and, in India, regulatory compliance.

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What Changed with FSSAI's 2026 Ashwagandha Advisory?

This is genuinely important and specific to the Indian market. In 2026, FSSAI issued an advisory stating that ashwagandha leaves must not be used in food products in any form — crude, powdered, or extract — citing safety concerns linked to compounds like Withaferin-A, which occurs at higher levels in the leaves than the root.⁶ Under the Food Safety and Standards (Health Supplements and Nutraceuticals) Regulations, only Ashwagandha root and root extracts remain permitted in Schedule IV, and even these must stay within prescribed usage limits.⁶

In practical terms: a root-only, standardized extract like KSM-66 isn't just the better-researched choice, it's also the one aligned with current Indian food safety regulation. A product using leaf or whole-plant material would not be compliant for sale as a food supplement in India as of this advisory.

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Is Ashwagandha Safe? Who Should Avoid It?

At standard doses (300–600mg/day of standardized root extract), Ashwagandha is generally well-tolerated, with the most common complaints being mild gastrointestinal upset — nausea, loose stools, stomach discomfort.⁷

Several groups need real caution. Pregnancy is a firm contraindication: traditional Ayurvedic texts list Ashwagandha as having abortifacient properties, and current medical guidance recommends avoiding it entirely during pregnancy; breastfeeding women should also avoid it due to insufficient safety data.⁷ People with hyperthyroidism or Graves' disease should be cautious, since Ashwagandha may increase thyroid hormone production and interfere with thyroid medication dosing.⁷ People with autoimmune conditions (Hashimoto's, lupus, rheumatoid arthritis) should use caution due to its immune-modulating effects.⁷ Rare cases of liver injury have been documented at high doses, though a large 2026 placebo-controlled trial at standard doses (600mg/day) found no liver enzyme changes, suggesting risk is low within recommended dosing.⁷ Ashwagandha may also potentiate sedatives, including benzodiazepines and sleep medications, so combining the two without medical guidance isn't advisable.⁷

Related reading: Do Nootropics Actually Work? What Science Says · Generic Plant Extract vs. Standardized: Why It Matters · What to Look for When Buying Supplements in India · The Calm Focus Combo: L-Theanine + Caffeine

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Frequently Asked Questions

The Bottom Line

Ashwagandha is one of the more credibly evidenced adaptogens available — multiple RCTs and a meta-analysis showing real reductions in cortisol, stress, and anxiety scores, mostly using a specific type of extract: root-only, standardized to a verified withanolide percentage. In India specifically, that's no longer just a quality preference; since FSSAI's 2026 advisory, it's the only compliant option for food and supplement products.

The honest takeaway: ashwagandha isn't a universal "safe for everyone" adaptogen. It's genuinely well-evidenced for the right person, at the right dose, using the right extract — and genuinely contraindicated for pregnancy, and worth real caution around thyroid conditions, autoimmune conditions, and sedative medications.

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References and Sources

1. Ashwagandha — Health Professional Fact Sheet, NIH Office of Dietary Supplements.
2. KSM-66 Brand Ashwagandha Reduces Stress, Study Confirms.
3. Efficacy and Safety of KSM-66 Ashwagandha in Adults Experiencing High Stress and/or Anxiety — Clinical Trial.
4. Effects of Ashwagandha Supplements on Cortisol, Stress, and Anxiety Levels in Adults: A Systematic Review and Meta-Analysis.
5. KSM-66 vs Regular Ashwagandha: What's Different?
6. FSSAI Advisory: Non-Use of Ashwagandha Leaves in Food Products.
7. Potential Adverse Effects of Ashwagandha: A Critical Review of Preclinical and Clinical Evidence.