Navigating the Path to Pain Relief: How to Get Low Dose Naltrexone
Immune Health

Navigating the Path to Pain Relief: How to Get Low Dose Naltrexone

Naltrexone is an anti-opioid medication with different pharmacologic properties depending on the dosage. At the higher 50 mg to 300 mg dosage, naltrexone is used to treat alcoholism and opioid use disorder, but at this dose, it has significant side effects.1

However, researchers found that at a much lower 1.5 mg to 3mg dose, low-dose naltrexone (LDN) can be used to treat pain and other conditions and diseases. These are considered off-label uses, but the lower doses work better in many cases and have far fewer side effects.2   Clinical trials are ongoing, but smaller studies suggest that low-dose naltrexone is a safe and inexpensive way to treat pain and other conditions.

What is naltrexone used for?

Researchers are testing low-dose naltrexone (LDN) to see if it has benefits for people with the following conditions: 3,4,5

  • Multiple sclerosis
  • Complex pain syndromes
  • Fibromyalgia
  • Irritable bowel syndrome
  • Inflammatory bowel disease
  • Cancer
  • Low back pain
  • Osteoarthritis
  • Weight loss
  • Autoimmune thyroid disorders
  • Psoriasis
  • Skin conditions
  • Autism
  • Stress

How does naltrexone relieve pain?

LDN works by binding to and temporarily blocking opioid mu receptors. These receptors can be found all over the body, including the nervous system, the gastrointestinal tract, and lymphocytes. LDN binds for approximately one hour and has effects that last 4 to 6 hours.6

Your brain produces more opioids when the receptor is temporarily blocked. An increase in opioids has a wide range of effects on the body. The most important thing is pain reduction. Increased opioid levels in the body last 18 to 24 hours. This means that a daily LDN dose can provide continuous pain relief.

LDN reduces inflammation by blocking toll-like receptor (TLR)-4 receptors found on immune cells (macrophages). Microglial cells in the brain that are activated produce pro-inflammatory chemicals known as cytokines. Inflammatory chemicals cause swelling, redness, and pain by increasing blood flow. The inflammatory response is designed to fight pathogens, but when activated unnecessarily, it causes you to feel ill while providing no benefits.

Many of LDN’s advantages stem from increased natural opioid release and decreased inflammation. More research in this area is required.

A woman with back pain

What are the negative effects of naltrexone?

Side effects from LDN are uncommon; they are typically mild when they occur. Reported side effects from LDN include: 

  • Difficulty sleeping
  • Nightmares
  • Unusual dreams
  • Nausea
  • Weight loss
  • Prolonged erections
  • Headaches
  • Joint pain
  • Altered mood

Starting with a low dose of naltrexone and slowly increasing it helps your body get used to it and reduces side effects. Many people find that taking low-dose naltrexone at night can minimize any side effects they experience.

The UK-based LDN Research Trust Charity spearheads low-dose naltrexone studies. Naltrexone was first FDA-approved in the United States in 1984. Low-dose or ultra-low-dose naltrexone is a safe and effective way to control chronic pain with much fewer side effects than traditional pain control options.

Low-dose naltrexone is a prescription medication that a compounding pharmacy must dispense. It is available in many forms, including tablets, capsules, orally dissolving tablets, and transdermal patches. If you have questions about low-dose naltrexone, contact one of the Invigor Medical treatment specialists.

Frequently asked questions

What is low-dose naltrexone (LDN) used for?

LDN is used to treat pain, induce weight loss, and decrease inflammation. Because LDN binds opioid receptors and immune cells, researchers believe it may treat autoimmune disorders, cancers, and pain syndromes.

Does low-dose naltrexone have side effects?

Reported side effects from using LDN are typically mild. Some people have trouble sleeping, nightmares, unusual dreams, nausea, priapism, headaches, and weight loss. Lowering the dose or taking LDN at night may reduce the side effects.

Who should not take low-dose naltrexone?

Anyone taking opioid-based pain relievers should not take low-dose naltrexone as it will block their effects and precipitate withdrawal. Naltrexone adversely interacts with some medications and supplements, so it is important to tell your doctor about all your medications, both prescription and over-the-counter, before taking low-dose naltrexone.

Why are so many people interested in low-dose naltrexone?

Low-dose naltrexone is a safe, inexpensive, and effective medication used off-label to manage pain, reduce inflammation, and treat multiple conditions and diseases including immune dysfunction, chronic pain syndromes, and cancer.

Looking to buy naltrexone online? See how Invigor Medical can help you today!


While we strive to always provide accurate, current, and safe advice in all of our articles and guides, it’s important to stress that they are no substitute for medical advice from a doctor or healthcare provider.  You should always consult a practicing professional who can diagnose your specific case.  The content we’ve included in this guide is merely meant to be informational and does not constitute medical advice.


1. Sudakin D. Naltrexone: Not Just for Opioids Anymore. J Med Toxicol. Mar 2016;12(1):71-5. doi:10.1007/s13181-015-0512-x

2. Bihari B. Bernard Bihari, MD: low-dose naltrexone for normalizing immune system function. Altern Ther Health Med. Mar-Apr 2013;19(2):56-65. 

3. Toljan K, Vrooman B. Low-Dose Naltrexone (LDN)-Review of Therapeutic Utilization. Med Sci (Basel). 2018 Sep 21;6(4):82. doi: 10.3390/medsci6040082. PMID: 30248938; PMCID: PMC6313374.

4. Low Dose Naltrexone Research Trust. What is low-dose natrexone (LDN)? Accessed November 30, 2022.

5. Low Dose Naltrexone. Accessed November 30, 2022.

6. Toljan K, Vrooman B. Low-Dose Naltrexone (LDN)-Review of Therapeutic Utilization. Med Sci (Basel). Sep 21 2018;6(4)doi:10.3390/medsci6040082

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Published: Mar 28, 2023


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