Ashwagandha and Cortisol: What the 2012 Chandrasekhar Study Actually Found

The Study Everyone Cites But Almost Nobody Has Actually Read

If you spend any time in wellness spaces — whether that’s Reddit threads about burnout, podcast episodes on biohacking, or the supplement aisle at your local health store — you’ve probably heard some version of the same claim: “Ashwagandha lowers cortisol. Science confirms it.” And the citation attached to that claim, more often than not, is a 2012 paper by Chandrasekhar, Kapoor, and Anishetty.

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Here’s the thing: the study is real, the findings are legitimate, and they’re actually quite interesting. But the way that research gets compressed and reshared has stripped out almost everything that made the original findings meaningful — and added a few things the researchers never actually said. As someone who teaches scientific literacy and has ADHD (which means I’ve had a very personal relationship with stress hormones and the supplements people suggest for managing them), I find this particular gap between evidence and popular interpretation worth unpacking carefully. [2]

So let’s go through what Chandrasekhar et al. (2012) actually did, what they actually measured, what they actually found, and what all of that reasonably means for knowledge workers trying to make smart decisions about stress management.

What the Researchers Actually Set Out to Do

The full title of the paper is “A Prospective, Randomized Double-Blind, Placebo-Controlled Study of Safety and Efficacy of a High-Concentration Full-Spectrum Extract of Ashwagandha Root in Reducing Stress and Anxiety in Adults.” That title is already doing a lot of work that most summaries ignore. Notice it says full-spectrum extract and specifies a high-concentration formulation. This isn’t just dried ashwagandha root powder sold in a grocery store bin — it’s a standardized extract called KSM-66, produced under specific conditions to concentrate the withanolide compounds believed to be pharmacologically active.

The study was conducted in India and recruited 64 adults between the ages of 18 and 54 who self-reported experiencing chronic stress. Participants were randomly assigned to receive either 300 mg of the KSM-66 ashwagandha extract twice daily (600 mg total per day) or a visually identical placebo, for a period of 60 days. Importantly, the study used a double-blind design, meaning neither the participants nor the researchers administering the study knew who was getting the real supplement (Chandrasekhar et al., 2012).

They measured outcomes across several dimensions: self-reported stress and anxiety via validated psychological scales, general wellbeing, and — here’s the part everyone quotes — serum cortisol levels drawn from blood samples at baseline and at the end of the 60-day period.

The Cortisol Numbers: What They Found and What They Mean

The headline finding that circulates online is roughly this: ashwagandha reduced cortisol by 28%. That number is real. The ashwagandha group showed a statistically significant reduction in serum cortisol compared to the placebo group, and the percentage reduction was approximately 27.9% (Chandrasekhar et al., 2012). The placebo group, by contrast, showed a much smaller reduction — around 7.9% — which is itself interesting and speaks to the power of expectation and general study participation effects.

But here’s where the nuance lives, and where most popular summaries go quiet. The blood cortisol measurements were taken at a single point in time — a morning blood draw — rather than through something like a 24-hour urinary cortisol test or multiple diurnal measurements tracking how cortisol fluctuates throughout the day. Cortisol has a pronounced daily rhythm: it peaks sharply in the first 30–45 minutes after waking (the cortisol awakening response), then declines across the day. A single morning measurement captures one moment in that pattern, not the full picture of someone’s cortisol physiology.

This doesn’t mean the finding is wrong or unimportant. A meaningful reduction in morning serum cortisol in chronically stressed adults is genuinely significant. But it does mean we should be careful about interpreting it as “ashwagandha normalizes your entire cortisol system” when what was demonstrated is more specifically a reduction in a point-in-time measure among a particular population using a particular extract at a particular dose. [1]

The Psychological Outcomes Were Actually the Stronger Story

Interestingly, if you read the full paper rather than just the abstract, the cortisol data is almost secondary to the psychological measures — which showed even more striking effects. The study used the Perceived Stress Scale (PSS), which is a well-validated self-report tool asking people how often in the past month they’ve felt overwhelmed, unable to control important things in their life, or nervous and stressed. The ashwagandha group showed a 44% reduction in PSS scores compared to 5.5% in the placebo group (Chandrasekhar et al., 2012). [4]

They also used the General Health Questionnaire-28 (GHQ-28) and the Depression Anxiety Stress Scale (DASS), both of which showed similarly large improvements in the ashwagandha group. Sleep quality, which was assessed through a subscale measure, also improved significantly. For knowledge workers — people whose jobs demand sustained cognitive performance, and for whom perceived stress is often as impairing as any objective physiological measure — these psychological outcomes arguably matter more than the cortisol number in day-to-day functional terms. [5]

The relationship between perceived stress and objective cortisol levels is real but messier than most wellness content implies. People can have high perceived stress with normal cortisol, and vice versa. What the Chandrasekhar study suggests is that this particular ashwagandha extract appeared to move both measures in the same direction, which is actually a relatively rare and meaningful convergence in this kind of research.

Study Limitations You Should Actually Know About

I want to be direct here, because I think respecting the evidence means respecting its boundaries. The Chandrasekhar (2012) study has several limitations that matter if you’re trying to make a rational personal decision.

• Sample size: 64 participants is small. Statistical significance with n=64 is achievable, but effect size estimates can be unstable. The findings need replication in larger samples before we treat them as settled.
• Duration: 60 days tells us something about short-term effects but nothing about long-term use, potential tolerance effects, or what happens when someone stops taking the supplement.
• Population specificity: The participants were Indian adults aged 18–54 with self-reported chronic stress. Generalizability to different populations, age groups, or stress profiles isn’t guaranteed.
• Funding and extract specificity: The study used KSM-66, a proprietary extract. This doesn’t invalidate the findings, but it does mean results may not transfer to other ashwagandha products with different extraction methods, different concentrations of active compounds, or different delivery forms.
• Cortisol measurement methodology: As noted, a single time-point serum measure gives a limited window into cortisol dynamics.

None of these limitations mean you should dismiss the study. They mean you should hold the findings with appropriate confidence — interested, moderately convinced, but not treating a single 64-person trial as the final word on a complex endocrine and neurological question.

How This Fits Into the Broader Research Landscape

The 2012 Chandrasekhar paper didn’t appear in a vacuum, and it hasn’t stood alone since. Ashwagandha has been studied in various forms for anxiety, stress, athletic performance, testosterone, and cognitive function. A systematic review and meta-analysis by Pratte et al. (2014) examined several human trials of ashwagandha and concluded that the evidence for stress and anxiety reduction was promising but called for more rigorous large-scale trials. More recently, a study by Salve et al. (2019) used a similar 60-day protocol with KSM-66 and found comparable reductions in perceived stress and cortisol, lending some replication credibility to the Chandrasekhar findings. [3]

What’s emerging across this literature is a relatively consistent signal: standardized ashwagandha extracts at doses in the 300–600 mg per day range appear to reduce self-reported stress and anxiety in adults experiencing chronic stress, with accompanying (though less consistently measured) reductions in cortisol markers. The mechanism most often proposed involves withanolides — the steroidal lactone compounds in ashwagandha — potentially modulating the hypothalamic-pituitary-adrenal (HPA) axis, which is the central regulatory system governing cortisol release (Singh et al., 2011).

The HPA axis explanation is plausible and aligns with ashwagandha’s traditional classification as an adaptogen — a substance thought to help the body resist physiological and psychological stress — but direct mechanistic evidence in humans remains limited. Most of the mechanistic work has been done in animal models, which don’t always translate cleanly to human physiology.

What This Actually Means If You’re a Chronically Stressed Knowledge Worker

Let’s get practical, because evidence without application is just trivia. If you’re in your late twenties to mid-forties, working in a demanding cognitive role, and you’re experiencing what feels like sustained background stress — the kind that makes it hard to focus, disrupts sleep, and leaves you feeling perpetually behind — you might reasonably be wondering whether ashwagandha is worth trying.

Based on the Chandrasekhar study and the broader literature, here’s what I’d actually tell a colleague: the evidence is real enough to take seriously, but specific enough that the details matter considerably.

• Extract type matters: KSM-66 and Sensoril are the two most studied standardized extracts. If you’re going to trial ashwagandha, using a product that specifies one of these (or provides standardized withanolide content) gives you the best chance of replicating what was studied.
• Dose matters: The Chandrasekhar study used 300 mg twice daily. Many products contain 200–250 mg per capsule. Matching the studied dose as closely as possible is rational if you’re treating this as a personal experiment.
• Timeline matters: The study ran for 60 days. Expecting to notice effects in a week is setting yourself up for premature conclusions in either direction.
• Context matters enormously: Ashwagandha is not a substitute for addressing the sources of chronic stress. If your cortisol is elevated because you’re sleeping five hours a night, working without adequate breaks, and have no recovery practices, a supplement is unlikely to compensate meaningfully. The study participants were stressed but were otherwise living their lives — they weren’t in crisis states requiring structural intervention.

For me personally, having ADHD means my nervous system tends to run hot in certain ways — the overlap between stress dysregulation and attention difficulties is real and documented. I’ve approached ashwagandha with exactly the cautious curiosity I’m describing here: interested in the signal, aware of the noise, and not expecting it to do anything my sleep and exercise habits haven’t already been asked to do first.

The Larger Problem With How We Cite Science

There’s a pattern worth naming, because it extends well beyond ashwagandha. A single well-designed small study produces a finding. That finding gets picked up and simplified in a press release or a science journalist’s summary. The summary drops the caveats, emphasizes the most dramatic number, and becomes the thing everyone shares. Eventually the number — 28% cortisol reduction! — separates entirely from its context and floats around the internet as established fact.

This isn’t unique to supplement research. It happens with nutrition studies, cognitive science, exercise research, and pharmaceutical trials. The problem is that the simplified version doesn’t give you what you need to make a good personal decision. You need the sample size. You need to know what was actually measured and how. You need the comparison condition. You need the confidence intervals, not just the p-value. And you need to know who funded it and whether the specific product studied is the one being sold to you.

The Chandrasekhar et al. (2012) study is, by the standards of nutritional supplement research, a reasonably well-designed trial. It used validated outcome measures, a double-blind design, and produced findings consistent across multiple outcome types. It deserves to be cited. It just deserves to be cited accurately — as a promising 60-day, 64-person, single-extract study, not as definitive proof that ashwagandha rewires your stress response.

Reading the actual study — which is accessible through PubMed — takes about 20 minutes. Those 20 minutes will give you a clearer, more honest picture of what the science says than most of the content produced about it, and that clarity is worth considerably more than any supplement.

Last updated: 2026-03-28

References

• Chandrasekhar, K., Kapoor, J., & Anishetty, S. (2012). A prospective, randomized double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha root in reducing stress and anxiety in adults. Indian Journal of Psychological Medicine. Link
• Jamnekar, P. P. et al. (2025). Ashwagandha as an Adaptogenic Herb: A Comprehensive Review of Contemporary Evidence. PMC. Link
• Thanawala, S. et al. (2026). Efficacy and safety of Ashwagandha root extract sustained-release formulation in reducing stress: A randomized, double-blind, placebo-controlled study. PMC. Link
• Smith, S. J. et al. (2023). Exploring the efficacy and safety of a novel standardized ashwagandha root extract. Journal of Psychopharmacology. Link
• Moriarty, J. et al. (2024). Safety of 12‐Months Administration of Ashwagandha (Withania somnifera) Root Extract. Phytotherapy Research. Link
• American Botanical Council. (n.d.). Withania somnifera: Clinical Trials. HerbMedPro. Link

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