Ayurveda

AshwagandhaWithania somnifera

Q: Is ashwagandha a gut herb?

Not in the tradition: Ayurveda classes it as a strengthening and rejuvenating herb. Its gut link in research is through stress and through two trials of a blend of ashwagandha and okra in functional constipation. We could not find a controlled trial of ashwagandha alone in IBS.

Q: What did the constipation trials show?

In 135 adults with Rome IV functional constipation, 60 days of 300 mg or 500 mg a day of an ashwagandha-okra blend lowered constipation symptom and quality-of-life scores and gastrointestinal transit time compared with placebo (P < 0.001). A smaller 14-day trial of 48 adults had the same direction. Both tested a proprietary blend, not ashwagandha alone.

Q: Does ashwagandha lower cortisol?

In a 2024 meta-analysis of nine trials with 558 patients, it lowered serum cortisol by 2.58 units compared with placebo, alongside lower stress and anxiety scores.

Q: Can ashwagandha harm the liver?

Case series describe it. Five patients in Iceland and the US had jaundice from ashwagandha supplements; liver tests recovered in 1 to 5 months in four. In an Indian series, three of eight patients with single-ingredient formulas died; all three had acute-on-chronic liver failure on top of existing liver disease.

Q: Does it affect the thyroid?

In a trial of 50 adults with subclinical hypothyroidism, 600 mg a day for 8 weeks changed TSH, T3 and T4 versus placebo. That is why people on thyroid medicine appear in the safety literature.

A stress herb, not a classical gut herb: nine trials (558 people) lowered stress scores, and one okra-plus-ashwagandha blend cut constipation scores in 135 adults.

Botanical name: Withania somnifera
Part used: root
Also called: Sanskrit Ashwagandha, Vajigandha; Hindi Asgandh, Asgand, Ashwagandha; Indian ginseng, Winter cherry
Used in: Ayurveda
Taken for: Stress and the gut, Constipation
Sold as: root powder (churna), capsules, tablets, standardized root extract, tincture, gummies

What is meant by ashwagandha

Ashwagandha is the root of Withania somnifera, a small shrub of the nightshade family that grows in India, Africa and the Middle East. In Ayurveda it is one of the main rasayana (rejuvenating) herbs, used for strength, sleep and stamina rather than for digestion.

It is sold as a dried root powder (churna) that is stirred into milk or water, as capsules and tablets, and as standardized root extracts with a stated percentage of withanolides, the plant’s signature steroidal compounds. Most clinical trials use one of a handful of branded root extracts, not the plain powder. For the gut, ashwagandha is tested mainly through its stress effect, plus a small number of constipation trials of a blend with okra. We looked for a controlled trial of ashwagandha alone in IBS and could not find one.

In the traditions

Ayurveda (about Ayurveda)

Ayurvedic texts, including the Charaka Samhita, Sushruta Samhita, Ashtanga Hridaya and Bhavaprakasha Nighantu, are cited for ashwagandha’s tastes as bitter, astringent, sweet and pungent, its qualities as unctuous and light, its potency as hot and its post-digestive effect as sweet. The tradition lists its action on the doshas as calming kapha and vata. It classes it as balya (strengthening), rasayana (rejuvenating) and vajikara (supporting vitality), and as a remedy for weakness and swelling. This is a restorative herb in the tradition, not a digestive or bowel herb, which is why the gut research is about its stress effect. These are the tradition’s claims.

What the plant contains

The root contains withanolides (steroidal lactones such as withaferin A), alkaloids and saponins. In rats, a root-extract rectal gel was tested in a chemically induced colitis model and reported anti-inflammatory and mucosa-restoring activity. In human trials the stress effect shows up as lower cortisol and lower anxiety scores. Whether that stress effect reaches the gut is a hypothesis; it has not been shown by the trials below.

What has been tested in people

Most of the human evidence is about stress. A 2024 meta-analysis of nine randomized controlled trials with 558 patients found ashwagandha formulations lowered the Perceived Stress Scale by a mean 4.72 points, the Hamilton Anxiety Scale by 2.19 points and serum cortisol by 2.58 units compared with placebo; four of the nine trials reported mild to moderate adverse events. Two of the individual trials: 64 adults with chronic stress took 300 mg of a full-spectrum root extract twice a day for 60 days and had larger drops in all stress scales (P < 0.0001) and serum cortisol (P = 0.0006) than placebo; 60 stressed adults took 240 mg of a standardized extract once a day for 60 days and had a larger fall in the Hamilton Anxiety score (P = 0.040), no significant difference on DASS-21 (P = 0.096) and lower morning cortisol (P < 0.001).

For the gut itself there are two randomized trials of CL18100F4, a proprietary blend of standardized ashwagandha root extract and okra fruit extract, in functional constipation. In the first, 48 adults took 300 mg, 500 mg or placebo for 14 days, and constipation symptom scores fell more with the blend (P < 0.0001). In the second, 135 adults meeting Rome IV criteria took 300 mg, 500 mg or placebo for 60 days, and the blend reduced constipation symptom and quality-of-life scores and gastrointestinal transit time (P < 0.001), with relief reported from day 7. Blood markers moved too: lower cortisol, IL-6 and zonulin, and higher serotonin, gastrin, IL-10 and DAO. Both trials tested the same proprietary blend, not ashwagandha alone, and share an author, so neither can say what ashwagandha does without okra.

Not tested: ashwagandha alone against placebo for constipation, IBS or reflux, and long-term gut effects.

Study	Dose	What it found
Meta-analysis of 9 randomized trials, 558 patients, stress and anxiety PMID 39348746	Various extracts	Perceived Stress Scale lower by 4.72 points, Hamilton Anxiety by 2.19, cortisol by 2.58 units vs placebo; 4 of 9 trials reported mild to moderate adverse events
Randomized, double-blind, placebo-controlled trial, 64 adults with chronic stress PMID 23439798	300 mg full-spectrum root extract twice a day, 60 days	Larger falls in all stress scales (P < 0.0001) and serum cortisol (P = 0.0006) than placebo
Randomized, double-blind, placebo-controlled trial, 60 stressed adults PMID 31517876	240 mg standardized extract once a day, 60 days	Hamilton Anxiety lower than placebo (P = 0.040); DASS-21 not significant (P = 0.096); morning cortisol lower (P < 0.001)
Randomized, double-blind, placebo-controlled trial, 48 adults with functional constipation (ashwagandha plus okra blend) PMID 37543151	300 mg or 500 mg of the blend a day, 14 days	Lower constipation symptom, quality-of-life and GI symptom scores than placebo (P < 0.0001); no adverse events reported
Randomized, double-blind, placebo-controlled trial, 135 adults with functional constipation (ashwagandha plus okra blend) PMID 38691810	300 mg or 500 mg of the blend a day, 60 days	Lower constipation symptom scores and gastrointestinal transit time than placebo (P < 0.001); relief from day 7; no major adverse events

Doses used in trials and traditional preparations

The stress trials used 240 mg a day of a standardized extract for 60 days, or 300 mg twice a day of a full-spectrum root extract for 60 days. The two constipation trials gave 300 mg or 500 mg a day of the ashwagandha-okra blend, for 14 days in the first and 60 days in the second. A thyroid trial used 600 mg a day of a root extract for 8 weeks. The abstracts do not give the withanolide content of every extract, so doses are not comparable across brands. Traditional forms include the dried root powder (churna) and decoctions.

Treat these figures as a record of what was studied. Whether any amount of ashwagandha suits a particular person is a question for a clinician or pharmacist who knows their history.

Safety

In the stress trials, adverse effects were mild and comparable to placebo in one trial and absent in another. Liver injury is the documented serious risk. A case series of five patients (three from Iceland, two from the US DILIN network) described jaundice, itching and a cholestatic or mixed liver injury 2 to 12 weeks after starting ashwagandha supplements; liver tests normalized in 1 to 5 months in four of five. A larger case series from India found 23 patients, 8 of them with single-ingredient formulas; five of the eight had underlying chronic liver disease, three presented with acute-on-chronic liver failure and all three died. Chemical analysis of the implicated products found no adulteration. We found no pregnancy or breastfeeding safety trials. On contamination, a 2008 study found 20.7% of Ayurvedic products bought online contained lead, mercury or arsenic, and ashwagandha was not singled out.

Drug interactions

In a trial of 50 adults with subclinical hypothyroidism, 600 mg a day of root extract for 8 weeks changed thyroid hormone levels (TSH, T3 and T4) compared with placebo, so effects on thyroid medicines are a documented question. The liver cases above include people taking other supplements, and the Indian series found the worst outcomes in people with existing liver disease. We found no formal interaction studies with other medicine classes.

Products in the catalog with ashwagandha

These catalog entries list ashwagandha or one of its preparations among their active ingredients. Each page shows the amount on the label, the trials behind it and what buyers report.

GLP-1 SOS Daily Gut Relief 3.9 out of 5 from 623 ratings from Amazon · $1.63 a day Silver Fern Brand Motility 3.8 out of 5 from 122 ratings from Amazon · $2.22 a day Nuora Gut Ritual 2.2 out of 5 from 39 ratings from Amazon · $1.30 a day

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Is ashwagandha a gut herb?