08/21/2025
Is Fenbendazole currently defined by the book "Extraordinary Popular Delusions and the Madness of Crowds?" This book is an early study of crowd psychology by Scottish journalist Charles Mackay, first published in 1841. One classic example is the Dutch tulip mania. At the peak of tulip mania, in February 1637, some single tulip bulbs sold for more than 10 times the annual income of a skilled artisan. There was no actual reason for a flower to command these prices and ultimately there was a market crash and no value was given for tulip bulbs. But what about Fenbendazole?
Febendazole came to fame when the Edmond OK man Joe Tippens, who was diagnosed with small-cell lung cancer, took the veterinarian medicine Fenbendazole with daily vitamin E supplements, curcumin, and CBD oil while simultaneously taking an experimental cancer-fighting drug. Tippens says out of the 1,100 patients on that clinical trial, he was the only one who cleared of cancer1. Certainly, we are thankful and impressed by this successful case study but how much weight should be put on Fenbendazole? What does published scientific research have to say about Fenbendazole because this one success does not automatically mean a sweeping success for everyone and for all cancers.
A very major problem is that Fenbendazole has poor water solubility (0.3 µg/mL) which limits its clinical applications1,2,3,4. This is a very significant problem because of limited absorption from the gut. Even after great efforts were made toward increasing its water solubility, the results were not significant to reach the anti-cancer drug delivery requirement (5–10 mg/mL)2. This is a major hindrance to the bioavailability and actual effectiveness of Fenbendazole if it is not absorbed from the gut. A simple statement with simple truth. Elimination occurred >90% in f***s in oral dog studies5 so there was poor absorption.
Cancer cells typically die off through activity catalyzed through by p53 protein. About 50% of cancers do not have normal p53 function and most cancers have very little p53 function6,7,8,9. Stepping away from the poor bioavailability there is a problem concerning the p53 protein “the guardian of the genome”. Fenbendazole generally requires a functioning p53, a nuclear transcription factor with a pro-apoptotic function.1,10
Outside of failing the p53 activation, Fenbendazole can induce necrosis, apoptosis, and ferroptosis10. In 5-FU-resistant CRC, fenbendazole triggers apoptosis without affecting p53 expression, likely enhancing p53-independent ferroptosis-augmented apoptosis. This still will require the lack of bioavailability of water insoluble fenbendazole to be overcome.
If fenbendazole is to be used, then what would help the bioavailability? To increase the bioavailability of oral fenbendazole, it would be worthwhile to focus on dimethyl sulfoxide (DMSO), Salicylic acid, and methyl-β-cyclodextrin.1 Specifically, DMSO is a great choice as well as cyclodextrin. Without solubilizing fenbendazole, there will be limited bioavailability towards having an anticancer effect.
There is the question of taking fenbendazole with fat for absorption purposes. Science has spoken eloquently. “Fenbendazole was administered orally without food to six beagle dogs at 2.5, 5.0, 10, 20, 40 and 80 mg/kg of body weight. Increasing the dose rate did not significantly increase the amount of fenbendazole absorbed. In a separate study fenbendazole was administered to the same six beagle dogs at a dose rate of 20 mg/kg of bodyweight in food with high, medium and low fat content. The food provided 1.52, 0.70 or 0.34 g of fat per kg of body weight. Administration of fenbendazole in food with different fat contents did not affect its relative bioavailability.”11
In summary, there is a strong possibility that "Extraordinary Popular Delusions and the Madness of Crowds" is in effect with Fenbendazole. Unless the water insolubility is overcome with say, DMSO, the bioavailability of Fenbendazole does not meet the adequate concentration needed for an anticancer effect. One may hope in something but hard science has to be acknowledged first and foremost. Life does not get a “do-over”, in the words of "Indiana Jones and the Holy Grail", one must choose but choose wisely.
1 Jolie Nguyen, et al. “Oral Fenbendazole for Cancer Therapy in Humans and Animals” Anticancer Research September 2024, 44 (9) 3725-3735; DOI: 10.31838/ecb/2023.12.Si8.826
2 Ding et al. “Preparation and evaluation of fenbendazole methyl-β-cyclodextrin inclusion complexes” BMC Veterinary Research https://doi.org/10.1186/s12917-024-04056-1
3 Qiwen Duan, Yanfeng Liu and Sara Rockwell “Fenbendazole as a Potential Anticancer Drug” Anticancer Research February 2013, 33 (2) 355-362 https://ar.iiarjournals.org/content/33/2/355.full
4 Yili Ding, Zhiyuan Zhang, Charles Ding, Shufeng Xu, Zhe Xu “Preparation and evaluation of fenbendazole methyl-β-cyclodextrin inclusion complexes” https://pmc.ncbi.nlm.nih.gov/articles/PMC11103997/
5 A. McKellar, E. A. Galbraith, P. Baxter “Oral absorption and bioavailability of fenbendazole in the dog and the effect of concurrent ingestion of food” Journal of Veterinary Pharmacology and Therapeutics June 1993 https://doi.org/10.1111/j.1365-2885.1993.tb00163.x
6 Toshinori Ozaki, Akira Nakagawara “Role of p53 in Cell Death and Human Cancers” Cancers (Basel) 2011 Mar 3;3(1):994-1013 PMID: 24212651
7 Patel, Krupa R., Patel, Hitesh D. “p53: An Attractive Therapeutic Target for Cancer” Current Medicinal Chemistry, 2020-01, Vol.27 (22), p.3706-3734 PMID: 31223076
8 Andreas C. Joerger, Thorsten Stiewe & Thierry Soussi “TP53: the unluckiest of genes?” Cell Death & Differentiation vol 32, pages219–224 (2025) www.nature.com/articles/S41418-024-01391
9 Toshinori Ozaki, Akira Nakagawara “Role of p53 in Cell Death and Human Cancers” Cancers (Basel) 2011 Mar 3;3(1):994-1013 PMID: 24212651
10 Deokbae Park, Jung-Hee Lee, Sang-Pil Yoon “Anti-cancer effects of fenbendazole on 5-fluorouracil-resistant colorectal cancer cells” Korean J Physiol Pharmacol. 2022 Sep 1;26(5):377–387. PMID: 36039738
11 A. McKellar, E. A. Galbraith, P. Baxter “Oral absorption and bioavailability of fenbendazole in the dog and the effect of concurrent ingestion of food” Journal of Veterinary Pharmacology and Therapeutics June 1993 https://doi.org/10.1111/j.1365-2885.1993.tb00163.x
Dayspring Cancer Clinic is an alternative cancer treatment center that has been providing personalized care for patients for over 10 years by pinpointing the cause of and treating their individualized cancers. We take a boutique approach focusing on a handful of patients versus a mass quantity style...
