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For Physicians: Learn More about Low-dose Naltrexone

Low-dose Naltrexone or LDN is helping patients suffering from auto-immune and other disease regain their healthy lives. Naltrexone is a class of drug known as an opiate antagonist.  It’s normal use is in treating alcohol dependence behavior modifications, opioids dependence cessation programs, and rapid detoxification from opiate overdose.  The dose used for this purpose is usually 50 and 300 mg daily.  It is a competitive antagonist of opioid drugs at the four types of opioid receptors throughout the entire body.  Receptors didn’t evolve for external opioids, but for our natural endorphins; both excitatory and inhibitory activities.

20% of the population suffers from autoimmune or a chronic disease 65 millions people complain of chronic pain

LDN Research Trust has spent over a decade recording testimonies from physicians, patients, and trusted pharmacists.  As of 2016, Low-does Naltrexone is most commonly being used for Chronic Fatigue, Multiple Sclerosis, Myalgic Encephalopathy, and autoimmune thyroid diseases.  

The TLR-4 receptors are found in immune cells throughout the peripheral tissue, impacting multiple immune mediated disease states, including:

Low-Dose Naltrexone Prescription Form

It is being studied for arthritis, wound healing, and scar formation (preventing hypertrophy).

Many clinicians find it difficult to understand how one drug (50:50 mixture of two different isomers called levo Naltrexone and dextro Naltrexone)  can have a positive effect on all these pathologies;

Endorphin boost 300%

Levo-Naltrexone is an antagonist for the opiate/endorphin receptors

Dextro-Naltrexone is an antagonist for at least one, if not more immune cells

Naltrexone in larger doses of 50-300 mg seems to negate the immunomodulatory effect by overwhelming the receptors, so to work, the dose must be in the range of 0.5mg-10mg, usually maxing at 6 mg in clinical experience.

Suggested Therapy

Types of LDN

Liquid – oral liquid formulation at 1 mg/ml
Capsules – available in strengths ranging from 1.5 mg – 4.5 mg
Sublingual drops – designed for patients who have trouble taking medicine
Cream –   0.5mg/ml available for skin application, helpful for children


Patients who are taking multiple medications and/or herbal medicines should take careful advice from a qualified doctor or pharmacist before starting LDN. Speak with your doctor if you have a medical procedure.

Key Clinical Studies

Low Dose Naltrexone has been the subject of much debate but actually very few clinical trials. Ian Zagon from Penn State University has been studying LDN for over 20 years and conducted many preclinical studies investigating LDN in cancer and in the animal model of MS. He has also been involved in two clinical studies into Crohn’s disease with his colleague Professor Jill Smith from Penn State. These demonstrated a significant improvement in symptoms and in bowel mucosal appearance with LDN treatment. In the RCT, LDN patients were twice as likely to have a 70 point decline in the Crohn’s Disease Activity Index. 78% of the LDN group achieved an endoscopic response compared to 28% with placebo.

Jarred Younger from Stanford University has studied LDN in Fibromyalgia, firstly in a small pilot study and more recently in a yet to be published randomized controlled trial. The pilot study showed significant improvement in symptoms of pain in these patients.

Multiple Sclerosis is one of the areas where LDN has been used the most frequently. There are three published studies, one in primary progressive MS and two on quality of life. The results of two studies was positive with improved quality of life in one and reduced spasm in the PPMS study. The third showed no significant difference between the treatment and placebo groups but found the treatment to be safe. A review of the available studies into LDN and MS was published in 2009. All studies have confirmed the safety of the drug and there is enough positive evidence to merit greater investigation.

Additional references available upon request.

Low-Dose Naltrexone Prescription Form