Fenbendazole for Cancer: What You Need to Know
Fenbendazole is a medicine used to treat worms in animals. Some people think it might help fight cancer too. But doctors and scientists say it’s not safe for people to use, and it hasn’t been proven to work against cancer in humans.
One person’s story made fenbendazole famous, but he was also getting proven cancer treatment at the same time. Lab studies show it might fight cancer, but no human studies have been done. Some people who tried it got very sick with liver problems.
What is Fenbendazole?
Fenbendazole is a drug that kills worms in pets and farm animals. It was made in the 1970s and works by breaking down tiny parts inside worm cells, which kills the worms.
The drug is only approved for animals – never for people. You can buy it as powder, paste, or pills, but only for treating animals. The FDA (the group that approves medicines for people) has never said it’s okay for humans to use.
When people take fenbendazole by mouth, very little gets into their blood. This means it might not work well as a cancer treatment, even if it kills cancer cells in lab dishes.
The Joe Tippens Story
Most people heard about fenbendazole from Joe Tippens, a man from Oklahoma. In 2016, doctors told him he had lung cancer that had spread all over his body. They said he only had three months to live.
Joe was getting a new cancer treatment called Keytruda in a medical study. While doing this, a friend who was a vet told him about fenbendazole. The friend said someone used it to cure their brain cancer, though this story was never proven.
Joe started taking 222 mg of fenbendazole three days a week while still getting the Keytruda treatment. After three months, his scans showed no cancer. He’s been cancer-free for over eight years.
Joe shared his story online, and millions of people read it. But here’s the important part: Joe was getting Keytruda, which is a proven cancer drug that can cure some people. Doctors think the Keytruda probably cured Joe, not the fenbendazole.
What Lab Studies Show
Scientists have done many tests with fenbendazole and cancer cells in labs. These studies show that fenbendazole can kill cancer cells in several ways:
It Stops Cancer Cells from Dividing
Cancer cells need to divide to grow and spread. Fenbendazole breaks down tiny tubes inside cells that help them divide. When these tubes break, cancer cells can’t make copies of themselves and they die.
Lab studies show fenbendazole works better on cancer cells than normal cells. This means it might be safer than some cancer drugs that hurt healthy cells too.
It Cuts Off Cancer’s Food Supply
Cancer cells need lots of sugar to grow. Fenbendazole stops cancer cells from eating sugar by blocking the proteins that bring sugar into the cells. Without enough food, cancer cells get weak and die.
It Turns On the Body’s Cancer Defense
Our bodies have a protein called p53 that’s supposed to kill cancer cells. Fenbendazole makes p53 work better, which helps the body fight cancer naturally.
It Attacks Cancer in Multiple Ways
Unlike some cancer drugs that only work one way, fenbendazole attacks cancer cells through many different paths. This might make it harder for cancer to become resistant to treatment.
Why It Doesn’t Work Well in Real Life
Even though lab studies look good, there are big problems with using fenbendazole as a cancer treatment:
The Body Can’t Absorb It Well
When people swallow fenbendazole pills, most of it doesn’t get into their blood. Lab studies work because scientists put the drug directly on cancer cells. But when you take a pill, very little reaches the cancer.
Animal Studies Show Mixed Results
Some studies in mice show fenbendazole helps fight cancer. But other studies found that cancer actually grew faster in mice given fenbendazole. This makes scientists worried about how it might affect people.
No Human Studies Have Been Done
Scientists have never tested fenbendazole safely in people with cancer. All the good results come from lab dishes and animals, which often don’t work the same way in humans.
Serious Safety Problems
People who tried fenbendazole have had dangerous side effects:
Liver Damage
Several people got severe liver damage after taking fenbendazole. One 80-year-old woman’s liver almost failed after taking it for just one month. Her skin turned yellow, and blood tests showed her liver was badly hurt.
The liver damage went away after she stopped taking fenbendazole, but her cancer didn’t get better either.
Blood Problems
The FDA warned that fenbendazole can destroy bone marrow, which makes all your blood cells. When this happens, people can’t fight infections, their blood won’t clot, and they become very weak.
This problem has happened in dogs taking fenbendazole, and doctors worry it could happen to people too.
Drug Interactions
Fenbendazole can make other medicines more dangerous. It makes Tylenol much more poisonous to the liver. People taking other medications could have serious problems.
What Doctors Say
All major medical groups say people should not use fenbendazole for cancer. Here’s why:
- The FDA says “NOT FOR USE IN HUMANS” on all fenbendazole products
- No cancer organizations recommend it
- Doctors have seen patients get hurt from using it
- It hasn’t been proven to work in people
Doctors worry that people might skip proven cancer treatments to try fenbendazole instead. This could let cancer get worse while people try something that doesn’t work.
Legal Issues
It’s not illegal to buy fenbendazole, but doctors can’t prescribe it for people. The drug is only made for animals, so it doesn’t meet the safety standards for human medicines.
Companies can’t legally sell fenbendazole as a cancer treatment. Anyone who does this could get in trouble with the law.
Important Warnings
This information is just for learning – it’s not medical advice. If you’re thinking about using fenbendazole:
- Remember it’s not approved for people
- It can cause serious liver and blood problems
- It probably won’t work as a cancer treatment
- You could delay getting real treatment that works
Never use fenbendazole instead of proven cancer treatments without talking to your doctor first.
If You’re Still Considering It
If you decide to try fenbendazole despite the risks:
- Tell your doctor so they can watch for problems
- Get blood tests to check your liver and blood cells
- Stop taking it immediately if you feel sick
- Don’t take it with Tylenol or other liver-damaging drugs
The Bottom Line
Fenbendazole might help fight cancer someday, but right now it’s not safe or proven for people to use. The one famous success story probably worked because of real cancer treatment, not fenbendazole.
Scientists need to do proper human studies before anyone can say fenbendazole works for cancer. Until then, people should stick with proven treatments that doctors know are safe and effective.
Cancer is too serious to treat with unproven medicines. Always work with your doctor to find the best treatment for your specific situation.
A Possible Alternative?
Mebendazole, a drug that is approved for use in humans, offers us one possible alternative to Fenbendazole.
While it’s not FDA approved as a cancer treatment, new studies show it may offer benefit in the treatment of cancer.
And unlike Fenbendazole, a doctor can legally prescribe it for people.
Primary Research Studies
Duan, Q., Liu, Y., Rockwell, S. (2013). Fenbendazole as a potential anticancer drug. Anticancer Research, 33(2), 355-362. PMC3580766
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Key study establishing fenbendazole’s anticancer mechanisms
Dogra, N., Kumar, A., Mukhopadhyay, T. (2018). Fenbendazole acts as a moderate microtubule destabilizing agent and causes cancer cell death by modulating multiple cellular pathways. Scientific Reports, 8, 11296.
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Comprehensive Nature study on fenbendazole’s mechanisms of action
Choi, M.K., et al. (2023). Anti-cancer effect of fenbendazole-incorporated PLGA nanoparticles in ovarian cancer. Journal of Gynecologic Oncology, 34(4), e58. PMC10482585
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Research on improved drug delivery systems
Park, D.H., et al. (2022). Anti-cancer effects of fenbendazole on 5-fluorouracil-resistant colorectal cancer cells. Biochemical and Biophysical Research Communications, 617, 104-110. PMC9437363
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Study on drug-resistant cancer cells
Clinical Case Reports
Hosoya, K., et al. (2021). Drug-induced liver injury in a patient with nonsmall cell lung cancer after the self-administration of fenbendazole based on social media information. Case Reports in Oncology, 14(2), 886-892. Karger Publishers
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Documented case of liver toxicity
Multiple case reports from various medical journals documenting adverse effects in humans using fenbendazole off-label
Regulatory and Safety Information
U.S. Food and Drug Administration (2023). Dear Veterinarian Letter regarding adverse events associated with extra-label use of fenbendazole in dogs. FDA Animal & Veterinary Division
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Official FDA safety warnings
