In recent weeks, posts claiming that fenben for humans — an ingredient in dog deworming medication — cures cancer have gained traction on social media. The claims are based on the anecdotal story of Joe Tippens, who claimed that his lung cancer went into remission after taking fenbendazole for human consumption. Health Feedback has investigated the claim and found that it’s likely not true.
Despite the claims being widely shared and promoted, fenbendazole has never been approved for use as a cancer treatment in people. It has been extensively studied as a veterinary medicine and is known to be safe for dogs, but it hasn’t been studied in humans for extended periods of time or with varying doses. In fact, it is illegal to advertise or sell fenbendazole for human use in the United States, as it has not been properly tested for safety.
Scientific studies have shown that fenbendazole may suppress the growth of cancer cells in vitro and in vivo, but not as a stand-alone treatment for humans. The drug is thought to work by targeting microtubules (MT) in cancer cells, preventing their proper formation and triggering cell death. However, MT depolymerization isn’t unique to fenbendazole and is already the target of several other approved cancer treatments.
One study, for example, showed that fenbendazole has a similar effect to the vinca alkaloids berberine and sodium dichloroacetate when treating mice with EMT6 tumors. This is because fenbendazole interacts with a specific location on tubulin, similar to the action of these other vinca alkaloids. The authors of this study also reported that fenbendazole caused apoptosis in the cancer cells through upregulation of p21 and downregulation of cyclins B and D during the G1/S phase, but not in quiescent cells.
Another scientific paper published in 2022 showed that fenbendazole could reactivate the gene p53, which inhibits tumor development. This is similar to the way other cancer drugs work, such as doxorubicin and methotrexate.
Despite the lack of clinical trials, a growing number of individuals have decided to take fenbendazole for themselves. This is largely because the medicine is cheap and readily available without prescription in many countries. Health Feedback has spoken to a specialist cancer information nurse at Cancer Research UK, who told us there’s “insufficient evidence that fenbendazole can cure cancer. It hasn’t been through any clinical trials to find out if it is a safe or effective treatment.” It should be noted that these nurses also told us that the claim that cancer is caused by parasites is false, which we have previously covered here.