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.

Blocking the receptors that activate the pain-killing opioid pathways or the good feeling producing endorphin pathways wouldn’t seem to be a good thing for these diseases.  Some studies suggest natural pain relievers like endorphins and other substances are low in chronic pain disorders like fibromygalgia and chronic fatigue syndrome (ME/CFS).

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

Feeling Good?

Low dose naltrexone (LDN) works differently than naltrexone. LDN  appears to prompt the opioid and endorphin systems to respond with a vigor – producing more “feel-good” substances.

Blocking the receptors for endorphins and opioids appears to trick the brain into producing more of them. The 4-6 hours or so the drug remains in one’s system is 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 fibromyalgi and similar disorders.

Inflammation Buster?

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. present in chronic fatigue syndrome (ME/CFS) and fibromyalgia.  Recent studies suggesting that neuroinflammation is present in both fibromyalgia and ME/CFS has put a new spotlight on these cells.

Fibromyalgia Neuroinflammation Finding Could Open New Treatment Options

LDN’s ability to block a key receptor (TLR 4) on microglial cells appears to inhibit them from becoming activated and is another good reason to try it in both FM and ME/CFS.


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.

To sum up…

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

LDN may be able to reregulate immune functioning and increase levels of “feel-good” substances such as endogenous opioids and endorphins that may be low in the disorder. LDN’s ability to tamp down microglial functioning could reduce the central sensitization present in these diseases and the fatigue, pain and other symptoms it’s associated with.

Fibromyalgia Low Dose Naltrexone (LDN) Studies

Two small fibromyalgia studies  lead by Jarred Younger suggested low dose naltrexone can significantly help some people 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.  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 may indeed be playing a large role for some  people 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.)

Dextro-Naltrexone – A Better Naltrexone?

Jarred Younger believes a better, a possibly much, much more effective naltrexone may be within reach. Dextro-naltrexone is a different form of naltrexone which may be more effective at reducing neuroinflammation and produces fewer side effects.

Jarred Younger III : Treatments – A Better LDN and the Hunt for Microglia Inhibitors

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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