Low-dose naltrexone (LDN) is naltrexone given at 1.5mg to 4.5mg, roughly 1/30th of the standard 50mg dose used for alcohol use disorder. LDN has a passionate community of users, mostly for chronic pain and autoimmune conditions, and a smaller community using it off-label for alcohol cravings. The honest answer on LDN for alcohol: the evidence is genuinely weak, the mechanism for alcohol effect is unclear, and most addiction specialists don’t recommend it. This article is part of our Naltrexone hub, the complete guide to using naltrexone for alcohol use disorder.
This article covers what LDN is, where the alcohol claims come from, what the actual evidence looks like, and why we don’t think it’s a reasonable first-line choice for alcohol use disorder. If you’re already considering LDN because someone has recommended it, you should leave this article able to make an informed decision rather than relying on enthusiastic word-of-mouth.
# What LDN is, exactly
LDN is naltrexone, the same molecule used at 50mg for alcohol use disorder, given at 1.5mg to 4.5mg once daily (typically at bedtime). At standard 50mg doses, naltrexone produces sustained, near-complete blockade of mu-opioid receptors. At LDN doses, the blockade is brief (a few hours overnight) and incomplete. The resulting transient blockade is hypothesised to upregulate the body’s own endorphin and enkephalin production, producing a paradoxical pain-relief or anti-inflammatory effect.
This is different mechanism territory from how 50mg naltrexone treats alcohol use disorder. Standard-dose naltrexone works by directly blocking the alcohol-reward pathway during the drinking session itself. LDN works (if it works) by upregulating endogenous opioid production over weeks to months, with no direct effect during a drinking event.
The two protocols are genuinely doing different things. The fact that they share a molecule shouldn’t be taken as evidence that they share applicability.
# Where the alcohol claims come from
The original LDN concept was developed in the 1980s by Dr Bernard Bihari for chronic conditions including HIV/AIDS and autoimmune disorders. The protocol gained a community following through the 2000s, primarily for fibromyalgia, multiple sclerosis, Crohn’s disease, and chronic pain. Most peer-reviewed LDN research is in those conditions.
Alcohol applications appeared more recently, largely as patient-reported anecdotes shared in LDN online communities, podcasts, and a handful of integrative medicine practices. The claimed mechanism: LDN reduces alcohol cravings by stabilising dysregulated endorphin systems in patients with substance use disorders.
Two small studies and several case series have looked at LDN for substance use disorders, but the evidence is not robust:
- A 2018 study of LDN for opioid use disorder (n=12) showed reduced craving signals, but with a small sample and no placebo control
- A 2020 case series of LDN for alcohol cravings reported subjective improvement in several patients, but again without rigorous controls
- No phase III trial of LDN specifically for alcohol use disorder has been completed
By contrast, standard-dose naltrexone has been validated in dozens of RCTs across thousands of patients since 1994. The asymmetry is substantial.
# What standard naltrexone has that LDN doesn’t
Three things, all important:
Mechanism of action that fits the disease. Standard naltrexone acts on the alcohol-drinking pathway directly: receptors are blocked, drinks are less rewarding, conditioning is interrupted. The intervention happens at the moment that matters. LDN, if it does anything for alcohol at all, would act over weeks via endogenous opioid upregulation, with no effect at the moment of drinking. There’s no obvious reason to expect LDN to interrupt the drinking-reward feedback loop the way standard-dose does.
Trial-validated protocols. Daily 50mg, the Sinclair Method, and Vivitrol are all backed by published, replicated, peer-reviewed RCTs. LDN for alcohol has anecdote, small case series, and a handful of underpowered studies.
Predictable dose-response. Standard naltrexone has been characterised in detail: receptor occupancy at given plasma concentrations, time to peak effect, half-life of metabolites. LDN is a pharmacological black box for alcohol, with no clear answer to “what serum concentration produces what effect on craving.”
# What LDN does have
Lower side-effect burden. At 1.5-4.5mg, the nausea, headache, and fatigue common in the first weeks of standard naltrexone are largely absent. Patients tolerate LDN much more easily than standard-dose. This is one reason why patients who tried 50mg and stopped because of side effects sometimes drift to LDN; the side effects of LDN are typically vivid dreams or mild insomnia, both manageable.
A genuinely passionate community. LDN has a network of advocates, integrative medicine practitioners, and patient communities who report meaningful improvement. We’re not saying these reports are made up; for some patients, LDN may genuinely help with cravings via mechanisms that aren’t yet well-understood. The issue is that “may help some patients via unclear mechanisms” is a lower evidence bar than what we’d want for first-line treatment of a serious condition.
The medication itself is safe at LDN doses. Naltrexone has a wide safety margin; 1.5-4.5mg is well below the threshold for any expected toxicity, and the absence of constant receptor blockade means none of the opioid-pain-medication concerns that apply to standard-dose use.
# When LDN might be reasonable
A few specific scenarios:
Patients with co-occurring chronic pain or autoimmune disease. If you’re already on LDN for fibromyalgia, multiple sclerosis, or another condition with established LDN evidence, and your alcohol use is mild and you’re seeing some craving reduction as a side effect, continuing LDN for both indications is defensible. You’re not adding a new medication; you’re noting an off-label benefit on an existing one.
Patients who have tried standard naltrexone and stopped due to side effects. If 50mg naltrexone made you intolerably nauseous and you cannot persist, LDN is a lower-stakes alternative. The evidence for LDN’s alcohol effect is weaker than for standard-dose, but if standard-dose isn’t an option for you, LDN with realistic expectations is better than no medication at all.
Patients with very mild alcohol use disorder where the goal is moderation rather than disease management. For someone drinking 8-10 drinks a week and wanting to reduce, LDN’s mild profile and low cost mean the downside of trying it is small. The expected effect size is modest, and the absence of evidence makes setting expectations important: don’t expect TSM-level outcomes from LDN.
# Where LDN doesn’t make sense
Most cases:
Moderate to severe alcohol use disorder. If you’re drinking heavily, daily, with consequences in your life, the medication question is serious enough that you should be on a treatment with strong evidence. That means standard naltrexone (or acamprosate, or disulfiram, depending on your situation; see our Naltrexone vs Acamprosate vs Disulfiram comparison). LDN is the wrong tool for this severity of problem.
As a substitute for the Sinclair Method. Some LDN advocates suggest LDN can do what TSM does without the side effects. It can’t. TSM works because the dose is at the receptor when the drink hits the reward pathway. LDN is gone from the receptor by the time you drink. The mechanism doesn’t translate.
As a “natural” or “more holistic” alternative to “real medication.” The framing of LDN as a softer or more natural option is misleading. LDN is the same molecule as standard naltrexone, just at a lower dose. Both are conventional pharmacological agents, both come from the same prescription pathway. Choosing LDN over standard naltrexone for alcohol use disorder is a choice for less evidence, not for less medicalisation.
# How to talk to a prescriber about LDN
If you want to try LDN for alcohol cravings, the most direct route is:
- A specialty LDN-experienced practitioner (some integrative or functional medicine clinics)
- An LDN compounding pharmacy in your jurisdiction (LDN is not commercially manufactured at low doses; pharmacies compound it from standard tablets)
- Be specific that you want LDN for alcohol cravings; many prescribers will require you to also have an established indication like fibromyalgia or chronic pain, since alcohol-only LDN is more off-label than off-label-LDN-for-pain
Don’t expect a standard primary-care GP or addiction specialist to prescribe LDN for alcohol use disorder. The evidence isn’t there for them to be comfortable with it. That’s not stubbornness; it’s appropriate caution.
# How AlcoLog handles LDN if you do use it
AlcoLog’s Medications card has dedicated entries for naltrexone (which can be used for both standard-dose and LDN protocols; the dose value is just different) plus six other alcohol-related preparations. Each dose gets a timestamp via the 24-hour time picker. The redose timer is set in hours + minutes, suitable for once-daily LDN bedtime dosing.
The last-24h dose list shows what you’ve taken at a glance. Pro-tier location reminders are less relevant for LDN than for TSM, since LDN is taken at a fixed time daily rather than tied to drinking events.
AlcoScore deliberately excludes medication use from its scoring. The app’s view: medication is a tool you choose to use, not a behaviour the app should grade you on. Your dose log informs you, not your score. Data stays on your device. CSV export of your last 10 sessions is free; unlimited export and PDF reports are on Pro.
