The short answer
Ashwagandha can cause drowsiness, which matters when taking clozapine. A small number of clozapine recipients have used a standardized extract in a trial, but their outcomes were not reported separately. Evidence does not establish a mandatory separation interval or universal avoidance rule.
What this answer covers
Oral Withania somnifera preparations; Sensoril trial findings cannot be extended to every root, leaf or mixed product.
- Supplement or preparation
- Withania somnifera
- Medication ingredient
- clozapine
What has been studied
A 2018 study included five clozapine recipients given standardized ashwagandha extract and three given placebo. It reported no separate results for these eight people, so it cannot tell us the specific interaction risk. Across the entire study, sleepiness was more common with the extract; adverse-event differences were not statistically significant.
Benefit is uncertain
The earlier study found improvements in some schizophrenia symptom scores. A 2026 trial of 47 people did not find improvement in symptoms, stress or inflammatory measures. Neither establishes a reliable benefit specifically alongside clozapine.
Why the product matters
The earlier trial used a standardized extract under supervision. Ashwagandha products may contain root, leaf or both, and NCCIH lists drowsiness and possible interactions with sedatives. Clozapine already impairs alertness and can contribute to falls. Additional drowsiness is a reasonable precaution, with its size unknown.
Timing and next steps
No protective spacing interval was established. Discuss the exact preparation and your current medicines with the clozapine team before starting it. Report new troublesome sleepiness or unsteadiness, and avoid driving while impaired. The trial regimen is not a dose recommendation for self-treatment.
Evidence and practical considerations
Timing & monitoring
Product variability and somnolence support review, but the small exposed clozapine subgroup has no separate outcomes and does not establish universal avoidance or protective spacing.
- Exact scope
- Oral Withania somnifera preparations; Sensoril trial findings cannot be extended to every root, leaf or mixed product. with Oral clozapine, RxNorm 2626 IN.
- Medication form and route
- oral clozapine; oral supplement
What remains uncertain
- No quantified clozapine-specific interaction or validated spacing intervention.
Factors that may matter: Exact preparation; Other medicines and baseline clinical status.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed clozapine.
Clozapine causes sedation and impaired performance, can contribute to falls, and carries dose-related seizure risk. CYP1A2, CYP3A4 and CYP2D6 participate in metabolism. Proposed therapeutic activity includes dopamine D2 and serotonin 5-HT2A receptor antagonism.
How this applies: Medication-specific safety context only; no direct botanical interaction or automatic dose change is established.
No named interaction with these counterparties or measured combined risk.
Source 2: original human clinical study
psychiatrist.com · Source check Sep 10, 2026
Population: 66 efficacy participants with schizophrenia or schizoaffective disorder.
Somnolence was more common with extract overall but adverse-event differences were not statistically significant; transient mild-to-moderate events. Negative, general and total symptom scores improved, but positive symptoms did not. Five extract recipients and three placebo recipients received clozapine, without separately reported subgroup outcomes.
How this applies: Interpret only within the stated preparation, population and endpoints.
Small clozapine subgroup; mixed medications and permitted medication changes. No clozapine-specific toxicity, concentrations or spacing result.
Source 3: original human clinical study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 47 randomized schizophrenia participants, 24 extract and 23 placebo.
No significant benefit on PANSS, CGI, perceived stress or inflammatory markers.
How this applies: Interpret only within the stated preparation, population and endpoints.
Abstract does not establish a clozapine-specific subgroup, dose or detailed interaction safety. Small sample and pandemic disruption.
Source 4: federal supplement safety guidance
nccih.nih.gov · Source check Sep 10, 2026
Population: Users of the named supplement.
Preparations can cause drowsiness and might interact with sedatives; preparations vary.
How this applies: Supplement-specific guidance interpreted alongside the clozapine label.
General guidance does not quantify a clozapine interaction or establish protective spacing.
Research assessment: · Open full citations ↗
Side effects & toxicity
Possible additional impairment warrants individual review because clozapine causes sedation and the supplement has sedative effects or a stated theoretical sedative-interaction concern; clinical magnitude is unmeasured.
- Exact scope
- Oral Withania somnifera preparations; Sensoril trial findings cannot be extended to every root, leaf or mixed product. with Oral clozapine, RxNorm 2626 IN.
- Medication form and route
- oral clozapine; oral supplement
What remains uncertain
- No quantified clozapine-specific interaction or validated spacing intervention.
Factors that may matter: Exact preparation; Other medicines and baseline clinical status.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed clozapine.
Clozapine causes sedation and impaired performance, can contribute to falls, and carries dose-related seizure risk. CYP1A2, CYP3A4 and CYP2D6 participate in metabolism. Proposed therapeutic activity includes dopamine D2 and serotonin 5-HT2A receptor antagonism.
How this applies: Medication-specific safety context only; no direct botanical interaction or automatic dose change is established.
No named interaction with these counterparties or measured combined risk.
Source 2: original human clinical study
psychiatrist.com · Source check Sep 10, 2026
Population: 66 efficacy participants with schizophrenia or schizoaffective disorder.
Somnolence was more common with extract overall but adverse-event differences were not statistically significant; transient mild-to-moderate events. Negative, general and total symptom scores improved, but positive symptoms did not. Five extract recipients and three placebo recipients received clozapine, without separately reported subgroup outcomes.
How this applies: Interpret only within the stated preparation, population and endpoints.
Small clozapine subgroup; mixed medications and permitted medication changes. No clozapine-specific toxicity, concentrations or spacing result.
Source 3: original human clinical study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 47 randomized schizophrenia participants, 24 extract and 23 placebo.
No significant benefit on PANSS, CGI, perceived stress or inflammatory markers.
How this applies: Interpret only within the stated preparation, population and endpoints.
Abstract does not establish a clozapine-specific subgroup, dose or detailed interaction safety. Small sample and pandemic disruption.
Source 4: federal supplement safety guidance
nccih.nih.gov · Source check Sep 10, 2026
Population: Users of the named supplement.
Preparations can cause drowsiness and might interact with sedatives; preparations vary.
How this applies: Supplement-specific guidance interpreted alongside the clozapine label.
General guidance does not quantify a clozapine interaction or establish protective spacing.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Prepared evidence-based article with explicit preparation and endpoint limits. | |
| Research summary published |
Article revision: eb62b32cd41c13d2
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.