What Is Low-Dose Naltrexone (LDN) And What Is It Used For?

What Is Low-Dose Naltrexone (LDN) And What Is It Used For?

Low-dose naltrexone (LDN) is a treatment for chronic pain, autoimmune system disorders and weight loss. Unlike other treatments, low-dose naltrexone doesn’t present a risk for addiction or abuse.

Chronic pain is one of the most common health conditions in the US. The CDC estimates that chronic pain affects over 1/5th of the adult population. An abnormal immune system is often to blame.

Low-dose naltrexone may also be a viable treatment for cancer, depression, PTSD and diabetes. LDN has few side effects, can significantly improve quality of life and is cost affordable.

Naltrexone vs. Low-Dose Naltrexone: Explained

The FDA originally approved naltrexone in 1984. At the time, doctors used large amounts of naltrexone to treat opioid addiction. A standard dose ranged anywhere from 50 to 100 mg per day.

In the years since its discovery, doctors have learned that small doses of naltrexone can be therapeutic for specific diseases and disorders.

What is a low dose of naltrexone? In 1985, a New York City physician found that only 3 mg of naltrexone per day was an efficient treatment for HIV patients. Some doctors have seen pain reduction from as little as 0.1 mg/day.

What Does Low-Dose Naltrexone Do?

Naltrexone exerts its effects via the opioid system. The opioid system includes endogenous compounds like endorphins and enkephalins. These compounds activate mu, delta, and kappa opioid receptors.

The opioid system has many functions. One of its functions is regulating pain. It also controls reward, which is why drugs that act on the opioid system can lead to addiction.

Pain is part of the natural immune response. So, it should be no wonder that endorphins, enkephalins, and the receptors they interact with play a role in immunity.

Naltrexone’s chemical makeup is virtually identical to a particular enkephalin — Opioid Growth Factor (OGF). When naltrexone binds to opioid receptors, it de-activates them.

De-activating opioid receptors leads to an increase in endogenous endorphins and enkephalins. Deactivation also causes cells to up production of opioid receptors.

These two actions improve the opioid system’s function. Specifically, naltrexone’s mechanism of action modulates cytotoxic T cell levels. These immune cells are linked to inflammation and pain.

Low-dose naltrexone also interacts with microglia cells in the brain and spinal cord. Microglia are specialized cells that act as a clean-up crew, sweeping away damaged neurons and getting rid of infected cellular waste.

Abnormal microglia levels can lead to inflammation and neuronal death. Increased activation of receptors on microglia is further associated with chronic pain and autoimmune disorder pathologies.

Is Low-Dose Naltrexone Safe?

LDN is very safe. In fact, people taking LDN have rated it even more tolerable than a placebo. The most common side effects from taking LDN are mild constipation, changes in dreaming and mild headaches.

You may be wondering: If naltrexone acts on the opioid system, why isn’t it addictive? Unlike addictive drugs, naltrexone doesn’t activate opioid receptors. Instead, it acts as an opioid receptor antagonist, meaning it reduces feelings of reward and can even counteract the effects of addictive substances.

Conditions Low-Dose Naltrexone Can Treat

It’s been nearly 20 years since researchers started looking into the benefits of low-dose naltrexone. In that time, scientists have uncovered dozens of conditions that may benefit from LDN.

Here are some of the significant conditions research has shown LDN may be able to treat:

Chronic Pain

Fibromyalgia is a chronic pain condition. It impacts the musculoskeletal system and, along with pain, leads to extreme exhaustion and insomnia. Two clinical trials have shown that LDN is efficacious for people with fibromyalgia.

In the most recent study, 57% of fibromyalgia patients experienced significant pain reduction from LDN. 70% of patients studied experienced improvements in pain symptoms by the end of the treatment period.

Autoimmune Disorders

Autoimmune disorders encompass a wide variety of diseases. Crohn’s disease, HIV/AIDS, Multiple Sclerosis (MS) and Hashimoto’s are conditions resulting from an abnormal immune system response.

Crohn’s disease is a disorder of the digestive system caused by increased inflammation. Multiple studies have found that LDN can reduce Crohn’s symptoms, including pain. Objective studies have also found that low-dose naltrexone reduces biological markers of Crohn’s severity and inflammation.

Studies on LDN’s effect on HIV/AIDS have been ongoing since the 1980s. A few years ago, Nigeria’s equivalent of the FDA approved a low-dose naltrexone medication for use in HIV patients.

LDN has also been shown to reduce the frequency of MS attacks. 99% of a population of 400 Multiple Sclerosis patients experienced fewer MS attacks while undergoing low-dose naltrexone therapy.

Hashimoto’s is an autoimmune disorder in which the immune system creates antibodies that attack and damage the thyroid which leads to chronic inflammation of the thyroid. Many patients have observed improved markers while taking low-dose naltrexone.


Non-clinical findings suggest that low-dose naltrexone may help treatment-resistant cancer patients. In a follow-up with 354 LDN-treated cancer patients, over 24% of participants experienced a 75% or more reduction in tumor size.

Other Conditions

Scientists have further implicated low-dose naltrexone as a treatment for many other conditions, from the common cold to emphysema. Research shows that LDN may be an effective therapy for:

  • Weight loss
  • PTSD
  • Major depressive disorder
  • Bipolar depression
  • Diabetes

LDN may boost energy profiles and is widely used in weight loss. Because the opioid system deals with reward, using low-dose naltrexone alongside diet and exercise may aid with weight loss.

Is LDN the Treatment for You?

Whether you want to reduce pain, lose weight, support thyroid function, improve depression or consider an adjunct to cancer treatment, LDN may be the treatment you’re searching for. Consult your doctor. If low-dose naltrexone is appropriate for you, your doctor can send a prescription to our Houston pharmacy / Sugar Land pharmacy location. Shipping is always free.