Ashwagandha formulation ZEN 1.5 and withanolide levels in blood
What it found
In 18 healthy adults, a single 125 mg dose of a new ashwagandha extract (ZEN 1.5) put more withanolides into the blood than single doses of two standard extracts at 600 mg and 500 mg.
The authors say the new extract was well tolerated.
What they found
Studies in people
Withanolides in blood
ZEN 1.5 at 125 mg gave higher total withanolide levels in blood at all time points except 12 and 24 hours compared with ASH 5 at 600 mg. It also gave higher levels at 0.25, 1, 2, 3 and 4 hours compared with ASH 10 at 500 mg.
Amount reaching blood
ZEN 1.5 at 125 mg delivered 2.1 times more total withanolides into the blood than ASH 5 at 600 mg, and 1.3 times more than ASH 10 at 500 mg. After adjusting for dose, ZEN 1.5 showed much higher relative absorption than both reference products.
Time to peak and clearance
ZEN 1.5 took a similar time to reach peak blood levels as ASH 5, and 33% longer than ASH 10. ZEN 1.5 cleared from the blood faster than both ASH 5 and ASH 10.
Side effects
No adverse events happened during the study. Four mild events were reported after the study finished, including one low hemoglobin, one high white blood cell count, and one low hemoglobin with low red blood cells. The lead investigator judged these unrelated to the products.
How it was done
The authors say the amount of ashwagandha's active compounds that actually reaches the blood matters for whether the supplement can have biological effects. They wanted to compare their new formulation against widely used commercial extracts.
They gave 20 healthy adults single doses of three ashwagandha products in a random order, with blood samples taken over 24 hours. The products were ZEN 1.5 at 125 mg, ASH 5 at 600 mg, and ASH 10 at 500 mg. Eighteen people completed the study.
What it can’t tell you
- This study measured blood levels of withanolides, not health effects like stress or anxiety.
- It used a single dose in healthy adults, so it cannot show what happens with long-term use or in people with health conditions.
Who paid
- Conflicts
- Declarations. Conflict of Interest: Muralidhara Padigaru, Abhijeet Morde, and Paras Patni are employees of OmniActive Health Technologies Limited. R Abiraamasundari, L Vijayakrishnan, Lincy Joshua, and Jestin V. Thomas declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Ethical Approval: Institutional ethics approval was obtained from ‘The Research Ethics Committee’ Coimbatore, India. This study was conducted in compliance with the ethical principles originating in or derived from the Declaration of Helsinki and in compliance with the International Conference on Harmonization (ICH), Good Clinical Practice (GCP) Guidelines, as well as in strict compliance with the “The New Drugs and Clinical Trial Rules- 2019”, the Ministry of Health and Family Welfare and the Government of India at all stages of the trial for adherence to protocol and compliance with ethical and regulatory guidelines. Voluntary consent was obtained in written from all the study participants before commencing any study related activities. The EC was duly apprised of the progress and updates of the trial at regular intervals as per prescribed guidelines.
The paper
- Title
- Superior Bioavailability of a Novel 1.5% Ashwagandha Formulation (Zenroot™): A Randomized, Double-Blind, Single-Dose, Comparative, Oral Bioavailability Study in Healthy Adults
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Ramapalaniappan A, Loganathan V, Morde A, et al (2025). Superior Bioavailability of a Novel 1.5% Ashwagandha Formulation (Zenroot™): A Randomized, Double-Blind, Single-Dose, Comparative, Oral Bioavailability Study in Healthy Adults. Advances in therapy. doi:10.1007/s12325-025-03292-7Free full textPubMed 40748423DOI
Summary written 29 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error