Pick the extract on your label, type its milligrams and how many servings a day, and choose stress or sleep. You see your daily amount against the doses NIH ODS’s trials used for that kind of extract — KSM-66 and Shoden capsules are not the same milligrams — how often they gave it, and ODS’s safety notes. It never tells you how much to take.
Against the trials of the same extract
Inside the doses the stress trials used 300 mg × 2 servings = 600 mg a day of KSM-66
NIH ODS: “The ashwagandha dose varied from 240 to 1,250 mg/day of extract or 12,000 mg/day of whole root granules, which is equivalent to 6,000 mg of root powder.” And: “In several studies, the benefits appeared to be greater with doses of 500 to 600 mg/day than with lower doses.” It is also inside the 300 to 600 mg of root extract an international taskforce provisionally recommends for generalized anxiety disorder.
That places the label against the trials; it is not a dose for you. Your doctor or pharmacist knows your medicines.
Trials of the same kind (stress), as NIH ODS describes them
- Prolanza: 300 mg a day, 90 days. “The extract was standardized to contain 15 mg withanolides per 300-mg capsule, and participants took one capsule daily.”
- Gaia Herbs: 700 mg a day, 30 days. “The extract contained 2.5 mg withanolides per 350-mg capsule, and participants took two capsules daily.”
- Witholytin: 400 mg a day, 84 days. “Participants took an ashwagandha root extract (Witholytin, which contains 200 mg hydroalcoholic extract of ashwagandha root standardized to 1.5% withanolides) or placebo twice daily for 12 weeks. Compared with placebo, ashwagandha did not reduce perceived stress, but it did reduce fatigue.”
The trials NIH ODS describes gave it once a day (Prolanza) or twice (KSM-66, Shoden, Gaia Herbs, Witholytin). ODS gives no time of day.
NIH ODS: “Ashwagandha appears to be well tolerated for up to about 3 months of use, but its long-term safety is not known. Common side effects (e.g., loose stools, nausea, drowsiness) are usually mild. However, there are a few reports of more serious side effects, including adverse effects on liver function. Ashwagandha might also affect thyroid function and interact with some medications. Some experts advise against the use of ashwagandha by women who are pregnant and by men with hormone-sensitive prostate cancer.” And: “Ashwagandha might also interact with other medications, including antidiabetes medications, antihypertensives, immunosuppressants, and sedatives.”
This is not medical advice and it never suggests a dose: it places a label against published trials. Ask your doctor or pharmacist first — especially in pregnancy, with a thyroid condition, liver disease or hormone-sensitive prostate cancer, or with diabetes, blood-pressure, immune-suppressing or sedative medicines.
NIH’s Office of Dietary Supplements: the stress trials gave 240 to 1,250 mg a day of extract, and “the benefits appeared to be greater with doses of 500 to 600 mg/day than with lower doses”. The sleep trials gave 250 to 600 mg a day of KSM-66 root extract, or 120 mg of Shoden. Which extract your label holds changes what the milligrams mean.
How to use it
Find the extract’s name on the label — KSM-66, Shoden, Sensoril — or pick root extract, root powder or “does not say”. Type the milligrams of ashwagandha in one serving (the Supplement Facts line) and the servings you take a day, and pick stress or sleep. The checker multiplies them into a daily amount and places it against the trials of the same kind NIH ODS describes, lists those trials with their own words, and shows ODS’s safety paragraph. It does not tell you how much to take.
Why the extract matters
Extracts are made differently and dosed differently. In ODS’s own descriptions, the KSM-66 sleep trial’s “extract was standardized to a withanolide content of more than 5% per 300-mg capsule, and participants took two capsules each day”, while the Shoden trial’s “extract was standardized to contain 21 mg of withanolide glycosides per 60-mg capsule, and participants took two capsules each day.” That is 600 mg against 120 mg a day — both studied doses, of different products. ODS sums up the sleep studies: “The dose of the ashwagandha supplement used in these studies ranged from 250 to 600 mg/day as a root extract (KSM-66) or, in one study, 120 mg/day of a root and leaf extract (Shoden).” And the stress studies: “The ashwagandha dose varied from 240 to 1,250 mg/day of extract or 12,000 mg/day of whole root granules, which is equivalent to 6,000 mg of root powder.” So the checker never reads a Shoden label against KSM-66’s numbers, and where ODS describes no trial of a kind for a goal — Sensoril for sleep, for example — it says so instead of guessing.
| Trial | For | A day | How often | Days |
|---|---|---|---|---|
| KSM-66 | sleep | 600 mg | twice | 56 |
| Shoden | sleep | 120 mg | twice | 42 |
| Prolanza | stress | 300 mg | once | 90 |
| Gaia Herbs | stress | 700 mg | twice | 30 |
| NooGandha | stress | 225 or 400 mg | — | 30 |
| Witholytin | stress | 400 mg | twice | 84 |
One of them is a reminder that a trial can find nothing for the question you care about: Witholytin’s 12-week trial reported that “Compared with placebo, ashwagandha did not reduce perceived stress, but it did reduce fatigue.”
When to take it
The trials ODS describes gave ashwagandha once a day (Prolanza) or twice (KSM-66, Shoden, Gaia Herbs, Witholytin), and ODS gives no time of day — so this page gives none either. How long the trials ran, and when they first reported a difference, is in the How Long Until It Works tool: for stress, after 8 weeks.
Safety, in ODS’s words
“Ashwagandha appears to be well tolerated for up to about 3 months of use, but its long-term safety is not known.” “Common side effects (e.g., loose stools, nausea, drowsiness) are usually mild.” “However, there are a few reports of more serious side effects, including adverse effects on liver function. Ashwagandha might also affect thyroid function and interact with some medications. Some experts advise against the use of ashwagandha by women who are pregnant and by men with hormone-sensitive prostate cancer.” And: “Ashwagandha might also interact with other medications, including antidiabetes medications, antihypertensives, immunosuppressants, and sedatives.” There is no official upper limit for ashwagandha, so the checker never calls an amount safe; above the highest trial dose it says no trial tested it.
Worked examples
- KSM-66, 300 mg, twice a day, for stress (the page’s example): 600 mg a day — inside the stress trials’ 240 to 1,250 mg, and inside the 500 to 600 mg where several studies saw greater benefits.
- The same label, for sleep: 600 mg a day — the top of the sleep trials’ 250 to 600 mg, the dose at which “The benefits were more prominent”.
- Shoden, 60 mg, twice a day, for sleep: 120 mg a day — the amount the Shoden study used.
- Sensoril, 250 mg, twice a day, for sleep: no sleep trial of this extract in ODS’s studies, so there is nothing to read it against.
- An unnamed extract, 1,500 mg a day, for stress: above every extract dose in the stress trials — not an amount any of them tested.
Common mistakes
- Comparing milligrams across extracts. 120 mg of Shoden and 600 mg of KSM-66 were each a trial’s dose.
- Reading a range as a target. These are the amounts studied, not a dose for you.
- Taking it for months on end without asking. ODS: tolerated “for up to about 3 months”, long-term safety “not known”.
- Forgetting your other medicines. Your pharmacist can check them; this page does not.
Frequently asked questions
What is the right ashwagandha dosage?
No official body sets one for healthy people. ODS’s stress trials gave 240 to 1,250 mg a day of extract, with greater benefits in several at 500 to 600 mg; its sleep trials gave 250 to 600 mg of KSM-66 or 120 mg of Shoden. An international taskforce provisionally recommends 300 to 600 mg of root extract standardized to 5% withanolides — for generalized anxiety disorder, a diagnosis, not everyday stress.
When should I take ashwagandha?
ODS gives no time of day. The trials it describes gave it once a day (Prolanza) or split into two doses (KSM-66, Shoden, Gaia Herbs, Witholytin).
How long does ashwagandha take to work?
In the stress trials, the first reported difference from placebo came after 8 weeks; ODS adds that sleep benefits were “more prominent when the dose was 600 mg/day and when the treatment duration was at least 8 weeks”. The How Long Until It Works tool dates each checkpoint from your start.
Is KSM-66 dosed differently from Sensoril or Shoden?
Yes. ODS’s KSM-66 sleep trial gave two 300 mg capsules a day; its Shoden trial gave two 60 mg capsules. Sensoril appears in ODS’s stress review, not in its sleep studies. Read your label against the trials of its own extract.
How much ashwagandha is too much?
There is no official upper limit. The highest extract dose in ODS’s stress studies was 1,250 mg a day, and ODS says it “appears to be well tolerated for up to about 3 months of use, but its long-term safety is not known”. More than any trial gave is a conversation with your doctor first.
Who should not take ashwagandha?
ODS: “Some experts advise against the use of ashwagandha by women who are pregnant and by men with hormone-sensitive prostate cancer”, and it notes possible effects on the liver and thyroid and interactions with antidiabetes, blood-pressure, immune-suppressing and sedative medicines. Ask your doctor or pharmacist.
Read next
- Ashwagandha vs rhodiola rosea: which adaptogen wins?
- Best adaptogen combinations for mood, energy and sleep
- 5 adaptogenic herbs that help relieve stress and fatigue
- Ashwagandha and serotonin
- Ginkgo biloba vs ashwagandha: are they nootropics?
This is not medical advice, and nothing here diagnoses, treats or prevents anything: it places a label against published trials and never suggests a dose. Ask your doctor or pharmacist first — especially in pregnancy, with a thyroid or liver condition, or with blood thinners, antidepressants or blood-pressure medication. Some links on this site are affiliate links: I buy what I review at full price, and a commission never changes a verdict.