Withaferin A (WFA) in Oncology
A detailed overview of withaferin A in oncology, including mechanisms, evidence, pharmacokinetics, safety, dosing, and sourcing.
Withaferin A (WFA) is a steroidal lactone from Withania somnifera (Ashwagandha). It is the best-characterised direct anticancer compound in the plant. It does not require microbiome conversion or metabolic activation.
WFA matters in oncology because it binds covalently to selected cysteine residues on target proteins. That gives it an unusual combination of potency, multi-pathway reach, and mechanistic specificity. In preclinical models, it blocks autophagic flux at the lysosomal step, suppresses ER-α in ER-positive breast cancer, destabilises HSP90 client proteins, disassembles vimentin, targets cancer stem cell populations, and reshapes parts of the tumour immune microenvironment.
The strongest evidence remains preclinical. Human efficacy data for purified WFA is still absent. The clinical signal is early and should be interpreted that way.
At a glance
Best-established mechanism: autophagy blockade at the lysosomal degradation step through impaired cathepsin D maturation and lysosomal dysfunction.
Most important translational advantage: a short human half-life of roughly
2.9–10.3 hours, which makes true pulse scheduling feasible.Main formulation issue: unformulated oral WFA has very low bioavailability.
Clinical position: adjunctive and investigational. It is not standard of care.
Main evidence gap: no completed human efficacy trial of purified or liposomal WFA against a defined oncology endpoint.
IMPORTANT: Please do not assume that any “ashwagandha” supplement will provide oncology‑relevant WFA exposure. This page was created to highlight Withaferin A‑focused targets, and specialised WFA‑standardised leaf extracts are required, not general ashwagandha root products. For support in sourcing see the Sourcing Quality page within this WFA in Oncology Hub.
Why oncology researchers focus on WFA
Several features make WFA stand out from most natural compounds discussed in cancer care.
First, it is not a weak single-target phytochemical. It hits several resistance-relevant pathways at once, including autophagy, EMT, cancer stem cell survival, HSP90-dependent signalling, and inflammatory survival networks.
Second, its covalent protein binding is unusual. WFA contains two electrophilic sites — the C-5, C-6 epoxide and the C-1, C-2-unsaturated enone — that enable selective cysteine targeting on proteins such as vimentin and other signalling components.
Third, the plant part matters. Leaves contain substantially more WFA than roots. Standard root extracts used for stress and sleep support are not equivalent to leaf-derived WFA-standardised formulations.
Fourth, its pharmacology is more pulse-friendly than hydroxychloroquine. WFA clears on an hours scale. Hydroxychloroquine accumulates in tissues and has a terminal half-life measured in weeks. That makes WFA easier to separate from other protocol phases when the goal is short, defined metabolic or autophagy pressure.
Evidence quality rating
Mechanism (cell line)
Extensive — multiple independent labs
Animal (in vivo)
Strong — breast, ovarian, lung, osteosarcoma, glioblastoma, colorectal
Human pharmacokinetics
Limited — one crossover study and one Phase I oncology trial
Human efficacy (WFA-specific)
Absent — no completed human efficacy RCT
Human safety (extract level)
Established at standard extract doses outside oncology
Formulation-specific human data
No human PK or efficacy data for purified liposomal WFA
Clinical positioning
WFA is an adjunctive compound under preclinical and early clinical investigation. The only published Phase I oncology study evaluated oral WFA in advanced high-grade osteosarcoma and established pharmacokinetic and tolerability data, not efficacy. The most advanced current human study is an ongoing ovarian cancer trial using Ashwagandha extract with liposomal doxorubicin rather than isolated WFA.
That distinction matters. The mechanistic case is strong. The clinical translation is still early.
Main limitation
All direct anticancer efficacy evidence for WFA remains preclinical. Breast and ovarian human data currently comes from whole-extract work, not purified WFA. No completed human trial has tested a bioavailability-optimised WFA formulation against a defined cancer endpoint.
In this hub
This hub covers:
Explore by cancer type
Related pages
Key references
Muniraj N. et al. — autophagy blockade, lysosomal dysfunction, and energetic collapse in breast-cancer models. https://pmc.ncbi.nlm.nih.gov/articles/PMC10893887/
Sehdev V. et al. — ER-α suppression in ER-positive breast-cancer models. https://pmc.ncbi.nlm.nih.gov/articles/PMC3129407/
Kakar S. et al. — broad oncology review of withaferin A and its translational profile. https://pmc.ncbi.nlm.nih.gov/articles/PMC9966696/
Koduru S. et al. — comprehensive mechanistic review of withaferin A anticancer activity. https://pmc.ncbi.nlm.nih.gov/articles/PMC7501947/
Kandhare A. et al. — human pharmacokinetic study showing formulation-dependent withanolide exposure. https://ui.adsabs.harvard.edu/abs/2023Heliy...922843K/abstract
Safety and pharmacokinetics of Withaferin-A in advanced stage high-grade osteosarcoma — Phase I oncology trial report. https://www.sciencedirect.com/science/article/pii/S0975947618307897
University of Louisville — recurrent ovarian cancer trial of Ashwagandha extract plus liposomal doxorubicin. https://ctv.veeva.com/study/combination-therapy-for-recurrent-ovarian-cancer
Schrezenmeier E., Dörner T. — hydroxychloroquine mechanism, tissue accumulation, and long half-life context. https://pmc.ncbi.nlm.nih.gov/articles/PMC7122276/
Hydroxychloroquine pharmacology summary — classic half-life reference. https://pubmed.ncbi.nlm.nih.gov/3179169/
Access and availability:
Source: MCS Formulas, “Withaferin A Pro Liposomal.”
50 mg WFA per capsule. Available via healthcare professional request.
https://www.mcsformulas.com/vitamins-supplements/withaferin-a-pro-liposomal/ref/14
In this section
Core pages
Cancer-type pages
Practical pages
This information is for education only. It is not medical advice, diagnosis, or treatment. Please speak with a qualified clinician before making changes to care, medication, or supplement use.
© 2026 Abbey Mitchell. All rights reserved. Please share by URL rather than copying page text.
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