Low-dose naltrexone (LDN): what it is and what the research shows
The same medicine used for addiction treatment behaves differently at a tenth of the dose. The early research is promising and still small.
At a glance
Naltrexone is an FDA-approved medicine that helps people who have stopped drinking alcohol or using opioids.1 Low-dose naltrexone (LDN), generally 1 to 5 mg a day, is an off-label use studied mainly for chronic pain and inflammatory conditions such as fibromyalgia.2 Small trials are encouraging but limited. LDN is usually compounded by licensed U.S. pharmacies because the low doses are not commercially made. It blocks opioid medicines, so it is not for anyone who takes opioids.
In this guide7 sections
Same drug, very different dose
At its standard dose, naltrexone blocks opioid receptors and is used with counseling and support to reduce cravings in people who have stopped drinking or using opioids. Low-dose naltrexone uses the same molecule at roughly a tenth of that amount or less, commonly 1 to 5 mg a day.2
Because those strengths are not sold as standard tablets, LDN is usually compounded for each patient by a licensed U.S. pharmacy. Compounded medicines are not FDA-approved, and using naltrexone at low doses for pain or inflammation is off-label.
How low doses are thought to work
Researchers propose two main effects. A brief, partial block of opioid receptors may prompt the body to increase its own opioid signaling afterward, and naltrexone may calm immune cells in the nervous system called glia by acting on a receptor known as TLR4, reducing inflammatory signaling.23
These mechanisms come mostly from laboratory and early clinical work. Reviews describe the low-dose uses of naltrexone as recently and still scarcely scientifically evaluated.2
What the research shows
The best-known trial enrolled 31 women with fibromyalgia in a randomized, double-blind, placebo-controlled crossover design. Baseline pain fell 28.8% on LDN versus 18.0% on placebo, and LDN was rated as tolerable as placebo. The authors called for larger parallel-group trials.4
Smaller studies and case reports suggest possible benefits in Crohn’s disease, multiple sclerosis, and complex regional pain syndrome. A 2014 review still called LDN for chronic disorders highly experimental, noting small trials and few replications.3 It should not replace established treatment for any of these conditions.
- Promising: small trials in fibromyalgia and other chronic pain
- Early: reports in inflammatory and autoimmune conditions
- Not established: benefits for healthy aging or general wellness
- Needed: larger, longer randomized trials
Side effects and who should not take it
LDN is generally well tolerated in studies. Vivid dreams, trouble sleeping, and headache are among the effects most often mentioned, and they often ease over the first weeks or with a change in dose timing.
Naltrexone blocks opioid medicines, including some cough, diarrhea, and pain medicines, methadone, and buprenorphine.1 Taking it with or soon after opioids can cause withdrawal or leave pain uncontrolled. Tell your clinician about every medicine you take, and about liver or kidney disease, depression, pregnancy, or breastfeeding.
LDN at Everdawn
Low-dose naltrexone is part of Everdawn’s longevity range. A licensed clinician reviews your history, current medicines, and goals and decides whether LDN is appropriate; if it is, a licensed U.S. pharmacy prepares it. Learn more about Everdawn longevity care and the longevity and peptides program, or read about whole-person telehealth.
Common questions
Is low-dose naltrexone FDA-approved?
Naltrexone is FDA-approved for alcohol and opioid use disorders. Low-dose use for pain or inflammation is off-label, and compounded LDN is not FDA-approved.
Can I take LDN with opioid pain medicine?
No. Naltrexone blocks opioids and can cause withdrawal or block pain relief. Tell your clinician about any opioid use, including cough or diarrhea medicines, before starting.
Why is LDN compounded?
The usual low doses, often 1 to 5 mg, are not made as standard commercial tablets, so a licensed pharmacy prepares them for each patient.
Does LDN help autoimmune disease?
Early studies and case reports are interesting, but the evidence is limited. LDN should not replace established treatment, and any use should be coordinated with the clinician managing the condition.
References
- Source 1: MedlinePlus (NIH): Naltrexone (opens in a new tab)
- Source 2: Toljan K, Vrooman B. Low-dose naltrexone (LDN): review of therapeutic utilization. Med Sci (Basel), 2018 (opens in a new tab)
- Source 3: Younger J et al. The use of low-dose naltrexone (LDN) as a novel anti-inflammatory treatment for chronic pain. Clin Rheumatol, 2014 (opens in a new tab)
- Source 4: Younger J et al. Low-dose naltrexone for the treatment of fibromyalgia: a randomized, double-blind, placebo-controlled crossover trial. Arthritis Rheum, 2013 (opens in a new tab)
- Source 5: FDA: Compounding and the FDA, questions and answers (opens in a new tab)
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This guide provides general educational information and is not medical advice, diagnosis, or treatment. Treatment decisions require an appropriately licensed clinician who understands your history and circumstances.
Images are illustrations, not Everdawn members or clinicians.