Is there any evidence that ivermectin cures cancer?

The honest answer is: no, there is no evidence that ivermectin cures cancer in humans, and the claim that it does rests on laboratory experiments that have not translated to a single cured patient.

Let me give you the mechanism first, because that is where the hope comes from. Ivermectin is an antiparasitic drug. In a petri dish, at concentrations far above what you can safely achieve in a human bloodstream, it does things to cancer cells. It can disrupt microtubules, which are the cell’s internal scaffolding. It can open ion channels and change calcium signaling. It can trigger a form of cell death called apoptosis. It can even make some cancer cells more sensitive to chemotherapy drugs. All of that is real, published, and reproducible in vitro. The problem is that a petri dish is not a person. To get those concentrations in a tumor, you would need to give a dose that would likely cause neurotoxicity, seizures, or liver damage in a living patient. The drug does not selectively accumulate in cancer tissue. It goes everywhere, and the dose needed to kill cancer cells in a dish is roughly ten to a hundred times higher than what is tolerated in a human.

Now the evidence. There is no randomized controlled trial in humans showing ivermectin shrinks tumors or extends life. There is no large observational study with hard endpoints like survival. What exists are case reports, a handful of small phase 1 and phase 2 trials in specific cancers like breast cancer and glioblastoma, and a lot of preclinical work in mice. The mouse studies are interesting, but mice are not humans, and many drugs that cure cancer in mice fail in people. The phase 2 trials that have been published are small, often single-arm, and they report things like “stable disease” or “progression-free survival at six months,” which are surrogate endpoints. They do not show cures. They do not even show a clear overall survival benefit. The one or two trials that compared ivermectin to a control group have not been replicated, and the effect sizes are modest at best.

The narrative review you mention, the one that lists eight non-oncologic drugs including ivermectin, is a review of laboratory and animal data. It is not a clinical trial. It is a summary of what has been shown in cells and in mice, and it is honest about that. The authors are not claiming these drugs cure cancer in people. They are arguing that these drugs deserve further study because they have anticancer activity in preclinical models. That is a reasonable scientific position, but it is a long way from “ivermectin cures cancer.” The gap between a drug that works in a dish and a drug that works in a patient is the graveyard of oncology. Thousands of compounds have shown anticancer activity in vitro. Almost none of them become treatments.

Here is where the money and the incentives come in. Ivermectin is off-patent and cheap. No pharmaceutical company is going to fund a large, expensive, phase 3 trial to prove it works, because they cannot make money from it. That means the evidence base will remain thin, not because the drug is secretly effective, but because there is no profit motive to test it properly. That is a real structural problem, and it applies to many repurposed drugs. But the absence of a funded trial is not evidence of efficacy. It is evidence of neglect. And neglect is not the same as proof.

The other side of the coin is the harm. Ivermectin is not a harmless sugar pill. At standard antiparasitic doses, it is generally well tolerated, but at the higher doses needed to approach anticancer concentrations, it can cause dizziness, low blood pressure, seizures, coma, and liver injury. There have been case reports of people hospitalized after self-medicating with veterinary formulations, which contain excipients not meant for human use. So the risk is real, and the benefit is unproven. That is a bad trade for a cancer patient who is desperate and willing to try anything.

My confidence here is high. I am not saying ivermectin could never have any anticancer effect in some narrow subset of patients. I am saying the evidence that exists today does not support the claim that it cures cancer in humans. The burden of proof is on the people making that claim, and they have not met it. They have shown laboratory activity, not clinical cures. If you are a patient or a caregiver, do not abandon proven treatments for this. Do not spend money on ivermectin from an online source. And if a doctor tells you it will cure your cancer, ask them for the randomized trial that shows it. They will not have one, because it does not exist.