Holy Basil Extract

Clinical trials and systematic reviews show Holy basil (Tulsi, Ocimum tenuiflorum / O. sanctum) can reduce perceived stress and some anxiety symptoms and lower cortisol in adults. Most positive trials used standardized extracts (capsules) at doses ranging from ~250 mg/day up to ~1,200 mg/day for 6–8 weeks. Evidence quality is moderate (several randomized controlled trials exist but not yet large, long-term safety trials). Always check with your clinician before starting, especially if pregnant, breastfeeding, on blood thinners, or diabetic. Frontiers

Multiple preclinical and clinical lines of evidence suggest Holy basil can reduce stress/anxiety because it:

• Modulates the stress response / HPA axis — trials report reductions in cortisol (including hair cortisol, a longer-term marker) after 6–8 weeks, supporting dampening of chronic stress physiology. Frontiers
• Buffers acute stress reactivity — in an experimental stress test (MAST), Tulsi reduced salivary cortisol, salivary amylase and blood-pressure responses compared with placebo. This shows reduced physiological reactivity to stressors. Frontiers
• Contains multiple bioactive phytochemicals (eugenol, rosmarinic acid, ursolic acid, β-caryophyllene, carvacrol, various flavonoids and triterpenes) with antioxidant, anti-inflammatory and neuromodulatory effects — plausible routes by which mood/anxiety can improve. Frontiers
• May influence neurotransmitters — animal studies show modulation of monoamines (serotonin, dopamine) and effects on GABAergic pathways in stress models, which are mechanisms shared by many anxiolytics. PLOS

Forms used in clinical research

• Standardized oral extracts in capsules (most clinical trials). These are preferred in research because dose and active content are controlled (product names in trials include Holixer™, OciBest®, etc.). Frontiers+1
• Dried leaf tea and fresh leaves are traditionally used in Ayurveda; less standardized and lower dose than extracts. Clinical evidence generally uses concentrated extracts rather than tea. Ohio State Health

Doses and regimens actually used in human trials

• 250 mg/day (125 mg twice daily) of a standardized Holixer™ extract for 8 weeks — improved perceived stress, insomnia scores, and lowered hair cortisol and stress reactivity vs placebo. (Randomized, double-blind trial.) Frontiers
• 1,000–1,200 mg/day (total daily) of other standardized extracts for 6 weeks — reduced stress symptoms in randomized/controlled trials. PLOS+1
• 500 mg twice daily (1,000 mg/day) oral extract for 60 days — reported improvements in patients with generalized anxiety disorder in a hospital-based (open) trial. (This trial lacked placebo control; interpret cautiously.) ResearchGate+1
• Lower doses (e.g., 300 mg/day) have been used in cognition studies (30 days). Drugs.com

Practical, evidence-based guidance you can follow (if considering use)

Prefer a standardized extract/capsule from a reputable manufacturer (research used standardized products such as Holixer™, OciBest®). Standardized extracts are easier to match to studied doses. Frontiers+1

Dose range to consider (based on trials):

• For mild–moderate stress/anxiety: ~250 mg/day (e.g., 125 mg twice daily) was effective in an RCT; higher doses (500–1,200 mg/day) were used in other trials with positive effects. Start at a lower end and titrate if needed under clinician supervision. Frontiers

Duration: most positive trials ran 6–8 weeks; benefits were assessed at 4–8 weeks. Expect to evaluate effect only after several weeks. Frontiers

When to take: in trials capsules were given once or twice daily with food. Follow the product label or trial protocol. Frontiers

Avoid relying on tea for therapeutic doses used in trials; tea/fresh leaves are safe dietary items but usually provide much lower active dose than standardized extracts used in clinical studies. Ohio State Health

If you’re using it alongside medications: consult your clinician — see the safety/interaction section below. (Important: do not stop prescribed anxiolytics or antidepressants without medical supervision.)

Lopresti AL et al., 2022 — Randomized, double-blind, placebo-controlled trial (Holixer™), 125 mg twice daily (250 mg/day) for 8 weeks — improved Perceived Stress Scale, insomnia ratings, lowered hair cortisol and reduced physiological stress reactivity (MAST). (Frontiers in Nutrition, 2022). Frontiers

Link: (full text) Frontiers article. Frontiers

PLOS One / Holixer review & mechanistic paper — covers Holixer™ and possible HPA-axis modulation and references prior trials. Useful for mechanism context. PLOS

Saxena RC et al., 2012 — OciBest® extract, randomized double-blind placebo-controlled study (1200 mg/day, 6 weeks) — reported reductions in stress-related symptoms. (Evidence-Based Complementary and Alternative Medicine, 2012). Semantic Scholar

Bhattacharyya D et al., 2008 — hospital-based trial on generalized anxiety disorder (35 patients), 500 mg twice daily for 60 days — saw improvements in anxiety/depression scores (open, non-placebo controlled). Use cautiously (non-placebo design). (Nepal Med Coll J; PMID: 19253862). ResearchGate

Systematic review: “The Clinical Efficacy and Safety of Tulsi in Humans: A Systematic Review” (2017) — summarizes many human trials across metabolic, immune and neurocognitive outcomes and concludes evidence is promising but calls for more rigorous trials. Wiley Online Library

Adaptogen / cortisol reviews — meta-analyses and reviews of adaptogenic herbs (including Tulsi) describe cortisol reduction and stress-buffering effects; useful for broader context. ScienceDirect

Authoritative safety and patient-facing summaries: WebMD, Ohio State University Wexner Medical Center, Drugs.com — these summarize uses, doses in studies, interactions and warnings. Useful for counseling and safety checks. WebMD