What it is
Naltrexone is an opioid receptor antagonist. The low-dose variant typically refers to compounded preparations at a fraction of the standard dose.
How it works
At standard doses, competitively blocks mu-opioid receptors. The proposed low-dose mechanism involves transient opioid receptor blockade leading to compensatory upregulation of endogenous opioids and modulation of glial Toll-like receptor 4.
Where it's used
Standard-dose naltrexone is FDA-approved for opioid and alcohol use disorders. Low-dose use is off-label, studied in research for autoimmune and chronic pain conditions.
FDA-approved use
Standard-dose naltrexone is FDA-approved for opioid use disorder and alcohol use disorder. Low-dose use is off-label, typically via compounding pharmacies.
Tracking it
Low-Dose Naltrexone is oral, which makes consistency the whole game — a simple daily check-off with a reminder beats memory every time. with a half-life of about 4 hours, a dose log also lets a tracker model the relative amount still in your system between doses.
Source
OpenFDA
Last reviewed 2026-06-11