Low-dose naltrexone (LDN) is an off-label use of the medication naltrexone, typically in doses ranging from 1.5 to 4.5 mg per day. LDN is believed to modulate the immune system and reduce inflammation, potentially providing relief for conditions such as autoimmune diseases, chronic pain, fibromyalgia, and certain types of cancer. It’s thought to work by briefly blocking opioid receptors, leading to increased production of endorphins and other beneficial effects. LDN is often used as an adjunct therapy and should be prescribed and monitored by a healthcare professional.

Low Dose Naltrexone (LDN) 4.5 mg is the highest common dose used in the low-dose range of naltrexone therapy. Like the 1.5 mg version, it is used off-label to support immune function, reduce chronic inflammation, and manage pain, but at a dose that is often considered the “target” or “maintenance” level for many users.

Quick Summary

• Drug Name: Low Dose Naltrexone (LDN)
• Dosage: 4.5 mg (commonly the maximum in LDN protocols)
• Purpose: Immune modulation, anti-inflammatory, and pain management
• Form: Oral capsule (usually compounded)
• Schedule: Typically taken once daily at bedtime

Common Uses (Off-Label)

• Autoimmune conditions (e.g., multiple sclerosis, Hashimoto’s, rheumatoid arthritis)
• Chronic pain syndromes (e.g., fibromyalgia, endometriosis)
• Inflammatory bowel diseases (Crohn’s, ulcerative colitis)
• Neurological conditions (Parkinson’s, ALS)
• Chronic fatigue syndrome, long COVID, and even adjunct support in cancer therapies

How It Works

• Temporarily blocks opioid receptors to stimulate production of natural endorphins
• Endorphins help regulate the immune system, reduce inflammation, and improve mood and pain tolerance

Dosage Information

• Many patients start at lower doses (e.g., 1.5 mg) and titrate up to 4.5 mg as tolerated
• 4.5 mg is often considered the optimal daily dose, but it may vary per individual

Side Effects (Usually Mild)

• Sleep disturbances or vivid dreams
• Headaches
• Digestive upset
• Temporary worsening of symptoms in the first week or two (“healing crisis”)

Important Notes

• Not safe to use with opioid pain medications (can block their effect)
• Must be prescribed and compounded specially, as 4.5 mg tablets are not commercially available
• Always use under guidance from a healthcare professional

1. What is LDN 4.5 mg used for?
LDN 4.5 mg is used off-label to help manage autoimmune diseases, chronic inflammation, nerve-related pain, and conditions like fibromyalgia, MS, and Crohn’s disease.

2. Is 4.5 mg the standard dose for LDN?
Yes. 4.5 mg is often the target or maintenance dose for most people using LDN, though some may feel better at lower doses (like 1.5–3 mg).

3. How is LDN different from regular naltrexone?
Regular naltrexone is used in 50 mg doses to treat addiction. LDN (4.5 mg) is a much lower dose used to support the immune system and reduce inflammation.

4. Can I take LDN 4.5 mg with pain medications?
No. LDN blocks opioid receptors and can interfere with opioid painkillers. Always check with your doctor before starting LDN.

5. When should I take LDN 4.5 mg?
It’s usually taken once daily at bedtime to help boost endorphin production overnight.