Standardized Holy Basil Extract (Holixer™, 250 mg/day) Improves Stress and Sleep Outcomes and Reduces Cortisol Reactivity in Stressed Adults: Evidence from an 8-Week RCT

Written by Keely Puchalski, ND. Results from this trial suggest that 8 weeks of supplementation with a standardized Ocimum tenuiflorum extract (Holixer™) at 250 mg/day reduced perceived stress and improved subjective sleep quality compared to placebo in adults experiencing stress and poor sleep.

woman lying down on sofa with headache feelingOcimum tenuiflorum (Holy Basil, Tulsi) is an Ayurvedic adaptogen whose active constituents—eugenol, ursolic acid, ocimumosides, and ocimarin—demonstrate preclinical activity at neuroendocrine stress nodes: inhibiting corticotropin-releasing hormone receptor 1 (CRHR1), suppressing 11β-hydroxysteroid dehydrogenase-1 (11β-HSD1, which converts cortisone to active cortisol), and reducing catechol-O-methyltransferase (COMT) activity.1–7 These effects modulate both the hypothalamic-pituitary-adrenal (HPA) axis and the sympathoadrenal medullary (SAM) system. A 2017 systematic review of 24 clinical trials supported Ocimum tenuiflorum’s adaptogenic role but called for more rigorous evidence.8 Prior placebo-controlled trials showed anti-stress effects at 1,000–1,200 mg/day using different extracts;9,10 but no trials had examined sleep outcomes. Because sustained hyperarousal is implicated in insomnia pathophysiology,11 the authors hypothesized HPA/SAM modulation might also benefit sleep. This trial evaluated a standardized Ocimum tenuiflorum extract (Holixer™) at 250 mg/day in moderate-to-severely stressed adults with concurrent sleep difficulties.

This was an 8-week, randomized, double-blind, placebo-controlled trial (n=100; 50/group). Eligible participants were men and women aged 18–65 (BMI 18.5–35 kg/m²) with >1 month of stress (PSS ≥14), concurrent sleep complaints, and no psychiatric diagnosis or PHQ-4 >8. Holixer™ (two capsules twice daily = 250 mg/day) is a GMP-manufactured hydroalcoholic extract standardized to ≥5% w/w Ocimum Bioactive Complex. Placebo was appearance-and odor-matched. Adherence: 94% of completers took >80% of capsules; blinding was adequate.

Primary outcome: Perceived Stress Scale (PSS; 0–40, assessed every 2 weeks), a validated self-report measure of perceived life stress.12 Secondary outcomes included the Athens Insomnia Scale (AIS; an 8-item validated insomnia severity scale16), RSQ-W (restorative sleep17), POMS-A (mood15), PROMIS-29 (health-related quality of life18), and Fitbit Charge 4 objective sleep metrics. At week 8, the Maastricht Acute Stress Test (MAST)—a validated 12-minute combined physical/cognitive stressor test22,23—assessed reactivity via salivary cortisol, salivary alpha-amylase (sAA), blood pressure, and VAS stress ratings. Hair cortisol (0–2 cm from scalp) estimated chronic HPA activity after 8 weeks 24,25 Analyses used Generalized Linear Mixed Models (GLMM) with ITT principles, assessing time × group interaction as the primary inferential test and covarying for age, sex, and BMI (α=0.05).

Key Findings:

  • PSS (primary outcome): Significant time × group interaction (p=0.003). Ocimum: 37% reduction from baseline; placebo: 19%. Mean reductions 8.02 vs. 4.28 points.
  • AIS (insomnia severity): Significant time × group interaction (p=0.025). Ocimum: 48% reduction; placebo: 27%. Between-group difference at week 8 (p=0.030); mean reductions 5.42 vs. 3.23 points.
  • MAST (week 8 only): At week 8, the Ocimum group showed consistently lower physiological arousal across all MAST time points compared to placebo, with significant between-group differences in salivary cortisol (p=0.001), sAA (p=0.001), systolic BP (p=0.010), diastolic BP (p=0.025), and VAS stress ratings (p<0.001); pulse rate did not differ (p=0.224). Both groups mounted and recovered from the stressor in a similar pattern (time × group interactions non-significant for all measures).
  • Hair cortisol (week 8 only): Significantly lower in Ocimum vs. placebo at week 8 (269.68 vs. 789.89 pg/50mg; p=0.025).
  • No statistically significant between-group differences were observed for RSQ-W (p=0.984), POMS-A total mood disturbance (p=0.695), any PROMIS-29 subscale, or any Fitbit sleep metric (total sleep time p=0.971, sleep efficiency p=0.516, time in bed p=0.816).
  • No serious adverse events were reported. Minor effects were comparable between groups (12 Ocimum vs. 10 placebo), most commonly digestive disturbances (5/group). Two withdrawals were possibly supplement-related: agitation in the Ocimum group and nausea in the placebo group. No adverse events were reported in 83% of participants.

Two observations stand out beyond what the authors discuss. Both groups improved most sharply on PSS and AIS by week 2, but only the Ocimum group continued improving through week 8—while placebo PSS actually ticked upward from week 6 to week 8, suggesting a potentially cumulative benefit that a longer trial could confirm. The MAST data also reveal that the Ocimum group entered the stress challenge with lower baseline arousal and showed a more blunted cortisol recovery curve, pointing to a shift in basal HPA tone rather than acute reactivity buffering alone—arguably one of the trial’s most mechanistically compelling findings.

A couple of limitations temper the interpretation of the cortisol and sleep findings. Both MAST physiological data and hair cortisol were collected only at week 8 without pre-treatment baselines, meaning between-group differences reflect post-treatment snapshots rather than confirmed within-subject change. The hair cortisol model was further undermined by unexpected between-group differences in the presumed pre-treatment hair segment, and the placebo group showed extreme within-group variability (mean 790 pg/50mg; 95% CI 229–1,408), raising questions about measurement reliability independent of the missing baseline. Together, these issues make causal attribution of the cortisol finding difficult. On sleep, the significant AIS improvement was not corroborated by any Fitbit metric, and Fitbit is known (as was acknowledged by the authors) to overestimate sleep relative to polysomnography.¹⁹⁻²¹ Cross-study dose comparisons with prior Ocimum tenuiflorum trials (600–1,200 mg/day of differently standardized extracts) are also unreliable without pharmacokinetic data. Industry funding and investigator honoraria, though declared non-influential, warrant acknowledgment.

Overall, this well-designed trial adds meaningful evidence for Holixer™ as a lower-dose standardized adaptogen with convergent effects on perceived stress, insomnia severity, and physiological stress reactivity. Integrative practitioners may find it relevant for non-clinical adults managing moderate, subacute, or chronic stress, with the important caveat that findings do not apply to diagnosed anxiety, mood, or sleep disorders. Pre-treatment cortisol sampling, a baseline MAST, longer duration, polysomnography, and independent replication remain the next necessary steps.

Source: Lopresti AL, Smith SJ, Metse AP, Drummond PD. A randomized, double-blind, placebo-controlled trial investigating the effects of an Ocimum tenuiflorum (Holy Basil) extract (Holixer™) on stress, mood, and sleep in adults experiencing stress. Front Nutr. 2022;9:965130. doi:10.3389/fnut.2022.965130

© 2022 Lopresti, Smith, Metse and Drummond. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY).

Click here to read the full text study.

Posted May 29, 2026.

Keely Puchalski, ND, is a licensed naturopathic physician and natural products expert with a clinical focus on mental health. She earned her ND from Sonoran University of Health Sciences (formerly Southwest College of Naturopathic Medicine) in 2020. Dr. Puchalski has conducted original research in botanical medicine, with discoveries leading to multiple patents and high-impact journal publications. She has authored eight peer-reviewed papers and presented her work at national conferences, webinars, and educational events.

She is the co-founder of Restored Counseling & Wellness Center in Gilbert, AZ, where she leads a collaborative team of therapists and naturopathic doctors dedicated to integrative mental health care:  https://restoredcw.com.

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