Low Dose Naltrexone (LDN) Fibromyalgia and Chronic Fatigue Syndrome Resource Center


Low Dose Naltrexone (LDN) …

Low dose naltrexone is cheap, readily available and safe...but does it work in FM and ME/CFS?

Low dose naltrexone is cheap, readily available and safe…but does it work in FM and ME/CFS?

Could a low cost, easily available drug that most doctors don’t know about help with your pain or other symptoms. It just might.


Low dose naltrexone (LDN) seems, at first glance, like a strange drug for people with chronic fatigue syndrome (ME/CFS) or fibromyalgia.  Usually used in high doses to combat alcoholism and narcotics withdrawal, Naltrexone blocks the opioid/endorphin receptors in the brain. LDN has the advantage of being cheap, easily produced in compounding pharmacies and safe.

But why would a drug that’s used to get people off of narcotics benefit people with fibromyalgia, ME/CFS and other disorders?

Feeling Good (Finally)

There are couple of reasons… For one low dose naltrexone appears to increase the levels of “feel good” agents called endorphins. Some studies suggest that natural pain relievers like endorphins and other substances may be low in pain disorders like fibromygalgia and chronic fatigue syndrome (ME/CFS).

Are All the “Feel-Good” Pathways Blocked in Fibromyalgia and Chronic Fatigue Syndrome?

By blocking the receptors for endorphins, LDN appears to trick the brain into producing more of them. The 4-6 hours or so the drug remains in one’s system appears to be sufficient to boost the levels of endogenous opioids (those naturally found in the brain) for 18-24 hours. Given that endorphins are known as ‘natural pain relievers’ having more endorphins  floating around might be a very good thing for people with FM and similar disorders.

A recent case study suggested the endorphin scenario might be a viable one. A 37-year-old professor with sharp pains, burning sensations, dull pain, dry, painful eyes, sleep issue, difficulties with concentration and agitation received substantial relief from LDN. .

The Immune –  Autoimmune Connection

LDN also appears to be able to regulate the activity of immune cells in the central nervous system called microglial cells. When these cells get turned on they produce pro-inflammatory cytokines, reactive oxygen species (free radicals) and nitric oxide – all of which are under study in ME/CFS and/or FM.

Microglial cells, in fact, may be a key component of the ‘sickness response’ that produces the fatigue, fluey feelings, pain, etc. when we come down with an infection. Some researchers believe these cells may be chronically turned on in ME/CFS and FM. LDN’s ability to block a key receptor (TLR 4) on microglial cells appears to inhibit them from becoming activated.


Many women with chronic fatigue syndrome (ME/CFS) reportedly experience remissions during pregnancy when high levels of endogenous opioids are present. They then often experience relapses several months after pregnancy when the levels of those opioids fall. This pattern suggests that one or more of the opioid receptors that LDN effects could play a role in these disorders.

LDN Might Be Effective in Chronic Fatigue Syndrome and/or Fibromyalgia Because…

LDN may be able to reregulate immune functioning and increase neurotransmitters called endorphins that may be low in the disorder. LDN’s ability to modulate natural killer cell activity upwards and reduce B-cell activity could help to re-regulate the immune response in ME/CFS and/or FM. It’s ability to reduce microglial functioning could reduce the fatigue, pain and other symptoms.

Fibromyalgia LDN Studies

Two small Stanford fibromyalgia studies suggested low dose naltrexone can significantly help with fibromyalgia/  A 2009 single-blind crossover study found LDN significantly reduced pain, fatigue and stress levels. Once patients were off the drug, their symptom levels quickly returned to normal.  Intriguingly, a measure of inflammation called erythrocyte sedimentation level (ESR) predicted 80% of the responses. The fact that higher ESR’s were associated with greater reductions in symptom severity suggests that inflammation could play a large role for some with FM.

A larger placebo-controlled, double-blinded, crossover study had (dose 4.5 mg/day) similar results: reduced pain, improved mood, and general satisfaction with life. Fatigue and sleep, however, were not significantly affected.

Jarred Younger has lead the way in demonstrating LDN’s effectiveness in FM. His lab at the University of Alabama at Birmingham (the Neuroinflammation, Fatigue and Pain Lab) has a variety of LDN studies planned:

  • Determining proper dosage. A dose-ranging study will determine if lower or higher dosages work better for some people.
  • Determining if LDN helps in other conditions such as rheumatoid arthritis, osteoarthritis, CFS, and perhaps depression.
  • A chronic fatigue syndrome study
  • A large (200+ person) clinical trial of LDN and fibromyalgia

Read more: Low Dose Naltrexone, Inflammation, and Pain: A Different Approach to Fibromyalgia

Chronic Fatigue Syndrome/Fibromyalgia Doctors Report

LDN is Dr. Nancy Klimas’ first-line treatment for the pain associated with fibromyalgia and chronic fatigue syndrome.  She has found the drug to be effective and safe. Dr. Ginerva finds the drug works in about 60% of her FM patients. (See link to blog below.)

Getting Low Dose Naltrexone

The preliminary evidence continues to show that low-dose naltrexone has a specific and clinically beneficial impact on fibromyalgia pain. The medication is widely available, inexpensive, safe, and well-tolerated. (Younger et. al.)

  • Find doctors that prescribe LDN here and here.
  • Find pharmacies that compound LDN here and here.  LDN Science asserts many compounding pharmacies are not reliable. They provide a list of 7 pharmacies they consider reliable here.  They recommend that LDN not be used in its ‘slow-release’ form and that calcium carbonate not be used. Avicel, lactose and sucrose fillers work fine.
  • Immune Therapeutics – the drug manufacturer licensed to market LDN drugs – partnered with KRS Biotechnologies in Jan. 2015 produce a standardized version of LDN for sale to the public and clinical trials. Costs for this high-quality source of LDN are $1 a tablet. Find more about this here.

The LDN website states that LDN is sold by Mallinckrodt as Depade, and by Barr Laboratories as naltrexone, and that a one month supply ranges from $15 to $40.


LDN Science reports that in Spring 2017 a month’s supply (30 capsules) was about 36 dollars plus a shipping fee.


Dr. Neil Beck reported:

“People vary so much in their condition, body mass, absorption, sensitivity to and excretion of Naltrexone that a Doctor can only generalize about dose sizes and then you have to find out for yourself depending on how you feel and perform, your blood tests and your physical examinations and scans. What’s best for other people may not be best for you”.

Most people probably start with 1.5 mgs and then increase over a couple of weeks or a month. (According to Dr. De Meirleir, an ME/CFS specialist, starting doses in ME/CFS can be as low as 0.5 mg. and end up being 5 mg. or more.) In general he finds that 1.5 mg. isn’t enough and 6 mg. is too much and that most people end up taking from 3-4.5 mgs. a day.. He suggests that patients decrease and then increase their dose every few months to check that their requirements for the drug haven’t changed.

If you’re on narcotic pain drugs, do not take LDN until the drugs are out of your system. If you have Hashimoto’s disease, consult with your doctor and start off low.

How Long To Take LDN To Know If It’s Working

Longer than you may think; Jarred Younger Ph.D. stated that it can take 8-10 weeks to determine if you will respond to the drug. Don’t stop taking it before then.

Possible Side Effects

Side effects are usually reported to be minimal but some patients can have a great deal of difficulty with this drug. By starting the dosage off low and going slow many patients can tolerate dosages that would otherwise be intolerable.

Side effects can include priapism (prolonged erections), sleep dysfunction (at least in the beginning) and weight loss. In general side effects are described as ‘mild’ with few issues occurring even with much the higher naltrexone doses used in addiction and alcoholism.

Health Rising LDN Blogs


An impressive grassroots effort has sprung up on the web around LDN:


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