Low-Dose Naltrexone: The Best Kept Secret in Autoimmunity, Cancer, and More

What if I told you there was a single medication that could have a dramatic impact on a wide range of conditions including cancer, autoimmunity, Crohn’s disease, and long COVID (just to name a few)? And what if I told you that this medication came with virtually no side effects or adverse risks?

You’d probably either think that sounds too good to be true or be wondering why on earth this drug isn’t common knowledge. Well, it’s not too good to be true and it may just be one of the best-kept secrets in healthcare due to its application in many treatment protocols being considered “off-label”. This mighty medication I’m referring to is known as low-dose naltrexone.

Today we’re going to dive into exactly what naltrexone is, how very low doses of this drug can have some high-powered impacts on your body, the conditions this incredible protocol can help with, and what to do if you’re curious whether or not this miraculous medication can help you.

What Is Naltrexone?

Naltrexone is a type of medication known as an opioid antagonist. As an opioid antagonist, naltrexone is able to bind to the opioid receptors in your brain – blocking any other substances or chemical messengers from being able to bind to these sites. This ability to bind to your opioid receptors has made it a highly useful drug in the treatment of various addiction disorders.1

What Is Naltrexone Used for?

Naltrexone is approved by the Food and Drug Administration (FDA) to treat both opioid and alcohol use disorders. You see, naltrexone binds to opioid receptors – blocking the euphoric and sedative effects of alcohol as well as drugs like heroin, morphine, and codeine. This effect is designed to reduce and suppress cravings for these addictive substances – helping those struggling with addiction disorders find and maintain sobriety as part of a comprehensive treatment plan.1

Naltrexone has certainly been a highly useful tool in the management and treatment of addiction disorders. But this is just scratching the surface of what this mighty medication can accomplish. You see, researchers and doctors across the globe have been harnessing the power of naltrexone in “off-label” uses to aid those grappling with a wide range of conditions.

And while these uses are still considered “off-label” – meaning it hasn’t officially been approved by the FDA – there is mounting evidence that administering naltrexone at ultra-low doses can have a remarkable impact on your body.

Low-Dose Naltrexone Defined: What Exactly Does Low-Dose Naltrexone Do?

Before we dive into the conditions that low-dose naltrexone can help with, it’s important to define what “low-dose” naltrexone even means. Typical naltrexone doses used in the treatment of alcohol and opioid addiction range from 50 to 100 milligrams daily. Low-dose naltrexone, on the other hand, refers to daily doses of naltrexone that are approximately 1/10th of the typical addiction treatment dosages – usually ranging from 1 to 5 milligrams daily.2,3

These significantly lower doses of naltrexone also elicit a different response within the body through a process that goes something like this:2,3,4,5

  • Receptor site binding: When low doses of naltrexone are administered, these medication molecules make their way throughout your body where they bind to two distinct receptor sites on your cells – your opioid receptors and your toll-like receptors.
  • Upregulation of endorphins: When these medication molecules bind to your opioid receptors at these low levels, it essentially tricks your body into thinking it’s not producing enough endorphins – molecules released by your body that serve as natural pain relievers. In response, your body upregulates the natural production and release of these endorphins – leading to an increase in your baseline endorphin levels.
  • Immune cell inhibition: Meanwhile, naltrexone molecules also bind to your toll-like receptors – receptor sites found on specialized immune cells such as macrophages and microglia. When these cells are chronically overactivated, they release a cascade of proinflammatory signaling molecules that can significantly upregulate inflammation and lead to a host of negative inflammatory effects. Naltrexone binds to these sites, thus suppressing immune cell activation and dramatically reducing the production of these pro-inflammatory signaling molecules.
  • Decreased inflammation and pain: This combination of increased endorphins paired with a decrease in pro-inflammatory signaling molecules has a domino effect – positively impacting things like immune function, cell growth and proliferation, and pain response.

This potent combination of events is what allows low-dose naltrexone to exert its pain-relieving, inflammation-suppressing, and life-enhancing effects on those dealing with a wide range of life-altering conditions.

What Conditions Can Low-Dose Naltrexone Help With?

Just a handful of the conditions low-dose naltrexone has been found to have a profoundly positive impact on includes:6,7,8,9,10

  • Autoimmune diseases: By soothing and down-regulating inflammation, low-dose naltrexone can help prevent autoimmunity flare-ups as well as pump the brakes on the progression of autoimmune diseases.
  • Cancer: Low-dose naltrexone not only positively modifies cell signaling and immune function, but also binds to opioid receptors on both healthy cells and cancerous cells – helping to block the proliferation and growth of cancer cells and tumors.
  • Crohn’s disease and other inflammatory bowel conditions: Crohn’s disease and many other bowel conditions are driven by increased gut inflammation, increased intestinal permeability, and gut dysbiosis (an imbalance in the microbes that reside in your gut) – triggering pain and a laundry list of digestive woes. Low-dose naltrexone can help mitigate the underlying inflammation driving symptoms and give the gut an opportunity to begin healing and re-establishing balance.
  • Fibromyalgia and chronic pain conditions: Low-dose naltrexone can not only help relieve chronic pain but also help modulate and calm the underlying inflammation that drives pain pathways in many chronic pain conditions.

Studies have found that, in some cases, low-dose naltrexone can have life-altering impacts on patients with these conditions – drastically improving their quality of life and ability to manage chronic symptoms. What’s even more promising, is that research is finding there may be another devastating, life-hindering condition that low-dose naltrexone may be helpful in addressing.

What is this particular condition? Long COVID.

Low-Dose Naltrexone and Long COVID

Long COVID is an emerging phenomenon in which contraction of the COVID-19 virus becomes far more than just a passing sickness. Rather, those who are unfortunate enough to experience long COVID, get stuck grappling with ongoing symptoms for weeks, months, or even years after the initial viral infection has supposedly cleared.

While the specifics of the underlying factors that cause long COVID are complex and still not completely understood, we can be certain that these lingering viral-induced symptoms are attributed to a multi-faceted dysregulation of the immune response. And research is finding that low-dose naltrexone may aid in the treatment of long COVID by helping to restore balance to the immune system – with studies finding that low-dose naltrexone can:11,12

  • Boost energy levels
  • Decrease pain
  • Minimize brain fog and increase the ability to concentrate
  • Reduce chest tightness and coughing
  • Reduce immune-mediated complications such as thrombosis, digestive issues, respiratory distress, and abnormal organ tests
  • Improve overall quality of life while maximizing the ability to perform daily tasks

More time and research are needed to truly understand the role low-dose naltrexone might play in the treatment of long COVID. But so far, the results are promising – especially when combined with a comprehensive treatment plan. To dive deeper into long COVID and emerging treatment options, head over and browse through my COVID-19 articles which you can access by clicking right here.

With all these remarkable effects you’re probably curious if there’s a catch and wondering if naltrexone perhaps comes with some risky side effects.

What Are the Side Effects of Low-Dose Naltrexone?

One of the most promising and exciting aspects of low-dose naltrexone is the extremely low incidence of negative side effects. Even standard doses of naltrexone used to treat addiction disorders have been associated with minimal side effects. But with the incredibly low doses utilized in low-dose naltrexone therapy, research has found that side effects are minimal and most often include:13,14

  • Vivid dreams
  • Spontaneous, mild headaches
  • A slight increase in feelings of anxiety

What’s more, there are also zero withdrawal symptoms when low-dose naltrexone is stopped and no evidence of the development of dependence or tolerance.

Is Low-Dose Naltrexone Safe for Long-Term Use?

So far, there is no evidence to suggest that there are any dangers associated with being on low-dose naltrexone long-term. But the truth is, more time and research are needed to truly determine whether or not there is potential for safety concerns if taking low-dose naltrexone long term.

Ideally, low-dose naltrexone can be utilized as a short-term solution within a bigger, more comprehensive treatment plan that identifies and addresses the underlying factors triggering your symptoms in the first place.

Curious if Low-Dose Naltrexone Can Help You?

The more we learn about low-dose naltrexone, the more it earns its rightful reputation as an incredibly useful tool in treating a wide variety of conditions. But at the end of the day, low-dose naltrexone is exactly that – a tool. It can be incredibly useful and beneficial when used properly, but it is certainly not a “cure-all” or “quick fix”.

If you’re dealing with an ongoing condition and are curious if low-dose naltrexone can help you, it may be worth a shot. The first step is partnering with an Integrative and Functional Medicine Doctor who is well-versed in the off-label use of low-dose naltrexone. Not only will they help you determine if low-dose naltrexone is right for you and help you get started on an appropriate dose, but they’ll also help you create a customized plan to identify and address all of the underlying factors that your symptoms may be stemming from.

If you enjoyed this article and are interested in learning more about the functional medicine approach and how it can uplevel your health and well-being, I encourage you to browse through the hundreds of education-packed resources I have available on my blog, my YouTube channel,  and within my weekly email newsletter (all you have to do is enter your name and email address in the form below to subscribe).

And if you want to take it even deeper and learn how the functional medicine approach has transformed my own health and life from the inside out, you’ve got to check out my upcoming book Unexpected: Finding Resilience Through Functional Medicine, Science, and Faith. This book details my own personal journey with learning how to truly heal my body, mind, and spirit and is chock-full of practical tips to help you do the same. Click here to learn more and claim your exclusive pre-order bonuses today!


  1. Naltrexone - StatPearls - NCBI Bookshelf (nih.gov)
  2. Low-Dose Naltrexone (LDN)—Review of Therapeutic Utilization (nih.gov)
  3. The use of low-dose naltrexone (LDN) as a novel anti-inflammatory treatment for chronic pain (nih.gov)
  4. What is Low Dose Naltrexone (LDN)? | LDN Research Trust - The Low Dose Naltrexone Charity
  5. The use of low-dose naltrexone (LDN) as a novel anti-inflammatory treatment for chronic pain | SpringerLink
  6. Does LDN provide any protection against developing an autoimmune disease? | LDN Research Trust - The Low Dose Naltrexone Charity
  7. Low-dose naltrexone (LDN): A promising treatment in immune-related diseases and cancer therapy - PubMed (nih.gov)
  8. Low Doses Naltrexone: The Potential Benefit Effects for its Use in Patients with Cancer - PubMed (nih.gov)
  9. Low dose Naltrexone for induction of remission in inflammatory bowel disease patients (nih.gov)
  10. The use of low-dose naltrexone (LDN) as a novel anti-inflammatory treatment for chronic pain | SpringerLink
  11. Safety and efficacy of low dose naltrexone in a long covid cohort; an interventional pre-post study (nih.gov)
  12. Repurposing low-dose naltrexone for the prevention and treatment of immunothrombosis in COVID-19 | European Heart Journal - Cardiovascular Pharmacotherapy | Oxford Academic (oup.com)
  13. The use of low-dose naltrexone (LDN) as a novel anti-inflammatory treatment for chronic pain (nih.gov)
  14. Low-Dose Naltrexone (LDN)—Review of Therapeutic Utilization (nih.gov)

This article was originally written by Dr. Jill Carnahan, a functional medicine consultant, and author of Unexpected: Finding Resilience Through Functional Medicine, Science, and Faith.

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