Supplements and stress
Ashwagandha and Low Cortisol: Can It Lower Your Stress Hormone Too Far?
Reviewed by a qualified clinician · analysed at UKAS-accredited UK labs (ISO 15189)
Last reviewed July 20267 min read
Every Helvy guide is written by our health editors, then checked by a qualified clinician before it goes live and re-checked as the science moves. We name clinical roles, not individuals, until each reviewer has agreed to be credited publicly. This is wellness guidance to help you understand your own data, not a diagnosis.
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Ashwagandha does lower cortisol, your main stress hormone. That is its best-proven effect, and for most people it is mild. But a 2026 case report links very high doses, taken for over a year, to cortisol falling too low. The only way to know your own level is a blood test.
Not sure where your cortisol sits? Build your test →As of July 2026.Ashwagandha is the UK’s top-selling calming supplement, and most articles ask only whether it lowers cortisol. A fresh 2026 case report raises the opposite question, one worth taking seriously: can it lower cortisol too far? This guide covers both sides, and what a blood test can show.
Here is the short version. Ashwagandha works on cortisol. Most of the time that is helpful, and mild. The new worry is about dose and time, not the herb itself.
1. Does ashwagandha actually lower cortisol?
Yes, and the evidence is unusually good for a supplement. Cortisol is your main stress hormone, made by the adrenal glands. A 2025 meta-analysis in BJPsych Open pooled 15 randomised trials in 873 stressed adults. It found a clear, statistically significant fall in cortisol after eight weeks.
A fresh 2026 trial backs this up. Researchers in Barcelona gave 56 sub-elite athletes 600 mg of a standardised extract (KSM-66) daily for six weeks. Ashwagandha blunted the usual pre-season rise in stress hormones, reported NutraIngredients in January 2026.
So the headline is true. Ashwagandha lowers cortisol. That is exactly why the next question matters. For the wider case, including its effect on testosterone, see our guide on whether ashwagandha actually works.
2. Can it lower cortisol too far?
For most people, no. The drop seen in trials is modest, and it reverses when you stop. Short, sensible use is not the concern here.
But a case report published in January 2026 shows the tail risk. A 55-year-old woman had taken about 950 mg of ashwagandha daily for more than a year. She developed weight gain and Cushingoid features (a puffy, rounded appearance linked to a disturbed stress axis). Tests found her cortisol was low, and her adrenal glands responded poorly to a stimulation test.
Her doctors linked it to the long-term, high-dose ashwagandha. She stopped the supplement and was started on hydrocortisone to replace the missing hormone. The authors described chronic use leading to “sustained suppression of the HPA axis”, the brain-to-adrenal circuit that controls cortisol. One case does not make a supplement dangerous. It does show that more is not always better.
3. What does low cortisol feel like?
This is the hard part. Low cortisol is easy to miss, because its symptoms are vague. Tiredness, low mood, muscle weakness, poor appetite and feeling dizzy on standing are all common. The NHS makes the point directly for adrenal insufficiency, the medical name for low cortisol:
“Many of the symptoms of Addison’s disease are the same as the symptoms of other conditions.”
— NHS, Addison’s disease
That overlap is the whole problem. The same tiredness could be low cortisol, an underactive thyroid, low iron or low vitamin D. You cannot feel the difference between them. A blood test is the only way to tell them apart, which is where a full blood count and a broader panel earn their place.
4. Who is most at risk?
The case report is one person, not a population. But it points at the same risk factors every time this happens. You are more exposed if you:
- Take a high daily dose.The case used about 950 mg, well above the 240 to 600 mg used in most trials.
- Take it for many months without a break. The risk in the case built up over more than a year of daily use.
- Stack several calming supplements at once. More products rarely means more benefit, and it clouds what is doing what.
- Already have low energy you have not had checked. A new supplement on top of an unknown baseline hides the real cause.
Short, sensible use in a healthy adult is very different from a year at a heavy dose. If you have taken ashwagandha for a long time and feel newly flat, that is worth checking rather than pushing through.
5. How do you check your real level?
Cortisol is a blood marker, so you do not have to guess. A morning sample shows whether your level sits where it should, in either direction. Very high or very low results are the ones a clinician should review. Our cortisol blood test guide explains how the timing works.
Helvy’s General Energy & Wellness panel (£149, 17 markers) measures cortisol alongside thyroid (TSH and Free T4), vitamin D and B12, the other common causes of the same tiredness. It is a home finger-prick test, with results in about five working days from UKAS-accredited UK laboratories.
The point is not to scare you off a supplement that helps many people. It is to know your starting number, and to check again if you use it long term. That turns “I think it is working” into an answer. If your energy is the real issue, our tired-all-the-time guide walks through every testable cause.
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See where your cortisol really sits
Helvy’s home blood tests report cortisol, thyroid, vitamin D and B12 with clear, plain-English context, so you can tell a stress problem from a fixable one. Results in about 5 working days from UKAS-accredited UK laboratories.
Frequently asked questions
Can ashwagandha lower cortisol too much?
For most people, no. The fall in cortisol seen in trials is modest and reverses when you stop. But a 2026 case report links very high doses, taken daily for more than a year, to cortisol dropping too low and the stress axis being suppressed. Dose and duration are the risk, not short, sensible use. This is general information, not medical advice.
What are the signs of low cortisol?
They are vague and easy to miss: extreme tiredness, low mood, muscle weakness, loss of appetite and feeling dizzy on standing. The NHS notes that these overlap heavily with other conditions, so you cannot tell from symptoms alone. A blood test is the only way to know, and a very low result should be reviewed by a GP.
How much ashwagandha is too much?
Most positive trials used a standardised root extract at 240 to 600 mg a day for eight to twelve weeks. The 2026 case involved about 950 mg daily for over a year, well above that range. Staying within trial doses, and taking breaks rather than using it indefinitely, is the sensible approach. Check with a pharmacist if you take other medication.
Should I get a blood test before or after taking ashwagandha?
Both are useful. A baseline shows whether your cortisol was ever high in the first place, which many people assume without checking. A retest after a long course shows whether it has drifted too low. Take both morning samples at a similar time so the comparison is fair.