Naltrexone (LDN)

Available Dosage Strengths

1.5 mg | 3 mg | 4.5 mg

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Product Overview

Description

Low Dose Naltrexone (LDN) refers to naltrexone hydrochloride in doses ranging from 0.5 mg to 4.5 mg, significantly lower than the standard 50–100 mg dosage used for opioid or alcohol dependence. In low doses, naltrexone has been shown to exhibit immunomodulatory and anti-inflammatory effects, and it can be compounded into capsules.

Under guidance from your healthcare provider, LDN can be considered as an adjunct in conditions such as:

Autoimmune diseases (e.g., multiple sclerosis, Hashimoto’s thyroiditis, rheumatoid arthritis)
Chronic pain syndromes (e.g., fibromyalgia, complex regional pain syndrome)
Inflammatory disorders (e.g., Crohn’s disease)

Mechanism of Action

There are several potential pathways that may explain the activity of low-dose naltrexone, although further studies are needed to fully understand the mechanism of action. The following are potential pathways of activity:

Opioid Receptor Modulation

LDN may temporarily block opioid receptors (especially μ-opioid receptors) for a few hours.

This transient blockade can lead to a rebound increase in endogenous endorphins and enkephalins when the drug is cleared.

Higher levels of endorphins may enhance immune system regulation and reduce pain perception.

Toll-Like Receptor 4 (TLR4) Antagonism

Naltrexone acts as a non-specific antagonist of TLR4, found on microglia in the CNS.

By inhibiting TLR4, LDN reduces the release of pro-inflammatory cytokines (e.g., TNF-α, IL-6).

This may help to reduce neuroinflammation, often implicated in chronic pain and autoimmune disorders.

Immunomodulation

LDN is thought to restore T-regulatory cell function and normalize Th1/Th2 balance, critical in autoimmune disease regulation.

May inhibit abnormal B-cell activity and reduce autoantibody production.

Adverse Reactions

Common

Vivid dreams or insomnia (often resolves after 1–2 weeks)
Headache
Nausea
Fatigue
Anxiety or restlessness

Contraindications & Precautions

Contraindications:

Current opioid use: LDN may precipitate opioid withdrawal and block opioid analgesia.
Known hypersensitivity to naltrexone hydrochloride or its excipients.

Precautions:

Liver disease: Though rare at low doses, monitor liver function if using long term or in patients with hepatic impairment.
Autoimmune flare risk: Temporary symptom worsening may occur during immune modulation.
Use caution in:
Patients with major depressive disorder (monitor mood)
Pregnant or lactating individuals (safety not well established)

Storage

Store at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F). Keep in a tight, light-resistant container, in a cool, dry place. Protect from moisture and heat.

References

Younger J, Noor N, McCue R, Mackey S. “Low-dose naltrexone for the treatment of fibromyalgia: findings of a small, randomized, double-blind, placebo-controlled, counterbalanced, crossover trial.” Arthritis Rheum. 2013;65(2):529-538. https://pubmed.ncbi.nlm.nih.gov/23359310/
Smith JP, Stock H, et al.“Low-dose naltrexone therapy improves active Crohn’s disease.”Am J Gastroenterol. 2007;102(4):820–828. https://pubmed.ncbi.nlm.nih.gov/17222320/
Brown N, Panksepp J.“Low-dose naltrexone for disease prevention and quality of life.”Med Hypotheses. 2009;72(3):333–337. https://pubmed.ncbi.nlm.nih.gov/19041189/
LDN Research Trust (non-profit organization with compiled clinical data and patient reports): accessed August 2025 through: https://www.ldnresearchtrust.org
U.S. National Library of Medicine – DailyMed (Naltrexone HCl official monograph) accessed August 2025 through: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=06ff2d5a-e62b-4fa4-bbdb-01938535bc65

Disclaimer

This information is for educational purposes only. This compounded product has not been reviewed, approved, or evaluated by the Food and Drug Administration for safety and effectiveness. This product is not intended to diagnose, treat, cure, or prevent any disease. No claims are made regarding treatment, cure, or prevention of any disease or condition.

This information may not cover all possible drug information about this product. Call your doctor for medical advice and/or about side effects. You may report side effects to the FDA at 1-800-FDA-1088. A Wells Pharmacy Network pharmacist will be happy to answer any questions. For consultation, please call 1-800-622-4510.