MEA Summary Review: Low Dose Naltrexone (LDN) in ME/CFS | 02 December 2019

December 2, 2019

Charlotte Stephens, Research Correspondent, ME Association.

This Research Review has been updated to include results from the retrospective study of LDN from Finland that was published in November.
Read the MEA review of Naltrexone and its potential as a treatment for ME/CFS

At the end of October, researchers from Griffith University in Australia published an interesting study that examined the possible therapeutic mechanisms of a drug called ‘Naltrexone’ in ME/CFS patients.

In this summary review, we explain what Naltrexone is, how it works, what it’s used for and why it might be useful as a treatment for ME/CFS.

We also review the latest findings from Australia and Finland.

Key Points

  • Naltrexone is an opioid receptor blocker, traditionally used in the treatment and rehabilitation of alcoholism and opioid addiction.
  • In much lower doses than its traditional use (known as low-dose Naltrexone or LDN), it is used ‘off-label’ (unofficially) in the treatment of a variety of chronic illnesses, including Multiple Sclerosis (MS), Rheumatoid Arthritis, Crohn’s disease, Fibromyalgia, Complex regional pain syndrome (CRPS) and Sjogren’s syndrome.
  • Several studies demonstrate its effectiveness as an anti-inflammatory, pain modulating drug that is useful in many auto-immune type conditions. 
  • The Australian study indicated that Naltrexone is able to restore functioning in Natural Killer cells (a type of immune cell that many studies have found to be dysfunctional in ME/CFS) taken from ME/CFS patients. Larger studies are needed in order to validate these results.
  • In November, a retrospective study from Finland was published which reported a positive level of treatment response and a good safety profile for LDN. This was not a clinical trial however, so we must remain cautious about the results.
  • Dr. Jarred Younger’s team are currently carrying out a clinical trial for the use of LDN in ME/CFS, which is due to complete in summer 2020 (Note: This trial has been suspended – edited 19/06/23).

Comment from Dr Charles Shepherd, Hon. Medical Adviser, ME Association

“This is a small but interesting laboratory-based research study from Australia. However, it would be premature to extrapolate these findings into concluding that naltrexone is likely to be a safe and effective form of drug treatment for ME/CFS.

“We have received very mixed feedback from people here in the UK who have been using naltrexone – even though it is not licensed for treating M.E. Whilst some people report benefits others do not – possibility because naltrexone can produce a number of side effects that overlap with ME/CFS symptoms.

“We have been exploring the possibility of funding a small clinical trial of naltrexone with a researcher in the UK, but no grant application has been received.

“In the absence of any sound evidence of both efficacy and safety, this is not therefore a drug that could be recommended for use in ME/CFS outside a research unit in our current state of knowledge.”


Please visit the Research section for a complete listing of all the summaries we have available.

News Media Reporting

Retrospective study results from Finland

A November study from Finland examined the medical records of 218 people with ME/CFS who were treated with LDN between 2010 and 2014.

They looked at the self-reported feedback from patients on any improvements or side effects experienced and presented the data. ​

They found that a positive treatment response was reported by 74% of the patients. Mild side effects (insomnia, nausea) were common at the beginning of the treatment. No severe adverse effects were reported and only 7% of patients discontinued LDN due to side effects (most commonly nausea). 

It should be noted, however, that this was not a clinical control trial and so we cannot draw any solid conclusions or recommendations from this, nor determine how much of the response was due to placebo effect. 

The high number of treatment responses, along with the good safety profile observed in this study could prompt the development of clinical control trials in order to confirm the feasibility of LDN as a therapeutic drug for ME/CFS. 

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1 thought on “MEA Summary Review: Low Dose Naltrexone (LDN) in ME/CFS | 02 December 2019”

  1. The clinical trial under Dr. Jarred Younger’s team appears to have been suspended.

    “Recruitment Status : Suspended (Temporarily suspended to focus on other projects. At suspension, no participants were determined eligible and none started the protocol.)”

    The article says the results will be published this summer?

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