Ivermectin primer - Data on efficacy, its risks, possible drug interactions, and how to get access

Ivermectin is a horse dewormer! :horse: It’s also a Nobel-prize winning drug used widely in humans to treat parasites. Here’s what you should know:

  • It’s one of the top drugs for treating long haul.
  • It also doesn’t work for most people. That’s why it’s hard to see why it’s one of the better/best drugs that we know of right now. The ‘best’ drugs usually don’t work.
  • Some long haulers report very negative reactions to this drug, like other top treatments. They’re all double-edged swords that cut the wrong way for some people.


The following video goes over survey data on what’s helping people recover. Scroll down for a quick summary.

Whereas HBOT is the most proven treatment, survey data suggests that 5 other treatments are comparable to HBOT in terms of efficacy. 4 of them including ivermectin are shown below:

Unfortunately, the response rate is low. Only 4.3% of surveyees reported that they are currently mostly recovered AND rated the drug highly. If partial recoveries are included (and/or you believe that you may need multiple successful treatments to become mostly/fully recovered), then the response rate would be higher.

Here’s another way of looking at the data… less than half reported significant improvement on ivermectin:

There’s also something weird going on with the Long COVID surveyees. I think ivermectin was quite popular in the past due to viral persistence theories. However, it’s politically in a weird space as most LC groups are quite anti-ivermectin for political reason. I don’t know if the survey data is reflecting that. Normally you might expect ivermectin to be more effective in LC than post vac because LC patients may have persistent SARS-CoV-2 in them.


Flip flops on ivermectin

The Bruce Patterson / Ram Yogendra / Eric Osgoode group were initially keen on ivermectin and recommended its use. Then Patterson and Osgoode started pooh-poohing ivermectin around the time that the FDA tweeted: “You are not a horse. You are not a cow. Seriously, y’all. Stop it.” A Mother Jones article contains a tidbit on the Patterson’s group position at the time:

Patterson offers a treatment protocol that he describes as being specifically tailored to a patient’s test results—often a combination of off-label medications including blood pressure medications, steroids, an HIV medication called maraviroc, and the controversial antiparasitic drug ivermectin
Dr. Ram “Yo” Yogendra, tells me the team is now moving away from ivermectin because low-dose steroids work just as well

So the lesson here is to not place too much weight on what doctors say about a drug. They’re just… not that reliable when it comes to treatment outcomes. They’re just not making a detailed effort to track how well their patients are doing. Here’s another flip flop on ivermectin:

Gustavo Aguirre Chang was initially a huge proponent of ivermectin.

  • His July 2020 (Chang et al.) paper claimed 94% of patients had clinical improvement to some degree.
  • In his October 2021 paper (Chang and Figueredo), he rolled back that claim a little: “the majority responded quickly to treatment against Viral Load with IVM. Currently, the response is less, requiring higher doses and more days of treatment.”
  • In 2023, his focus has shifted to microclots and his Microclots Indication Test (an online questionnaire-based test). See this Youtube video.


Proponents of ivermectin claim that it is extremely safe. Sometimes they will say that billions of dollars have been administered in Africa and that VIGIAccess has very few adverse event reports about ivermectin. The problem there is that VIGIAccess receives very little safety data from Africa - that’s why almost all of its reports come from First World countries.


More importantly, ivermectin is less safe in chronic illness patients than in health patients. Recall the graph from before - it shows that a few people report ‘significant worsening’ from ivermectin.

So, be careful! While it may be safer than most other drugs being used to treat long haul, you can have a bad reaction to it. You can start with low dosages and you can discontinue early if your symptoms are going the wrong way.

Does ivermectin cross the blood-brain barrier? + P-glycoprotein (P-gp/MDR1/ABCB1) gene mutations

Most of the scientific literature is of the opinion that ivermectin crosses the blood-brain barrier and that the P-gp transporter pumps it back out. Effectively it is not very good at crossing the blood-brain barrier (where it may cause neurological side effects).

However, P-gp does not work as well if:

  1. The patient has mutations in the gene that cause it not to pump/efflux ivermectin well.
  2. The patient is taking drugs that cause P-gp not to function as well such as ivermectin, colchicine, Paxlovid, and other drugs. Regarding ivermectin’s effect on p-gp, there was a study where patients were accidentally given 10X the normal dose of ivermectin. Their side effects weren’t that bad.
  3. Other drugs can affect CYP3A4 enzymes that break down ivermectin, causing it to break down more slowly and to accumulate in the body.

Rebecca Chandler theorizes that P-gp/MDR-1 gene mutations make some people vulnerable to neurological side effects. A pharmacogenetics test and genetic counselor could spot any such gene mutations and potentially anticipate potential problems with ivermectin.

In practice… you could simply start with low doses and work your way up. So then you would be more resilient against possible drug interactions.

More info

Deep dive into Metabolism and interactions of Ivermectin with human cytochrome P450 enzymes and drug transporters, possible adverse and toxic effects: Metabolism and interactions of Ivermectin with human cytochrome P450 enzymes and drug transporters, possible adverse and toxic effects | Archives of Toxicology

Higher dosages???

There have been many trials of ivermectin on Long COVID. Some of the studies tried a standard dose of 0.2mg/kg for 5 days. Other studies tried 3 times that dose: 0.6mg/kg for five days.

I do not have a lot of information as to whether higher doses can have higher efficacy. Survey data suggests that higher doses are more effective (and risky) for fasting, black seed oil, and HBOT.

Daily dosing???

Some people find that they need to stay on the drug and to take it every day to keep symptoms down. (You can easily figure out if this is the case via trial and error.)

Perhaps watch out for drug interactions because if you suddenly start taking a CYP3A4 inhibitor in the future, ivermectin can build up in your body to much higher dosages. However, mild overdoses don’t seem to have very serious side effects.

Accessing this drug - it’s not that hard

In many countries, there are freedom movement doctors or alternative doctors who will prescribe it through telehealth.

I’ve compiled country-specific information here: Ivermectin - Long Haul Wiki

If your state/province territory has no telemed options available, you can try to get it through an Indian doctor. They can prescribe the drug and ship you your prescribed drugs; you may have to do paperwork for your country’s customs process. *You have to take a risk as to whether or not it will get past customs. Facebook support groups have some information on this route.

Sketchier non-telemed options

The same Long Haul Wiki page has information on other routes:

  • Going to a jurisdiction like Mexico where it’s sold over-the-counter.
  • Buying it online.
  • Veterinary ivermectin. This route is usually not very convenient… it usually makes more sense to buy human ivermectin online.

You assume the risks of taking these non-traditional routes. Please do your research, know what you’re doing, and please don’t do stupid stuff like overdosing yourself by eating an entire tube of ivermectin. (When you weigh 1/10th of what a horse weighs, you should use a lower dose.)


It’s unfortunately that ivermectin has become politicized, leading to some people to overstate the drug’s dangers while others overstate its safety. It’s one of the safer long haul treatments but it is not risk-free and a few people report reacting badly to it.

It is one of the top treatments right now and it’s unfortunate that people aren’t figuring this out.

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