Low-Dose Naltrexone
weak data
The Dose Guy’s verdictOct 27, 20264 sources
Worth a careful try if you live with fibromyalgia-type pain or Crohn’s and the usual options have not done enough, though in Crohn’s the newest trial saw fatigue improve while remission did not. Naltrexone has decades of safety behind it, and at this dose the most common price is vivid dreams. The honest catch: the small early trials looked encouraging and the bigger recent ones came back flat, so go in expecting a maybe, not a fix. One rule with no exceptions: LDN blocks opioid painkillers, so never combine them.
What it is
Naltrexone is an opioid blocker, approved at 50 mg a day for alcohol and opioid dependence, where it sits on the receptors around the clock. LDN is the same drug at roughly a tenth of that, taken at bedtime. At this dose it blocks the receptors for only a few hours, and the theory is that your body answers by turning up its own endorphin signaling for the rest of the day. The second theory is the one that excites the pain crowd: low-dose naltrexone also quiets microglia, the immune cells that live in your brain and spinal cord, which are thought to keep pain amplified in conditions like fibromyalgia.
Neither mechanism is proven in people, and LDN is not a longevity drug despite turning up in the same clinics. Like rapamycin, it is a real, approved drug being run off-label, and the question is whether the off-label use holds up. For fibromyalgia, the approved options like pregabalin and duloxetine have firmer trial support. LDN’s case is that it is gentler, and worth a try when those either failed or flattened you.
What the research shows
A familiar pattern: small trials looked good, and the bigger, newer ones mostly came back flat.
Realistic protocols
Start low at bedtime and only climb while it is still helping. The common start is 1.5 mg at night, or 0.5 to 1 mg if you know you are sensitive to medications. If sleep holds, step up by about 1.5 mg every week or two. Most people settle between 3 and 4.5 mg, and 4.5 mg is the dose most of the trials ran. If a lower dose is already doing the job, stay there; nobody wins a prize for reaching 4.5. Give whatever dose you land on two to three months before calling it a miss, because FINAL ran 12 weeks and the effect, when it comes, comes slowly.
It needs a prescription, and at this dose it is usually filled by a compounding pharmacy as capsules or a liquid. Ask for immediate release; slow-release versions defeat the point of a short blockade. If the dreams or broken sleep do not settle after a couple of weeks, move the dose to the morning. Plenty of people do fine that way.
The opioid rule shapes your whole life on LDN. No tramadol, codeine, oxycodone, or any other opioid painkiller while you are on it. Stop LDN a few days before any planned surgery and tell the surgical team you take it, so pain control is not a surprise on the day.
Side effects
In the trials, LDN’s side effects barely separated from placebo. The ones that show up:
