Does Ashwagandha Actually Lower Your Cortisol?
Does Ashwagandha Actually Lower Your Cortisol?
By Jaden Choi — a plain-English look at what the trials actually measured, and why a lower cortisol number doesn't automatically mean a calmer you.
Short answer: yes — of all the claims made for ashwagandha, "it lowers cortisol" is the one with the most consistent trial evidence behind it. Randomized studies have repeatedly shown the herb dropping the body's main stress hormone, in one famous trial by nearly 28% over two months. That part isn't hype.
Here's the twist most articles skip: lowering cortisol and actually feeling less stressed are not the same thing, and the 2025 research is genuinely split on the second half. One new meta-analysis found the cortisol number reliably falls but self-rated stress often doesn't budge; another found both improved. This is a rare case where the "before-and-after lab value" story is cleaner than the "does it change how I feel" story — so let's separate the two honestly.
- The cortisol effect is well supported. A landmark 2012 trial in the Indian Journal of Psychological Medicine found 300 mg of a concentrated root extract twice daily cut serum cortisol by ~27.9% over 60 days, versus 7.9% on placebo.
- But "cortisol down" ≠ "you feel calmer." A 2025 meta-analysis in Nutrition and Health confirmed a significant cortisol drop yet found no significant effect on perceived stress — while a separate 2025 review did find a stress-score benefit. The subjective side is genuinely mixed.
- Most trials are short (6–8 weeks), small, and use one branded extract. There's also a real, if rare, liver-injury signal — ashwagandha is not for people with liver disease, pregnancy, or thyroid conditions without a doctor's sign-off.
First, What "Lowering Cortisol" Even Means
Cortisol is your body's main stress hormone, released by the adrenal glands on a daily rhythm — high in the morning to get you going, tapering off by night. It's not the villain it's marketed as; you need it to wake up, handle stress, and regulate metabolism. The problem is chronically elevated cortisol from ongoing stress, which is loosely linked to poor sleep, belly fat, and feeling wired-but-tired.
Ashwagandha (Withania somnifera) is an herb used in Ayurvedic medicine and marketed as an "adaptogen" — a substance said to help the body resist stress. The specific, testable claim behind that marketing is that it turns down an overactive stress response, and cortisol is the number researchers use to check. So when a study says ashwagandha "lowered cortisol," it means a measured drop in the hormone in the blood or saliva — a physiological signal, not necessarily a mood.
The Studies That Made the Cortisol Claim Famous
The headline finding comes from Chandrasekhar and colleagues (2012), published in the Indian Journal of Psychological Medicine. In this 60-day, double-blind, placebo-controlled trial, 64 adults with a history of chronic stress took either a placebo or 300 mg of a high-concentration full-spectrum root extract (the branded KSM-66) twice a day. The treatment group's serum cortisol fell about 27.9% from baseline, compared with just 7.9% on placebo, alongside a 44% drop on the Perceived Stress Scale. That single number — "ashwagandha lowers cortisol by 28%" — is the one you see quoted everywhere.
A second well-designed trial backs up the hormonal effect. Lopresti and colleagues (2019), in the journal Medicine, gave 60 stressed adults either placebo or 240 mg/day of a standardized extract for 60 days. Relative to placebo, the ashwagandha group showed statistically significant reductions in morning cortisol (P < .001), along with lower anxiety (Hamilton Anxiety Rating Scale) and lower scores on the Depression, Anxiety and Stress Scale (DASS-21). Two solid trials, same direction on cortisol — that's why the physiological claim is on firm ground.
A 28% cortisol drop sounds dramatic, but cortisol swings naturally by the hour and by the day, and a lower reading doesn't come with a guarantee about how you'll feel. The interesting scientific question isn't "does the number move?" (it does) but "does moving the number translate into a calmer, better-functioning person?" That's where the evidence gets more honest — and more interesting.
The Catch: Lower Cortisol Doesn't Always Mean Less Stress
Here's where 2025 added a useful reality check. A systematic review and meta-analysis by Albalawi (2025) in Nutrition and Health pooled the trials measuring cortisol and perceived stress separately — seven studies for cortisol, six for perceived stress, 488 participants in all. The cortisol result was clear and significant: a drop of about 1.16 µg/dL (95% CI −1.64 to −0.69, P < 0.001). But the perceived-stress result — how stressed people actually rated themselves — was not statistically significant (SMD −0.355, P = 0.40). In plain terms: the hormone reliably fell, but the feeling didn't reliably follow.
That's not the whole story, though, and this is where honesty matters. A different 2025 systematic review, by Bachour and colleagues in BJPsych Open, pooled a larger set — 15 studies and 873 participants — and did find statistically significant reductions in cortisol, the Perceived Stress Scale, and the Hamilton Anxiety scale (anxiety improving by about 3.5 points at eight weeks). Yet even that more positive review reported no significant improvement in participants' quality of life — a reminder that a better score on a stress questionnaire isn't the same as a noticeably better daily existence.
So why do two 2025 meta-analyses disagree on perceived stress? Because they included different sets of trials, the individual studies are small, and the results scatter (Albalawi reported moderate heterogeneity, I² = 50.9%). The fair summary is: the cortisol-lowering effect is the most consistent finding across the literature, while the subjective stress benefit is real in some trials but not dependable across all of them.
Ashwagandha and Cortisol: The Evidence at a Glance
| Study | Design | Dose | What it found |
|---|---|---|---|
| Chandrasekhar et al., Indian J. Psychol. Med., 2012 | 60-day RCT (n=64) | 300 mg ×2/day | Serum cortisol −27.9% vs −7.9% placebo; PSS −44% |
| Lopresti et al., Medicine, 2019 | 60-day RCT (n=60) | 240 mg/day | Morning cortisol down (P<.001); lower anxiety & DASS-21 |
| Albalawi, Nutrition and Health, 2025 | Meta-analysis (n=488) | Varied | Cortisol significantly down; perceived stress not significant |
| Bachour et al., BJPsych Open, 2025 | Meta-analysis (15 studies, n=873) | Varied | Cortisol, PSS & anxiety down; quality of life unchanged |
Dose, Extract, and How Long It Takes
If you look at the trials that actually moved cortisol, a pattern emerges. The doses cluster around 240–600 mg per day of a concentrated root extract, usually a standardized branded form (KSM-66 and Sensoril are the two most studied). This matters more than it sounds: "ashwagandha" on a shelf can mean wildly different amounts of active withanolides, and a cheap, low-concentration powder is not the same product the studies used.
Timing is the other honest caveat. These weren't overnight effects — the cortisol and stress changes showed up over six to eight weeks of daily use, not after a single dose. So the realistic expectation, if the research applies to you at all, is a gradual shift over roughly two months of consistent use of a properly standardized extract — not a same-day calm.
One thing the studies do not establish is a personalized "cortisol-lowering dose" for any individual, or that more is better. Higher doses haven't been shown to be proportionally more effective, and — as the next section covers — they may carry more risk. Any actual dosing decision belongs with a clinician who knows your health history, not a supplement label.
Is It Safe? The Liver Signal You Should Know About
In the clinical trials, ashwagandha was generally well tolerated over a couple of months, with mostly mild side effects. But there's an important safety story that the "natural stress reliever" marketing tends to leave out: a documented, if uncommon, link to liver injury.
The U.S. National Institutes of Health's LiverTox database now lists ashwagandha as an established, if rare, cause of clinically apparent liver injury. A 2024 scoping review in Cureus gathered 25 reported patients across 13 publications; the typical picture was jaundice (in about 78% of cases) appearing weeks to months after starting a supplement, and it usually — though not always — resolved after stopping. Fatal cases and transplants have been reported mainly in people with existing liver disease.
Ashwagandha should be avoided in cirrhosis or advanced liver disease, in pregnancy and breastfeeding, and used cautiously with thyroid conditions (it can nudge thyroid hormone levels) or thyroid medication. If you develop dark urine, yellowing skin or eyes, or unusual fatigue and nausea while taking it, stop and see a doctor. Because supplements aren't tightly regulated, actual contents can also vary between brands.
What the Evidence Does and Doesn't Support
Pulling the research into one honest summary:
- Well supported: ashwagandha lowers cortisol — this is the most consistent finding, seen in individual RCTs and confirmed by 2025 meta-analyses.
- Mixed but promising: a reduction in self-rated stress and anxiety — found in several trials and one 2025 review, but not confirmed by another, so it's real for some people, not guaranteed.
- Not established: a meaningful boost in overall quality of life, long-term benefits beyond ~2 months, or that the cortisol drop by itself produces any specific health outcome.
- Not supported / cautioned: ashwagandha as a treatment for any diagnosed anxiety, thyroid, or mood disorder — and it carries a genuine, if rare, liver risk that makes "it's natural, so it's safe" the wrong assumption.
The most defensible read is that ashwagandha is one of the better-studied stress supplements, with a real and repeatable effect on a stress hormone — but that a moving lab number is a weaker promise than "you'll feel better," and the second claim is where the evidence thins out.
Frequently Asked Questions
Does ashwagandha really lower cortisol?
Yes — this is its best-supported effect. A 2012 randomized trial in the Indian Journal of Psychological Medicine found a concentrated root extract cut serum cortisol by about 28% over 60 days versus placebo, and 2025 meta-analyses confirm a statistically significant cortisol reduction across studies. What's less certain is whether that hormonal drop reliably makes people feel less stressed, which varies across trials.
If it lowers cortisol, why might I not feel less stressed?
Cortisol is one signal in a complex stress system, and how stressed you feel depends on far more than a single hormone level. A 2025 meta-analysis in Nutrition and Health found cortisol dropped significantly but perceived-stress scores did not change significantly, while another 2025 review did find a stress-score benefit. The lab value and the lived feeling don't always move together.
How much ashwagandha did the studies use, and how long?
The trials that lowered cortisol typically used about 240–600 mg per day of a standardized, concentrated root extract (often the branded KSM-66 or Sensoril), taken daily for roughly six to eight weeks. This describes what researchers tested, not a personal recommendation — the right choice for you, if any, is a conversation with a doctor or pharmacist.
Is ashwagandha safe to take?
In trials it was generally well tolerated for a couple of months, but there's a documented, if uncommon, risk of liver injury — the NIH's LiverTox database lists it as a recognized cause of clinically apparent liver damage. It should be avoided in liver disease, pregnancy, and breastfeeding, and used cautiously with thyroid conditions. Supplement contents also vary by brand, so it's not automatically "safe because it's natural."
Should I take ashwagandha for anxiety?
The research shows a modest, mixed effect on stress and anxiety scores in generally healthy, stressed adults — not evidence that it treats a diagnosed anxiety disorder. If anxiety is disrupting your life, that deserves a proper evaluation, because effective evidence-based treatments exist. Using a supplement to manage a real disorder can quietly delay care that would work better. Talk to a clinician first.
Bottom Line
Does ashwagandha actually lower your cortisol? On the evidence, yes — that's the claim it can most honestly make, with two solid randomized trials and 2025 meta-analyses all pointing the same way. If you want the one supplement-aisle "stress" ingredient that reliably moves a real physiological marker, this is a strong candidate.
Just keep the frame calibrated. A lower cortisol number is not the same as a calmer life — the 2025 research is genuinely split on whether people feel less stressed, most trials are short and use one branded extract, and there's a real (if rare) liver risk that "natural" marketing glosses over. As a modest, time-limited experiment with a properly standardized product, it's one of the more defensible options. As a treatment for anxiety, a thyroid concern, or anything happening in your liver, it's the wrong tool — and that's a conversation for a doctor, not a label.
Sources
- Chandrasekhar K, Kapoor J, Anishetty S. "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, 2012;34(3):255–262. PMC (NIH)
- Lopresti AL, Smith SJ, Malvi H, Kodgule R. "An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: A randomized, double-blind, placebo-controlled study." Medicine (Baltimore), 2019;98(37):e17186. PMC (NIH)
- Bachour G, et al. "Effects of Ashwagandha Supplements on Cortisol, Stress, and Anxiety Levels in Adults: A Systematic Review and Meta-Analysis." BJPsych Open, 2025. PMC (NIH)
- Albalawi AA. "Dual impact of Ashwagandha: Significant cortisol reduction but no effects on perceived stress — A systematic review and meta-analysis." Nutrition and Health, 2025;31(4). SAGE Journals
- National Institutes of Health, LiverTox: Clinical and Research Information on Drug-Induced Liver Injury — "Ashwagandha." NCBI Bookshelf
- Philips CA, et al. "Ashwagandha (Withania somnifera)-Associated Liver Injury: A Scoping Review of Clinical Characteristics and Safety Considerations." Cureus, 2024. Cureus
This article summarizes published research for general educational purposes and is not medical advice. It does not diagnose, treat, or recommend any specific supplement, dose, or course of action for any individual. Dietary supplements are not a substitute for evaluation and treatment of stress, sleep, thyroid, liver, or mental-health conditions. Research evolves and findings can be revised — talk to your doctor or a licensed healthcare provider before starting ashwagandha or any supplement, especially if you are pregnant, breastfeeding, have a liver or thyroid condition, or take other medication. Information is current as of August 2026.