Low-dose naltrexone has been shown to improve symptoms of fibromyalgia and chronic fatigue syndrome with minimal side effects. However, most of the LDN studies have been small, and more research on immune system and anti-inflammatory benefits is needed.

Low-dose naltrexone (LDN) refers to daily naltrexone dosages that are roughly one-tenth or less of the standard opioid addiction treatment dosage. Most published research suggests a daily dosage of 4.5 mg, but this can vary by a few milligrams. [1]

The standard low-dose naltrexone (LDN) dosing schedule is 1.5 mg in week 1, 3 mg in week 2, and 4.5 mg in week 3 and beyond, taken once daily. This is the most-studied regimen and works well for most patients.

LDN stands for low dose naltrexone, a repurposed version of the drug naltrexone taken at a fraction of its standard dose. Naltrexone is FDA-approved for treating opioid and alcohol addiction at 50 to 100 mg per day. When the same drug is prescribed at just 0.5 to 6 mg, it appears to have an entirely different effect: reducing inflammation and modulating the immune system rather than blocking ...

This review will discuss the pharmacology and current evidence for use of Low Dose Naltrexone (LDN) for treating chronic pain. Pharmacology: Mechanism of Action

“LDN is an opioid antagonist that not only blocks the reception of opiates, but also the body’s own endogenous opioids – endorphins. However, because LDN is administered in such a 'low dose' it is believed that LDN only briefly (for 3-4 hours) obstructs the effects of endorphins.