Low-Dose naltrexone tested for long COVID fatigue
NCT ID NCT05430152
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study tested whether low-dose naltrexone (LDN) can reduce fatigue and improve related symptoms in people with post-COVID fatigue syndrome. 160 adults who had confirmed COVID-19 and met criteria for post-COVID fatigue took either LDN or a placebo for 16 weeks. The main goal was to see if LDN significantly lowered fatigue levels.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- low-dose naltrexone (LDN)
- What this could lead to
- If it works, this could offer a new treatment option for people suffering from long-lasting fatigue after COVID-19.
- What could go wrong
- This is a Phase 2 trial, so results are still early. The drug may not prove effective for everyone, and side effects are possible.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 2
Tests whether the treatment actually works, and watches for side effects, in a larger group.
- Participants
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160 people
The number who actually took part.
- Started
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Jan 2024
- Finished
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Feb 2026
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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19 to 69 years
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: 1. Male and female patients ages 19 to less than 70 years 2. Case of SARS-CoV-2 over 3 previously, confirmed by a positive test result or clinical confirmation by a physician 3. Meet the clinical diagnostic criteria for PCFS 4. Agree to maintain any other regular medications at current doses for the duration of the trial (except for essential need of new medication or dose change, as prescribed by a physician) 5. Agree to use effective contraception for the trial duration, as appropriate, if female. 6. The participant resides within the delivery area for the drug as determined by FedEx Clinical Trial Services Exclusion Criteria: 1. Pregnant, planning to become pregnant, or breastfeeding 2. Opioid medications: * Any use within last 15 days, as reported by the patient * During the trial 3. A positive urine test for opioids (only for the first 16 participants) 4. History of alcohol, opioid or other substance misuse 5. Participation in another interventional clinical trial in the last 30 days or planned during the trial period 6. Confirmed ME/CFS or FM existing prior to SARS-CoV-2 infection 7. Allergy to naltrexone or medication components 8. Acute hepatitis, liver failure, or severe kidney failure. 9. Current or recent use of naltrexone in the last 30 days 10. The participant is not an ideal candidate for the study, in the opinion of the investigator, for any other reason (ie. personal or logistic, medication, condition, etc.) that could impact the participant's safety or the results of the study. Opioid Washout Period: Potential participants who are currently taking opioid medications who wish to enrol the study will be instructed they can stop taking opioid medications for 15 days before continuing the screening process. They will be instructed that they should speak with their family doctor before stopping any prescribed medications. Positive Urine Test for Opioids: As regular use of opioid medications is an exclusion criterion, we will do a quality control check with the first 16 participants to test for the presence of opioids in their urine. Any participants with a positive test, will be excluded from the study, and such finding will be discussed at the Trial Steering Committee or DSMB for potential trial modification.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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Women's Health Research Institute
Vancouver, British Columbia, V6H 3N1, Canada
More trials for these conditions
Other studies related to the condition(s) this trial covers.