Zenroot® (Low-Dose Bioavailable Ashwagandha Root Extract — OmniActive)

Withania somnifera
Evidence Level
Strong
2 Clinical Trials
6 Documented Benefits
4/5 Evidence Score

Zenroot® is OmniActive's root-only ashwagandha (Withania somnifera) extract — standardized to 1.5% withanolides using USP methodology, with enhanced bioavailability enabling efficacy at an unusually low 125 mg/day dose. Root-only positioning matters: regulatory pressure on ashwagandha in Europe has focused on the leaf/aerial parts (higher withaferin A content), making root-only extracts the preferred form for long-term safety. Two peer-reviewed trials support the 125 mg dose: a bioavailability crossover showing Zenroot 125 mg produced 2.1× higher absorption than a 600 mg 5%-withanolide reference and 1.3× higher than a 500 mg 10% reference; and a 12-week RCT in adults with mild-to-moderate stress showing reduced Perceived Stress Scale scores, improved sleep quality, and gains in mood and occasional anxiety vs placebo. Honest framing: low-dose efficacy backed by recent solid trials; the ashwagandha category has substantial class evidence and Zenroot offers a competitive bioavailability-enhanced low-dose option suitable for gummies and functional beverages.

Studied Dose 125 mg/day.
Active Compound Withania somnifera root-only extract standardized to 1.5% total withanolides (USP method); root-only minimizes withaferin A.

Benefits

Stress reduction in under 30 days

12-week randomized double-blind placebo-controlled trial in adults with mild-to-moderate stress. 125 mg/day Zenroot produced a significant decrease in Perceived Stress Scale scores in less than 30 days vs placebo, supported by objective skin-response measurement alongside the subjective scale.

Sleep quality improvement (12-week trial)

The same trial documented statistically significant improvements in sleep quality by day 28 vs both baseline and placebo, sustained through the 12-week protocol. Sleep mechanism consistent with ashwagandha's broader adaptogenic profile — reducing nighttime cortisol and supporting calmer sleep onset.

2.1× higher bioavailability vs 600 mg 5% reference

Randomized double-blind single-dose crossover bioavailability study in healthy adults under fasting. 125 mg Zenroot achieved 2.1× higher total withanolide plasma absorption vs a 600 mg ashwagandha 5%-withanolide reference, and 1.3× higher vs a 500 mg 10% reference. Established the low-dose efficacy rationale measurably.

Mood and occasional anxiety improvements

12-week trial outcomes included statistically significant improvements in mood state and severity of occasional anxiety symptoms vs placebo. Consistent with ashwagandha's traditional Ayurvedic use as a calming adaptogen. Mechanism likely involves HPA axis modulation and GABAergic activity.

Root-only sourcing for regulatory safety

European regulators have flagged concerns about ashwagandha aerial parts (leaves), which have higher withaferin A content potentially associated with rare hepatic adverse events. Root-only sourcing (the traditional Ayurvedic preparation) reduces this regulatory and safety concern, making Zenroot more suitable for European markets and long-term use.

Low-dose convenience for novel formats

The 125 mg low-dose advantage enables formulation in gummies, functional shots, ready-to-drink beverages, and other formats where higher mg doses wouldn't fit. Competing ashwagandha extracts at 500-600 mg are challenging for these formats. Excellent organoleptic profile (bland taste, dissolution) supports beverage applications.

Mechanism of action

1

HPA axis modulation

Ashwagandha withanolides modulate the hypothalamic-pituitary-adrenal axis, reducing baseline cortisol and dampening cortisol response to stressors. Multiple ashwagandha trials show 15-30% reductions in serum cortisol after 8-12 weeks. The HPA modulation underlies both stress and sleep benefits.

2

GABAergic activity

Withanolides bind to GABA-A receptors with modulatory effects similar in kind (but milder) to benzodiazepines. This GABAergic activity contributes to the calming nootropic profile — anxiolytic effects without sedation at typical clinical doses.

3

Enhanced bioavailability (Zenroot-specific)

OmniActive's proprietary extraction and standardization process delivers withanolides in a form with improved absorption — documented as 2.1× higher plasma withanolide exposure vs 600 mg 5%-withanolide reference. The mechanism appears to involve the natural withanolide profile and matrix rather than added bioavailability enhancers.

4

Antioxidant and anti-inflammatory effects

Withanolides have direct antioxidant activity and modulate inflammatory pathways (NF-κB, NLRP3 inflammasome). Chronic stress drives oxidative stress and inflammation; ashwagandha's antioxidant/anti-inflammatory effects complement its HPA axis modulation for broader stress resilience support.

Clinical trials

1
Zenroot Bioavailability Study — Advances in

Randomized double-blind single-dose crossover comparative oral bioavailability study in 20 healthy adults under fasting conditions.

20 healthy adults

Randomized double-blind single-dose crossover comparative oral bioavailability study in 20 healthy adults under fasting conditions. Three arms: Zenroot 125 mg (1.5% withanolides), reference 600 mg (5% withanolides), reference 500 mg (10% withanolides). Plasma withanolide measurements at multiple time points over 24 hours. Outcome: Zenroot 125 mg achieved 2.1× higher absorption than the 600 mg 5% reference and 1.3× higher than the 500 mg 10% reference.

2
Zenroot for Stress, Sleep, Mood, Anxiety — Advances in

12-week randomized double-blind placebo-controlled trial in 90 adults aged 18-55 with mild-to-moderate stress. Intervention: 125 mg/day Zenroot or placebo.

90 adults aged 18-55 with mild-to-moderate stress

12-week randomized double-blind placebo-controlled trial in 90 adults aged 18-55 with mild-to-moderate stress. Intervention: 125 mg/day Zenroot or placebo. Outcomes: significant decrease in Perceived Stress Scale and Mindfield eSense Skin Response in under 30 days; sleep quality improvement by day 28 vs baseline and placebo; improvements in mood state and severity of occasional anxiety symptoms over 12 weeks. Conducted at Bengaluru Neuro Center, Santosh Hospital.

Side effects and drug interactions

Common Potential side effects

Excellent tolerability profile in both 2025 trials.
Mild GI side effects rare.
Root-only sourcing minimizes withaferin A content and theoretical hepatic concerns associated with whole-plant or leaf-containing ashwagandha extracts (very rare reports of ashwagandha-associated hepatitis).
Mild sedation in some users — consistent with the calming adaptogenic profile.
Possible mild thyroid hormone elevation (ashwagandha may modestly increase T3/T4) — relevant for hyperthyroid patients to monitor.

Important Drug interactions

Sedatives and anxiolytics (benzodiazepines, barbiturates, z-drugs) — additive sedation; use caution.
Thyroid medications — ashwagandha may increase T3/T4; monitor and adjust thyroid medication dose if needed.
Immunosuppressants — ashwagandha may stimulate immune function; theoretical interaction with immunosuppressive therapy; consult prescriber.
Antidiabetic medications — mild hypoglycemic effects possible; monitor blood glucose.
Antihypertensives — mild additive BP-lowering possible.
Pregnancy and lactation — avoid. Ashwagandha is traditionally contraindicated in pregnancy due to possible abortifacient effects in animal studies.

Frequently asked questions about Zenroot® (Low-Dose Bioavailable Ashwagandha Root Extract — OmniActive)

What is Zenroot?

Zenroot® is OmniActive's root-only ashwagandha (Withania somnifera) extract — standardized to 1.5% withanolides using USP methodology, with enhanced bioavailability enabling efficacy at an unusually low 125 mg/day dose.

What is Zenroot used for?

Zenroot is researched primarily for Stress & Anxiety, Sleep Health, and Cognitive. 12-week randomized double-blind placebo-controlled trial in adults with mild-to-moderate stress. 125 mg/day Zenroot produced a significant decrease in Perceived Stress Scale scores in less than 30 days vs placebo, supported by objective ski…

What is the recommended dosage of Zenroot?

The clinically studied dose is 125 mg/day. Always follow the product label and check with a healthcare provider for personal advice.

Is Zenroot safe, and does it have side effects?

For most healthy adults, Zenroot is well tolerated at studied doses. Reported effects can include: Excellent tolerability profile in both 2025 trials. Mild GI side effects rare. It may also interact with some medications. Zenroot is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Zenroot interact with any medications?

Possible interactions include: Sedatives and anxiolytics (benzodiazepines, barbiturates, z-drugs) — additive sedation; use caution. Thyroid medications — ashwagandha may increase T3/T4; monitor and adjust thyroid medication dose if needed. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Zenroot?

NutraSmarts rates the evidence for Zenroot as Strong (4 out of 5). It is backed by 2 clinical trials and 4 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(4 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Majeed M, Nagabhushanam K, Mundkur L. A standardized Ashwagandha root extract alleviates stress, anxiety, and improves quality of life in healthy adults by modulating stress hormones: Results from a randomized, double-blind, placebo-controlled study. Medicine (Baltimore). 2023;102(41):e35521. doi: 10.1097/MD.0000000000035521.PubMedUsed to support: Small (n=130) industry-funded RCT reporting that ashwagandha root extract lowered perceived stress and serum cortisol versus placebo, backing the stress/anxiety and cortisol claim.
  2. Arumugam V, Vijayakumar V, Balakrishnan A, B Bhandari R, Boopalan D, Ponnurangam R, et al. Effects of Ashwagandha (Withania Somnifera) on stress and anxiety: A systematic review and meta-analysis. Explore (NY). 2024;20(6):103062. doi: 10.1016/j.explore.2024.103062.PubMedUsed to support: Systematic review/meta-analysis pooling small RCTs that found ashwagandha reduced stress and anxiety scores versus placebo, supporting the stress claim while noting most included trials are small and industry-funded.
  3. Cheah KL, Norhayati MN, Husniati Yaacob L, Abdul Rahman R. Effect of Ashwagandha (Withania somnifera) extract on sleep: A systematic review and meta-analysis. PLoS One. 2021;16(9):e0257843. doi: 10.1371/journal.pone.0257843.PubMedUsed to support: Meta-analysis of 5 small RCTs finding ashwagandha modestly improved overall sleep quality, sleep onset latency, and sleep efficiency versus placebo, backing the sleep claim (effects small; several trials industry-funded).
  4. Leonard M, Dickerson B, Estes L, Gonzalez DE, Jenkins V, Johnson S, et al. Acute and Repeated Ashwagandha Supplementation Improves Markers of Cognitive Function and Mood. Nutrients. 2024;16(12):1813. doi: 10.3390/nu16121813.PubMedUsed to support: Small randomized placebo-controlled trial reporting acute and repeated ashwagandha improved some cognitive-performance and mood markers, supporting the cognition claim (small sample, industry-supported).