Safety of 8‐Week Administration With Ashwagandha (Withania somnifera) Root Extract in Adults With Stress and Anxiety: Findings From a Prospective, Randomized, Multi‐Center, Double‐Blinded, Placebo‐Controlled Study

ABSTRACT

Ashwagandha ( Withania somnifera ) has been recognized for enhancing physical strength, mental well‐being, and overall vitality. Despite its long‐standing use across generations, some clinical reports have noted occasional adverse events. This study compared the safety and tolerability of Ashwagandha Root Extract (ARE) in healthy adults. This was a prospective, multicenter, multinational, randomized, double‐blinded, placebo‐controlled study (n = 1002; 18 to 65 years). Participants with reported stress and anxiety were randomly assigned to receive either 600 mg/day (two divided doses) of ARE (n = 498) or a placebo (PL, n = 504) orally for 8 weeks. The primary outcome was the safety profile assessed through laboratory parameters and adverse events (AEs), while tolerability was assessed by the participants on a 7‐point Likert scale of Global Assessment of Tolerability to Therapy. Demographic and baseline characteristics were similar between groups. No serious adverse events were reported; a total of 74 AEs (7.4%) were documented, with 46 events (9.2%) in the PL group and 28 events (5.6%) in the ARE group. The most common AEs include nausea (3.2% in PL vs. 2.0% in ARE), dry mouth (1.4% in both groups), and headache (2.2% in PL vs. 0.2% in ARE). Laboratory evaluations showed no significant changes in liver function tests, renal function markers, or hematological parameters between the ARE and PL groups. Both groups maintained normal ranges for key biomarkers, including aspartate aminotransferase, alanine aminotransferase, creatinine, and hemoglobin levels throughout the study duration. Tolerability ratings showed no statistically significant difference between the groups (p = 0.487), and most of the participants rated the ARE therapy as “Good” or “Excellent.” ARE is well‐tolerated and safe in adults with stress and anxiety. These results support the use of Ashwagandha root extract as a viable non‐pharmacological treatment, warranting further exploration of its long‐term effects in diverse populations.

1. Introduction

Ashwagandha ( Withania somnifera ) has been an important part of traditional Ayurvedic medicine for over 3000 years. Its use is deeply rooted in the concept of Rasayana, which refers to rejuvenating therapies aimed at enhancing longevity, vitality, and mental well‐being. Ancient Ayurvedic texts describe Ashwagandha as an herb that promotes physical strength, energy, and resilience, making it particularly valuable for individuals experiencing physical and mental stress. Across generations, Ashwagandha has been consumed for a wide range of conditions, including fatigue, weakness, insomnia, and anxiety, all of which are exacerbated by stress (Singh et al. 2011; Samuelsson and Bohlin 2015).

In modern times, Ashwagandha's therapeutic potential has been explored in numerous clinical and preclinical studies. It is classified as an adaptogen, a natural substance that helps the body cope with stress by regulating physiological processes and protecting against the damaging effects of environmental stressors. Physiological processes regulated by adaptogens include hormonal balance, nervous system modulation, immune support, energy metabolism, cognitive function, cardiovascular stability, detoxification, antioxidant activity, and blood sugar regulation. Extensive research supports its benefits in reducing symptoms of both stress and anxiety, as well as depression, and lowering serum cortisol levels, a key indicator of the body's stress response (Penninx et al. 2021; Speers et al. 2021).

Anxiety, although distinct from stress, often co‐occurs with it and is characterized by excessive worry, apprehension, and physiological symptoms such as increased heart rate, restlessness, and sleep disturbances (Penninx et al. 2021). Studies have demonstrated that Ashwagandha's anxiolytic effects help reduce these symptoms by modulating neuroendocrine and neurotransmitter systems involved in the stress response (Speers et al. 2021). These effects are believed to be mediated through the regulation of the hypothalamic–pituitary–adrenal (HPA) axis, enhancement of γ‐aminobutyric acid (GABA)ergic signaling, and reduction of cortisol levels, thereby promoting a state of calm and improved psychological resilience (Stephens and Wand 2012).

Additionally, Ashwagandha exhibits neuroprotective (Dipankar et al. 2025), anti‐inflammatory (KrishnaRaju et al. 2023), and antioxidant properties (Namdev et al. 2023), making it valuable in managing conditions such as neurodegenerative diseases, immune dysfunction, and oxidative stress. Its ability to modulate oxidative stress has been demonstrated through the evaluation of biomarkers like malondialdehyde (MDA), superoxide dismutase (SOD) (Vittal and Vinciguerra 2025), and glutathione peroxidase (GSH) (Er et al. 2025).

While Ashwagandha has gained popularity for its broad health benefits, some studies have reported adverse events (AEs) (Raut et al. 2012). These adverse effects include gastrointestinal disturbances, drowsiness, and mild headaches (Tandon and Yadav 2020; Hanus et al. 2004). However, such AEs are typically rare and transient, resolving without long‐term consequences. However, it is important to note that not all studies have systematically or comprehensively assessed safety outcomes, and variations in study design, dosage, and population characteristics may influence reported tolerability. A growing body of research indicates that Ashwagandha root extract is generally well‐tolerated when used appropriately. Nevertheless, further rigorous and standardized safety evaluations are warranted to confirm its tolerability across diverse populations and dosing regimens. These considerations support its continued investigation as a potential intervention for stress‐ and anxiety‐related conditions (Vittal and Vinciguerra 2025).

This study was a prospective, randomized, multinational, multicenter, double‐blind, placebo‐controlled trial assessing the safety and tolerability of Ashwagandha ( Withania somnifera ) Root Extract (ARE) in adults experiencing borderline to moderate symptoms of stress and anxiety across different populations, with the majority (80%) of participants recruited from India. Participants were selected based on the presence of stress and anxiety symptoms, as these conditions are highly prevalent and associated with significant physiological and psychological burden that may affect overall well‐being and daily functioning. The rationale for focusing on this population stems from the growing evidence supporting the role of Ashwagandha in modulating stress and anxiety. This report presents the safety data from a broader clinical trial designed to evaluate the efficacy and safety of ARE in individuals presenting with stress and anxiety symptoms. While the primary focus of the overall trial is on stress and anxiety reduction, this segment specifically investigates the safety and tolerability of ARE in adult populations.

This study aims to comprehensively assess the safety and tolerability of KSM‐66 Ashwagandha root extract in healthy adults, with a primary focus on evaluating its safety profile as a stress and anxiety modulating intervention.

2. Materials and Methods

2.1. Study Design and Setting

The study was conducted at 15 sites across India, Australia, the United States, Portugal, and Africa. The clinical protocol and associated documents were approved by the Institutional Ethics Committee (ICE) at each participating site. The study was conducted in strict accordance with Good Clinical Practice (ICH GCP) guidelines, the New Drugs and Clinical Trials Rules 2019 (India), the Declaration of Helsinki (Taipei 2016), and other applicable regulations at the study sites. IEC approval was obtained prior to initiating study procedures, and all participants provided written informed consent before any study‐related activities were performed.

Participants across all study sites were recruited through standard community‐based outreach methods approved by each site's IEC. In India, recruitment was conducted through outpatient departments, referrals from collaborating clinicians, and onsite posters placed in hospitals and clinics. In the USA, Australia, Portugal, and Africa, participants were enrolled through local clinical research networks, community advertisements, and digital outreach (including email databases and clinic websites). All advertisements briefly described the study purpose, eligibility criteria, and contact information. Interested individuals were pre‐screened by telephone or in person, followed by onsite clinical screening before enrollment. The First Patient First Visit occurred at different sites between 25 June 2020 and 23 January 2024, while the Last Patient Last Visit was completed between 14 April 2022 and 04 April 2024.

2.1.1. Trial Registration

The trial was registered with the Clinical Trials Registry of India (CTRI/2020/03/024186; dated March 23, 2020; https://www.ctri.nic.in/Clinicaltrials/pmaindet2.php?EncHid=NDE1MzE=&Enc=&userName=) and ClinicalTrials.gov (NCT05684991; https://clinicaltrials.gov/study/NCT05684991?tab=table). The reporting of the study's findings adheres to the CONSORT (Consolidated Standards of Reporting Trials) guidelines.

2.2. Inclusion and Exclusion Criteria

The study included 1002 male and female adults aged 18 to 65 years having a baseline Hamilton Anxiety Rating Scale (HAM‐A) total score between 14 and 30 (Hanus et al. 2004), indicating borderline to moderate anxiety, and a Cohen's Perceived Stress Scale (PSS) score of ≥ 13, indicating average stress (≥ 13) or high stress (≥ 20) (Cohen et al. 1983), without any significant physiological or psychiatric abnormalities, were included in the study (Chandrasekhar et al. 2012). Participants who had signs and symptoms indicative of high stress, such as difficulty concentrating, physical exhaustion, anxiety, restlessness, insomnia, headaches, fatigue, loss of appetite, worry, sweating, or mental confusion, and who were willing to comply with study procedures were considered eligible for inclusion.

Exclusion criteria encompassed individuals with depressive episodes, suicidal tendencies, panic disorder, social phobia, obsessive‐compulsive disorder, alcohol dependency, schizophrenia, mania, or post‐traumatic stress disorder. Participants receiving medications known to influence stress and anxiety, such as corticosteroids, antidepressants, antipsychotics, mood stabilizers, or anti‐epileptic drugs, were also excluded. Additionally, individuals with a history of alcohol or substance abuse, any clinically significant cardiovascular, renal, metabolic, hematological, neurological, systemic, or infectious diseases, malignant tumors, or other acute illnesses were not eligible. Furthermore, those who had undergone surgery within the past year, consumed dietary or nutritional supplements or multivitamins in the month prior to the study, or had been practicing meditation or relaxation techniques for at least 3 months were also excluded.

2.3. Randomization and Blinding

Enrolled participants were assigned unique serial numbers and randomized to receive either ARE (n = 498) or a placebo (PL, n = 504). Participants were randomized to the treatment groups using a computer‐generated (SAS 9.2, SAS Institute, Cary, NC, USA) site‐specific block randomization schedule (block size of four) in a 1:1 ratio, and no stratification was made. Pre‐sealed and sequentially numbered medication packs in identical capsule form were prepared according to the randomization code and distributed to participants based on their serial numbers, ensuring allocation concealment. The product kits were distributed according to expected enrolment at each site to maintain an approximate balance between placebo and ARE arms. Both the active and placebo capsules were identical in size, shape, and appearance. The placebo formulation (pharmaceutical‐grade starch blended with a small amount of inert coloring excipient) was visually matched to the active formulation to ensure a similar appearance through the capsule shell. Both were filled to the same weight and packaged identically. As the capsules were consumed whole with water, no perceptible differences in color, taste, or odor were noted by participants. As this was a double‐blind study, blinding was maintained using sequentially numbered opaque sealed envelopes (SNOSE). Both the participants and the research team, including investigators, site staff, and study monitors, were blinded to the treatment allocations. The randomization codes were generated and securely maintained by an independent statistician from the central coordinating center. Pre‐labeled, identical medication kits were prepared according to the randomization list and distributed to study sites. The codes remained inaccessible to all study personnel until the completion of data analysis or unless emergency unblinding was warranted. Additionally, to minimize bias, a non‐affiliated researcher, who remained blind to treatment allocation, collected assessment data at each scheduled visit.

2.4. Interventions

Participants randomized to the intervention group received Ashwagandha ( Withania somnifera (L.) Dunal) root extract (ARE) capsules, while those in the placebo group received matching placebo capsules. The investigational product was a commercially available, root‐only extract of Ashwagandha manufactured by Ixoreal Biomed, California, USA. The botanical identity of Withania somnifera was authenticated using standard pharmacognostic and taxonomic procedures, and the extract was produced exclusively from the dried roots of the plant. The raw botanical material was cultivated under Good Agricultural and Collection Practices (GACP) in regions with optimal agroclimatic conditions, including annual rainfall of 650–750 mm and soil pH ranging from 7.5 to 8.0. The extract was prepared using a green chemistry‐based extraction process, devoid of alcohol or chemical solvents. The final product was standardized to contain > 5% total withanolides, quantified using a validated high‐performance liquid chromatography (HPLC) method, with withaferin A maintained at < 0.1%, ensuring consistency and safety across batches. Physicochemically, the extract was a light yellowish‐brown, slightly hygroscopic powder, soluble in water, with a measured pH of 4.76 (5% w/v aqueous solution). The bulk density was 0.58 g/cc, with a tapped bulk density of 0.78 g/cc.

Comprehensive quality control testing was performed on each batch in accordance with Current Good Manufacturing Practices (cGMP) and Current Good Laboratory Practices (cGLP). The product was subjected to organoleptic evaluation, moisture content analysis, microscopic examination, ash and pH testing, and bioactive content analysis. Safety testing confirmed that heavy metal levels were below quantification limits (Pb < 0.05 ppm, Cd < 0.01 ppm, As < 0.01 ppm, Hg < 0.01 ppm). Microbiological testing complied with USP <561> limits, with confirmed absence of Escherichia coli , Salmonella spp., and Staphylococcus aureus . Additional testing verified acceptable limits for aflatoxins and pesticide residues. Stability studies demonstrated that the extract remained stable for up to 3 years when stored under recommended conditions (22°C ± 3°C).

Participants in the ARE group received 300 mg capsules orally, twice daily, once after breakfast and once after dinner, with water, for a total duration of 8 weeks. The placebo group received identically appearing capsules containing 300 mg starch, administered on the same schedule. The placebo capsules were matched to the active product in appearance, size, color, and weight to maintain blinding.

2.5. Follow‐Up Compliance

All participants completed the 8‐week follow‐up. The short intervention duration, simple dosing regimen, careful screening for compliance, and regular investigator contact with scheduled reminders contributed to the absence of loss to follow‐up.

2.6. Study Outcomes

The present manuscript focuses on the safety and tolerability evaluation of ARE in adults experiencing mild to moderate symptoms of stress and anxiety. The primary outcome of the study was the safety of ARE, assessed by the change in laboratory parameters from baseline to week 8. Safety in this study was also assessed through the monitoring and reporting of AEs throughout the 8‐week intervention period.

The secondary outcome was tolerability, evaluated using the Global Assessment of Tolerability to Therapy (GATT), which provided a comprehensive assessment of participants' overall tolerance to the therapy. These outcomes were integral in determining the overall safety profile and tolerability of Ashwagandha root extract in adults with stress and anxiety over the 8‐week period.

2.7. Study Assessments

The study comprised two on‐site visits by participants, one at baseline and one at the end of study week 8. A telephonic follow‐up was conducted at week 4 to ensure participants' compliance.

2.7.1. Safety Outcomes

2.7.1.1. Laboratory Assessments

The safety outcomes of the study were comprehensively assessed through a series of laboratory investigations and AE monitoring conducted at predefined time points. Hematological data were collected at baseline and week 8 visits. At each time point, participants underwent venous blood sampling following an overnight fast. Hematological parameters included white blood cell count, red blood cell (RBC) count, hematocrit, hemoglobin levels, and platelet count, providing insights into participants' blood health (Ajgaonkar et al. 2022). Liver function was assessed through serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels (Avigan et al. 2014), while renal function was assessed based on serum creatinine. AST and ALT levels were considered sufficient indicators for evaluating hepatic safety, as both enzymes are sensitive markers of hepatocellular integrity and early indicators of potential hepatic injury. Collectively, these tests were critical for evaluating any potential AEs of the treatment on vital organ systems and ensuring participant safety throughout the trial (Gopal et al. 2021; Chauhan et al. 2022).

2.7.1.2. AEs

All participants were monitored for any AEs and serious adverse events (SAEs) throughout the 8‐week treatment period, with reports detailing the nature, frequency, and severity of these events. Safety data were collected at baseline, week 4, and week 8 study visits. Participants were instructed to report any unusual symptoms or side effects at any time during the study and were contacted by study personnel once weekly, either in person during visits or via telephone, to ensure consistent safety follow‐up. In addition, participants maintained a diary to record any symptoms, changes in health status, or concomitant medication use between visits.

All reported AEs were categorized by the site investigators based on severity (mild, moderate, or severe), duration, and assessed for their relationship to the study product (related, possibly related, or unrelated). The monitoring process included weekly check‐ins, physical examinations, and laboratory tests to ensure that any adverse reactions were promptly identified and addressed. SAEs were to be reported to the sponsor's medical affairs team within one business day using standardized forms, regardless of their assessed relationship to the study drug.

2.7.1.3. GATT

The secondary outcome of the study, tolerability, was assessed using the GATT (Er et al. 2025). This standardized tool allowed participants to rate their overall experience with the therapy on a scale ranging from “Excellent” to “Worst.” The categories included “Excellent,” indicating no issues with tolerability, followed by “Good,” “Moderate,” “Poor,” and “Worst,” which reflected increasing levels of discomfort or adverse reactions.

2.8. Sample Size

The sample size calculation was based on a previously published study for a randomized controlled trial of ARE for stress and anxiety published by Salve et al. (2019) It was hypothesized that the Ashwagandha group would yield a change of 2.05 ± 3.8 (mean ± standard deviation) in the HAM‐A scores after 8 weeks.

Sample size estimates were performed using the G*Power software (available at the University of Düsseldorf: http://www.psycho.uni‐duesseldorf.de/abteilungen/aap/gpower3/), specifically for a two independent sample means test designed to detect an effect size of 0.54 in a parallel‐group setup (1:1), with a 5% risk of type I error (α) and 80% power. Based on these calculations, a sample of 49 subjects per group was deemed sufficient for the planned comparisons. The formal sample size calculation was based on efficacy outcomes (HAM‐A scores) from a previously published randomized controlled trial and indicated that 49 participants per group would be sufficient to detect a clinically meaningful difference. However, the present study was designed as a large, multicenter safety evaluation embedded within a broader efficacy trial. A substantially larger sample size (approximately 1000 participants) was therefore recruited to enhance the precision of safety estimates, enable detection of less frequent adverse events, and ensure adequate representation across key demographic and clinical characteristics, including gender, BMI categories, and geographical regions. The study was not powered to formally test treatment effects within individual subgroups; rather, the expanded sample size was selected pragmatically to support robust descriptive safety analyses across a heterogeneous population.

2.9. Statistical Methods and Data Analysis

Data of all participants who received at least one dose of study medication were used for analysis of safety and tolerability outcomes. All relevant statistical calculations were completed using SPSS software (Version 21, IBM Corporation, USA). The obtained analysis outcomes for ranking data and scores were tabulated as mean ± SD. To ensure adherence to best statistical practices, 95% Confidence Intervals (CI) were utilized in the study. All analyses were done using two‐sided tests and a p‐value of less than 0.05 was considered the threshold to claim statistical significance. For categorical variables, the number and percentage of subjects within each category (with category for missing data as needed) of the parameter were presented and p‐values were determined by Chi‐square test between the groups (ARE vs. PL).

3. Results

A total of 1286 individuals were screened, and 1002 were randomized to ARE (n = 498) or PL (n = 504). Although the initial efficacy‐based calculation required only 49 participants per group, a larger sample was enrolled to ensure adequate power for safety assessment and subgroup analyses. These minor differences reflected site‐specific recruitment rates rather than allocation imbalance. No participants were lost to follow‐up, and all randomized participants were included in the safety analysis. Attendance at the final study visit and inclusion in the safety analysis were verified through site‐level visit records, completed case report forms, and centralized database monitoring. All randomized participants completed the study and were included in the safety analysis set.

3.1. Demographic Profile of Participants and Baseline Data

Table 1 presents the demographic and baseline characteristics of participants enrolled in the study, comparing the PL group (n = 504) and the ARE group (n = 498). The participant flow through the study is presented in the CONSORT flow diagram (Figure 1; CONSORT Checklist: Table S1). This comparison ensures that both groups were balanced at baseline, allowing for a reliable assessment of the treatment effects.

TABLE 1.

Demography and baseline profile of the participants in the two groups.

	Placebo (n = 504)	ARE (n = 498)	Chi‐square test
	Mean (SD)	Mean (SD)
Age (yrs.)	39.89 (12.85)	39.28 (11.90)	0.787	0.432
BMI (kg/m2)	26.03 (3.58)	26.00 (3.51)	0.167	0.868

	No. (%)	No. (%)	χ 2	p
Age group
< 30 years	139 (27.6%)	120 (24.1%)	8.012	0.046
30 to < 40 years	112 (22.2%)	136 (27.3%)
40 to < 50 years	115 (22.8%)	132 (26.5%)
≥ 50 years	138 (27.4%)	110 (22.1%)
Positive medical history	44 (8.7%)	32 (6.4%)	1.898	0.168
Concomitant medication
None	460 (91.3%)	466 (93.6%)	4.809	0.440
One	25 (5.0%)	17 (3.4%)
Two	15 (3.0%)	11 (2.2%)
> 2 Drugs	4 (0.8%)	4 (0.8%)
Gender
Male	283 (56.2%)	267 (54.6%)	1.609	0.447
Female	221 (43.8%)	230 (45.2%)
Other	—	1 (0.2%)
Country of enrolment
India	450 (89.3%)	438 (88.0%)	—	—
USA	15 (3.0%)	20 (4.0%)
Africa	16 (3.2%)	16 (3.2%)
Portugal	7 (1.4%)	9 (1.8%)
Australia	16 (3.2%)	15 (3.0%)
BMI category (WHO global)
Underweight	4 (0.8%)	3 (0.6%)	0.528	0.913
Overweight	197 (39.4%)	198 (40.0%)
Pre‐obese	221 (44.2%)	223 (45.1%)
Obese	82 (16.4%)	74 (14.9%)

Note: Categorical variables were compared between groups using the Chi‐square test. Percentages are calculated based on the number of participants in each treatment group.

Abbreviations: ARE, Ashwagandha Root Extract; BMI, body mass index; WHO, World Health Organization.

FIGURE 1.

CONSORT flow diagram showing the disposition of participants included in the Safety Analysis Set. All randomized participants (ARE: n = 498; Placebo: n = 504) completed the study, with no losses to follow‐up. ARE, Ashwagandha Root Extract; CONSORT, Consolidated Standards of Reporting Trials.

3.2. Laboratory Investigations

Laboratory data were available for 892 participants (418 placebo and 474 ARE). The two groups were similar (p > 0.05) with respect to the baseline and week‐8 values for hematology (cell counts and hematocrit), and biochemical assessments (AST) (Table 2). Although more improvements (p > 0.05) were seen with ARE compared to PL for RBC count, hematocrit, hemoglobin, and AST, no clinically significant changes were reported for any of the participants in both ARE or PL.

TABLE 2.

Hematological and biochemical parameters.

b		Baseline			Week 8			p b (between group)
		Mean	SD	p a (within group)	Mean	SD	p a (within group)
Parameters
WBC count (cells/mm3)	Placebo	8946.38	1998.25	0.330	7343.71	1319.78	0.060	0.977
	ARE	8798.77	1972.14		7557.59	1448.81
RBC count (million/mm3)	Placebo	4.58	0.41	0.141	4.85	0.48	0.927	0.129
	ARE	4.63	0.47		4.84	0.49
Hematocrit (%)	Placebo	42.30	5.54	0.142	45.17	5.29	0.370	0.326
	ARE	43.59	15.95		45.54	4.68
Hemoglobin (gm/dL)	Placebo	13.53	1.86	0.384	13.66	1.66	0.649	0.222
	ARE	13.64	1.68		13.72	1.48
Platelet (×10,000 cells/mm3)	Placebo	3.02	0.78	0.320	3.13	0.78	0.994	0.054
	ARE	3.08	0.82		3.13	0.62
AST (IU/L)	Placebo	27.88	9.88	0.176	26.33	8.12	0.504	0.565
	ARE	29.08	13.43		25.91	7.37
ALT (IU/L)	Placebo	31.29	12.23	0.750	28.30	10.72	0.320	0.681
	ARE	31.66	18.23		29.14	10.22
Creatinine (mg/dL)	Placebo	0.81	0.20	0.416	0.83	0.20	0.579	0.353
	ARE	0.79	0.19		0.82	0.20

Note: Continuous variables are presented as mean ± standard deviation (SD).

Abbreviations: ALT, alanine aminotransferase; ARE, Ashwagandha Root Extract; AST, aspartate aminotransferase; gm/dL, grams per decilitre; IU/L, International units per litre; RBC, red blood cells; SD, standard deviation; WBC, white blood cells.

^a Within‐group comparisons between baseline and week 8 were performed using paired statistical tests.

^b Between group comparisons using repeated measures ANOVA for treatment as the main factor and time as a repeated measure.

3.3. AEs

No deaths or SAEs were reported in either group during the 8‐week treatment or follow‐up period. However, a total of 74 (7.4%) AEs were reported, with 46 events (9.2%) occurring in the PL group and 28 events (5.6%) in the ARE group (Table 3). The most commonly reported AEs were nausea, dry mouth, and headache. However, no SAEs/episodes were reported in the study period and during the follow‐up. Among those who did experience AEs, 33 participants (6.6%) in the PL group and 24 participants (4.8%) in the ARE group reported one AE. A smaller proportion of participants experienced two AEs, with five participants (1.0%) in the PL group and two participants (0.4%) in the ARE group. Only one participant (0.2%) in the PL group reported three AEs, while no participants in the ARE group experienced three or more (Table 3). There was no statistically significant difference in the distribution of AEs between the groups, indicating that Ashwagandha root extract administration was as well‐tolerated as the PL. There were no statistically significant differences in the distribution or frequency of AEs between the two groups (χ ² = 1.362, p = 0.850). The relative risk (RR) of experiencing at least one AE in the ARE group compared with PL was 0.67 (95% CI: 0.42–1.06), suggesting a numerically lower, though not statistically significant, AE incidence in the Ashwagandha group. These findings indicate that Ashwagandha root extract was well‐tolerated and comparable to a placebo in terms of safety profile, with no participants experiencing serious or treatment‐related adverse events.

TABLE 3.

Adverse events reported.

	Placebo (n = 504)		ARE (n = 498)		Total (n = 1002)		Chi‐square test
	No.	%	No.	%	No.	%	χ 2	p
Adverse event
Abdominal pain	0	—	1	0.2%	1	0.1%
Constipation	1	0.2%	0	—	1	0.1%
Diarrhea	2	0.4%	3	0.6%	5	0.5%
Dizziness	1	0.2%	0	—	1	0.1%
Drowsiness	2	0.4%	0	—	2	0.2%
Dry mouth	7	1.4%	7	1.4%	14	1.4%
Headache	11	2.2%	1	0.2%	12	1.2%
Insomnia	1	0.2%	1	0.2%	2	0.2%
Irritability	0	—	1	0.2%	1	0.1%
Irritable Bowel	0	—	1	0.2%	1	0.1%
Lack of appetite	1	0.2%	0	—	1	0.1%
Lack of energy	2	0.4%	0	—	2	0.2%
Nausea	16	3.2%	10	2.0%	26	2.6%
Palpitations	1	0.2%	0	—	1	0.1%
Restlessness	0	—	1	0.2%	1	0.1%
Somnolence	1	0.2%	0	—	1	0.1%
Vomiting	0	0.0%	2	0.4%	2	0.2%
Total events	46	9.2%	28	5.6%	74	7.4%
Total participants	39	7.8%	26	5.2%	65	6.5%	1.362	0.850

Note: Data are presented as number (%) of participants reporting each adverse event. No deaths, withdrawals due to adverse events, or serious adverse events were reported during the study. Statistical comparisons between groups were made using the Chi‐square test.

Abbreviations: ARE, Ashwagandha Root Extract; No., number of participants.

3.4. Global Assessment of Tolerability to Therapy (GATT)

No statistically significant (p = 0.487) difference in tolerability between the two groups, indicating that ARE was similarly well‐tolerated as the placebo. Most participants in both groups rated the treatment as either “Good” or “Excellent,” underscoring the favorable tolerability of the intervention (Figure 2).

FIGURE 2.

Global assessment of tolerability to therapy (GATT). ARE, Ashwagandha Root Extract.

4. Discussion

Ashwagandha ( Withania somnifera ) has long been recognized for its potential in stress management, with widespread use in traditional Ayurvedic medicine. More recently, modern clinical research has explored its adaptogenic properties, emphasizing its ability to modulate the body's response to stress, reduce anxiety, and improve general well‐being. However, like all herbal treatments, Ashwagandha root extract is not without its AEs, although these are typically mild and transient.

The present study was designed based on established clinical evidence on Ashwagandha in stress and anxiety management. The sample size was derived from Salve et al., reflecting similar population characteristics and outcome measures. An 8‐week intervention period was selected to capture meaningful physiological and psychological effects, while the use of validated tools such as the HAM‐A and GATT scales ensured robust evaluation of efficacy and tolerability.

All participants who received at least one dose of the study product were included in the safety analysis set, and treatment‐emergent adverse events were analyzed for this entire population. Laboratory investigations were evaluated in a subset of participants with complete data at each time point, as some samples were unavailable due to missed visits or insufficient sample volume for analysis. These instances were isolated and not associated with study discontinuation or treatment‐related adverse effects. No prespecified subgroup or sensitivity analyses were planned or conducted for the safety outcomes reported in this manuscript. Safety analyses were performed for the overall safety analysis set only, without stratification by demographic or clinical subgroups.

Several studies have previously reported AEs associated with Ashwagandha usage. For instance, a study by Chandrasekhar et al. (2012), investigating the efficacy of Ashwagandha in reducing stress, reported mild side effects such as drowsiness and decreased appetite among participants taking Ashwagandha extract compared to those receiving a placebo. Similarly, a study by Pratte et al. (2014) reviewing the effects of Ashwagandha found nausea, upset stomach, and diarrhea to be the most common AEs. Despite these occurrences, both studies noted that the side effects were generally self‐limiting and resolved without the need for discontinuation of therapy. However, the researchers concluded that the herb was generally well‐tolerated, with no severe or life‐threatening AEs reported. Additionally, there are a few more studies that reported AEs associated with Ashwagandha usage (Table S1).

Despite these AEs, Ashwagandha root extract has continued to provide therapeutic benefits for several conditions, reinforcing the value of further trials focusing on its safety profile. Such studies can provide critical insights into the herb's tolerability and help refine its use in clinical settings. Given the reports of AEs, this trial was conducted specifically to further understand and evaluate the safety profile of Ashwagandha.

The current study evaluated the safety and tolerability of ARE in 1002 participants over an eight‐week period. The incidence of AEs in the Ashwagandha. This difference, though not statistically significant, may reflect inter‐individual variability, reporting bias, or the mild adaptogenic and stress‐modulating properties of Ashwagandha, which could contribute to better overall well‐being and symptom perception. The most frequently reported AEs in the Ashwagandha group were nausea (2.0%), dry mouth (1.4%), and headache (0.2%), all of which were mild to moderate in severity and transient in nature. Importantly, no SAEs, defined as those resulting in death, hospitalization, disability, or requiring medical intervention, were reported in either group.

The laboratory data further support the overall safety of Ashwagandha root extract. Across various hematological and biochemical parameters, no statistically or clinically significant differences were observed between the ARE and PL groups, either at baseline or after 8 weeks of intervention. Parameters such as WBC count, hemoglobin, hematocrit, platelet count, creatinine, AST, and ALT remained within normal physiological ranges in both groups. Although a slight reduction in mean AST and ALT levels was observed in the Ashwagandha group, these changes were not statistically or clinically significant (p > 0.05) and therefore cannot be interpreted as indicative of a hepatoprotective effect. Overall, the findings suggest that short‐term Ashwagandha supplementation does not adversely affect key hematological or biochemical indices.

The GATT results indicate that 88.2% of participants in the ARE group rated their experience as “excellent” or “good,” which is comparable to the 89.1% rating for the placebo group. The statistical analysis (p = 0.487) confirmed no significant difference in tolerability between the two groups, suggesting that ARE is as well‐tolerated as a placebo.

Taken together, the findings of this study demonstrate that short‐term supplementation with Ashwagandha root extract (ARE, 600 mg/day) is generally safe and well‐tolerated in adults with stress and anxiety, with no SAEs reported. While mild AEs such as nausea, dry mouth, and headache were observed, their frequency was comparable to or lower than that of the PL group, indicating a favorable safety profile. These results are consistent with previous randomized controlled trials and systematic reviews reporting that Ashwagandha is well‐tolerated when administered within therapeutic doses. The present study adds to this body of evidence by providing multicentric data across diverse populations.

The study has certain limitations, including its relatively short duration of 8 weeks, which limits the assessment of long‐term safety outcomes. Incomplete paired laboratory data for all participants and reliance on standard biochemical parameters without inclusion of advanced biomarkers may restrict the depth of safety evaluation. A key limitation of this study is that the primary statistical analysis focused on within‐group comparisons from baseline rather than direct between‐group comparisons. As a result, the findings should be interpreted as changes over time within each group, and causal inferences regarding comparative efficacy between the intervention and placebo groups should be made with caution. Furthermore, the limited representation from non‐Indian populations may affect the generalizability of the findings across diverse ethnic groups.

5. Conclusion

In conclusion, the current study provides evidence that KSM‐66 ARE is a safe and well‐tolerated intervention for adults experiencing borderline to moderate symptoms of stress and anxiety. The absence of SAEs and the minimal incidence of mild side effects underscore Ashwagandha root extract's favorable safety profile, further supported by high tolerability ratings from participants. These findings align with previous research on the safety of Ashwagandha root extract. However, as this study primarily reports safety outcomes and does not evaluate comparative efficacy, no conclusions regarding therapeutic effectiveness or treatment equivalence can be drawn. Further well‐designed, adequately powered trials assessing efficacy and long‐term outcomes are warranted.

Author Contributions

Jose Parraca: conceptualization, writing – review and editing, writing – original draft. Ketan Pakhale: conceptualization, investigation, data curation, writing – review and editing, resources. Jaising Salve: conceptualization, investigation, resources. John Ademola: investigation, resources, writing – review and editing, formal analysis. Deepak Langade: writing – original draft, writing – review and editing, formal analysis.

Funding

The study was supported by Shri Kartikeya Pharma, Hyderabad, India.

Ethics Statement

The study at D. Y. Patil Medical College and Hospital, Navi Mumbai, under the supervision of Dr. Sanjiv Kale, was approved by the Institutional Ethics Committee, D. Y. Patil Medical College, Hospital and Research Center, Navi Mumbai (DYP/IEC/01‐003‐A/2020) on 20 February 2020. The study at Prakruti Care Hospital, led by Dr. Jaising Salve, received approval from the Institutional Ethics Committee, D. Y. Patil Medical College, Hospital and Research Center, Navi Mumbai (DYP/IEC/01‐003‐B/2020) on 20 February 2020. The study conducted at Metabol by Dr. Ketan Pakhale was approved by the Institutional Ethics Committee, D. Y. Patil Medical College, Hospital and Research Center, Navi Mumbai (DYP/IEC/01‐003‐D/2020) on 20 February 2020. Ethical approval for the study conducted at Prime Hospital under Dr. Jignesh Prajapati was obtained from the Institutional Ethics Committee (IEC) on 25 May 2021 (Protocol No.: KSM‐66/PMS/2018/09). The study conducted at BLDE (Deemed to be University) under the supervision of Dr. Santosh Ramdurg received ethical approval from the Institutional Ethics Committee, BLDE (Deemed to be University), on 27 December 2019 (EC No.: BLDE (DU)/IEC/418/2019‐20). The study under Dr. Adrian Lopresti was approved by the National Institute of Integrative Medicine Human Research Ethics Committee (NIIM HREC) (EC00436) on 26 May 2020 (Reference No.: 0063E_2020). The study conducted under the supervision of Dr. Jose received approval from the Institutional Ethics Committee, Universidade de Évora, on 14 December 2022 (Document No.: 22103). The study at Prajakta Clinic, Ghatkopar East, led by Dr. Sahiba Singh, was approved by the Institutional Ethics Committee, D. Y. Patil Medical College, Hospital and Research Center, Navi Mumbai (DYP/IEC/003‐E/2020) on 26 September 2022. The study at Teerthanker Mahaveer Medical College & Research Center, supervised by Dr. Prerana Gupta, was approved by the Institutional Ethics Committee, Teerthanker Mahaveer University (TMU), Moradabad (TMU/IEC/2021‐22/71) on 23 November 2022. The study at Bharati Vidyapeeth Medical College & Hospital, conducted by Dr. Priti Pravin Dhande, was approved by the B. V. University Institutional Ethics Committee (EC/NEW/INST/2022/MH/0150) on 14 February 2023. The study at MGM Medical College & Hospital, under Dr. Prakash Khandelwal, was approved by the Ethics Committee for Research on Human Subjects (MGMIHS/R&D/ECRHS/03/2023/179) on 22 May 2023. The study conducted at CLINI‐TON Multi speciality Clinic, under Dr. B. L. Prajapati, was approved by the ACH Ethics Committee on 15 July 2023 (Protocol No.: KSM66/PMS/2018/09). The study at SGD Super speciality Clinic, supervised by Dr. Sanjay Sharma, received approval from the ACH Ethics Committee on 15 July 2023 (Protocol No.: KSM66/PMS/2018/09).

Conflicts of Interest

The authors declare no conflicts of interest.

Supporting information

Table S1: Reported adverse events of Ashwagandha.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.