LDN for Long COVID and ME/CFS
Low-dose naltrexone, or LDN, is one of the more commonly discussed off-label treatments in the Long COVID community. It is inexpensive, usually well tolerated, and has several plausible biological mechanisms. The catch is that the evidence is limited, and it doesn't work for everyone. Here is a clear look at what LDN is, how people access it, and what we actually know so far. You can read reviews of people who have used LDN here.
A Brief History
Naltrexone is not a new drug. It was first approved in the US in 1984, and standard oral tablets are typically 50 mg. At that dose, naltrexone is used mostly for alcoholism and opioid addiction.
In the mid-1980s, New York physician Bernard Bihari began exploring much smaller doses, initially in people with HIV/AIDS and later in conditions such as multiple sclerosis and other immune-related illnesses. That off-label use became known as low-dose naltrexone. Long before Long COVID existed, LDN was being used by some clinicians for fibromyalgia, MS, Crohn’s disease, chronic pain, and related conditions.
What It Is and How It Might Work
LDN is naltrexone given at a much lower dose, often around 0.5 to 4.5 mg per day (one-tenth a standard dose or less). Some Long COVID studies have used doses up to 6 mg.
At low doses, naltrexone may act differently than it does at standard doses. The main theories are that it briefly blocks opioid receptors, which may alter the body’s own endorphin signaling, and that it may reduce neuroinflammation through effects on immune signaling and microglia.
A 2025 laboratory study added another possible mechanism: natural killer cells from Long COVID patients taking LDN showed restored function of a calcium ion channel called TRPM3. That is interesting biology, but it is not the same as proving clinical benefit. Mechanistic findings can support a hypothesis; randomized trials are still needed to show whether patients actually improve because of the drug.
How People Access It
LDN is not FDA-approved for Long COVID, and in the United States there is no standard FDA-approved low-dose naltrexone tablet. Commercial oral naltrexone is generally sold as a 50 mg tablet, so LDN is usually prescribed through a compounding pharmacy, which prepares capsules or liquid at the requested dose. If you'd like to find a compound pharmacy near you, click here.
Historically, LDN was prescribed mostly by integrative or functional-medicine clinicians, along with some pain specialists, rheumatologists, neurologists, and ME/CFS-oriented clinicians. As interest in Long COVID has grown, some Long COVID clinics and primary care doctors have also become more familiar with it. Many clinicians remain cautious because it is off-label and compounded.
Clinicians who use LDN for post-viral illness often follow a “start low, go slow” approach, sometimes beginning below 1 mg and gradually increasing, because many patients with Long COVID are sensitive to new medications.
Reported Benefits
In patient reports and small observational studies, LDN has been associated with improvements in fatigue, brain fog, sleep, pain, post-exertional malaise, and daily functioning. When it helps, the effect often appears gradually over weeks or months.
But the key words are “associated with.” LDN is not a cure, does not help everyone, and reported improvements are usually partial rather than dramatic.
Side Effects and Safety
LDN is generally described as well-tolerated. Commonly reported side effects include vivid dreams, insomnia or disrupted sleep, headache, light-headedness, and mild gastrointestinal symptoms. These are often temporary, and some people adjust the timing or dose with their clinician.
The most important safety issue is opioids. Naltrexone blocks opioid receptors and can interfere with opioid pain medication. It can also precipitate withdrawal in people who are opioid-dependent. Anyone taking opioids, tramadol, buprenorphine, methadone, or planning surgery or a procedure should discuss this carefully with a clinician. People with significant liver disease also need medical guidance.
This is background information, not medical advice. LDN is something to discuss with a qualified prescriber who knows your medications and medical history.
What the Research Actually Says
A 2025 systematic review that searched the literature through May 1, 2025 found no completed randomized controlled trials of LDN for Long COVID. It identified four small observational before-and-after studies, with about 155 patients total. Those studies suggested possible improvements in fatigue, cognition, sleep, pain, and functioning, but the certainty of the evidence was low.
A separate 2025 systematic review and meta-analysis also found preliminary signals, especially for fatigue, brain fog, headaches, and sleep disturbance, but emphasized that stronger randomized trials are needed.
The limitations matter. These were not placebo-controlled trials. Participants were often people actively seeking treatment, and some studies included other therapies or did not fully control for coexisting treatments. That makes it hard to separate the effect of LDN from expectation, natural recovery, regression to the mean, or other care.
The trial landscape is moving. The British Columbia placebo-controlled trial of LDN for post-COVID fatigue enrolled 160 participants and is now listed as completed, but results haven't been released. Until randomized results are available, the most honest summary is this: LDN is a plausible, relatively accessible, generally well-tolerated option with promising early signals, but it is not yet proven for Long COVID.
That makes it reasonable to discuss with a knowledgeable doctor, and also a reason to watch the trial results closely rather than treating the question as settled. If you have tried LDN, please leave a review here. If you'd like to find a provider who offers LDN, or a compound pharmacy that can make it, search our database here.