Inflammation and the immune system
Inflammation is part of many chronic health concerns, from reactive skin to slow recovery and fatigue. Low dose naltrexone (LDN) has drawn interest as a medication that may modulate inflammatory and immune signaling. It was originally developed for entirely different medical purposes.
What is low dose naltrexone?
Low dose naltrexone refers to the use of naltrexone at a small fraction of its standard dose. Full-strength naltrexone was approved by the FDA decades ago for opioid addiction and later for alcohol dependence. At low doses, it is thought to behave differently.
At these doses, naltrexone is described as causing a brief, temporary blockade of opioid receptors. The proposed result is a rebound effect in which the body produces more of its own endorphins and enkephalins. These natural peptides are involved in pain signaling, immune function, cell growth and inflammatory signaling.
How LDN is thought to work
The endorphin effect
LDN binds to opioid receptors for a short period. The body is thought to respond by:
- producing more endorphins, the body's natural pain-relieving chemicals, and
- increasing the sensitivity of opioid receptors (upregulation).
Glial cell modulation
LDN is also being studied for its effect on microglia, the immune cells of the central nervous system. When chronically activated, microglia release inflammatory chemicals associated with pain, fatigue and "sickness behavior." Researchers are investigating whether LDN shifts these cells toward a resting state. This is one reason it is discussed in relation to fibromyalgia, chronic fatigue and central sensitivity syndromes.
Conditions being studied
Clinical studies and patient reports have explored LDN in a range of conditions. The strength of the evidence varies by condition.
Autoimmune conditions
Conditions such as Hashimoto's thyroiditis, Crohn's disease, rheumatoid arthritis and multiple sclerosis involve an immune system that attacks the body's own tissue. LDN is being studied for whether it can modulate this immune response.
Chronic pain and fibromyalgia
Fibromyalgia and some other chronic pain conditions are associated with central sensitization, in which the nervous system amplifies pain signals. Because LDN may influence glial cells, it has been studied as a possible way to reduce this amplification.
Chronic fatigue syndrome (ME/CFS)
ME/CFS involves complex metabolic and immune dysfunction and is difficult to treat. LDN has been explored for its possible effects on immune signaling in this condition. It is not a stimulant.
Skin inflammation
The skin is an immune organ. Conditions such as lichen planopilaris, psoriasis and chronic itching (pruritus) have been discussed in relation to LDN because of its proposed effects on inflammation.
LDN, metabolism and weight
LDN is not a weight-loss drug in the way GLP-1 medications are. Inflammation can interfere with metabolism and is linked to insulin resistance, which is why LDN sometimes comes up in metabolic discussions. A separate combination medication pairs naltrexone with bupropion to target cravings and appetite. That is a different product from LDN.
Gut health
Inflammatory bowel conditions such as Crohn's disease and ulcerative colitis are among the areas where LDN's effect on the immune response in the gut is being studied. LDN does not address structural digestive problems such as acid reflux.
Safety and side effects
LDN is often described as having a favorable safety profile because the dose is low. Commonly reported side effects include:
- Vivid dreams. This is the most frequently reported side effect and is thought to relate to the endorphin rebound during sleep.
- Headaches. Mild, temporary headaches may occur in the early weeks.
Other points that are often noted:
- Opioid medications. LDN blocks opioid receptors, so it should not be used with opioid pain relievers (such as hydrocodone or tramadol). Doing so can trigger acute withdrawal.
- Dependence. Naltrexone is not habit-forming.
- Liver. High-dose naltrexone carries liver-monitoring requirements. Low doses have not been shown to carry the same risk, but liver health is still part of a standard medical review.
LDN vs. standard-dose naltrexone
At standard doses, naltrexone creates a continuous blockade of opioid receptors, which is how it is used for opioid and alcohol dependence. Low dose naltrexone is intended to create a short, pulsatile effect instead. The two uses are distinct.
Frequently asked questions
Can LDN be taken with other medications?
LDN is generally described as compatible with many medications. The major exception is opioid medication. People on immunosuppressants or other specialist-managed medications should review LDN with their treating clinicians.
Is LDN an antidepressant?
No. Some people report changes in well-being, possibly related to endorphins, but LDN is not an antidepressant.
Can you drink alcohol while taking LDN?
At low doses, LDN is not described as causing the same reaction to alcohol as the higher dose used for alcohol dependence. Alcohol itself is inflammatory.
This article is for general educational purposes only and is not medical advice.
