Low Dose Naltrexone: Does It Work For Weight Loss and Pain?

If someone gave you a medication that could help you lose weight while treating painful and potentially life-threatening illnesses, would you take it? These are some of the purported benefits of the prescription drug Naltrexone when it is taken in small quantities.

This article offers a comprehensive and objective overview of low dose Naltrexone (LDN) for supporters and skeptics alike. We’ll cover what exactly LDN is, how it works, as well as potential treatments and side effects.

What is Low Dose Naltrexone?

Low dose Naltrexone is pretty much exactly how it sounds—it is a low dose of the FDA approved drug Naltrexone. In high doses, Naltrexone has been prescribed for decades to treat addiction to substances like opioids and alcohol while reducing symptoms of withdrawal. At this level of 50 to 100 milligrams per dose, Naltrexone blocks the euphoric effects of certain drugs and alcohol to reduce cravings and eliminate the need for harmful substances.

In small doses under ten milligrams, however, Naltrexone has an opposite effect as it increases endorphins to boost the immune system and provide relief from pain and inflation. In fact, research has suggested low dose Naltrexone (LDN) has a great deal of potential for treating a wide variety of ailments.


Taking small amounts of various drugs is certainly not a new concept. Microdosing is a simple concept that involves taking far below the recommended dose for a given substance. In the case of LDN, most doses are between three and four milligrams, which is less than ten percent of the standard serving. At this level, LDN is reported to provide a number of benefits beyond helping those with addition.

Does Low-Dose Naltrexone Work?

LDN works by increasing the body’s natural production of endorphins by briefly blocking their effects on the brain. Essentially, taking LDN signals the brain that the body is not producing, and utilizing, endorphins necessary to balance the immune system and create healthy cells. In response, the body produces more endorphins and increases sensitivity to try and capture and use more.

The effect of low-dose Naltrexone typically lasts a couple of hours, during which the body is creating more endorphins in addition to the ones already available. When the low dose of Naltrexone wears off, a rebound happens where the body begins to use the standard endorphins that were already produced in addition to the excess endorphins created because of the LDN. This can aid in regulating the immune system and cell growth which, theoretically, can treat auto-immune and degenerative diseases.

The Benefits of Low-Dose Naltrexone

LDN claims to treat a surprisingly long list of maladies, with some treatments showing more promise than others. The drug has been both individually praised and harshly criticized.

Crohn’s Disease

Crohn’s disease is an autoimmune inflammatory bowel disease affecting around 780,000 Americans. Several studies have been conducted on LDN and Crohn’s disease, as LDN presumably treats autoimmune ailments. In one study, 89 percent of participants experienced positive outcomes with LDN treatment. Two-thirds of participants even entered remission, but it important to note this study only examined 17 individuals.

Other studies have shown low-dose Naltrexone can reduce symptoms of an active Crohn’s disease better than a placebo, and LDN might lead to a reduction in reliance on other drugs to treat the disease. These studies were also fairly small, with 40 and 256 participants respectively. Overall, the evidence in favor of LDN as a treatment of Crohn’s disease is strong, but not definitive.

Pain and Inflammation

 Low Dose Naltrexone

LDN can decrease the pain caused by inflammation by blocking the receptors, also known as the opiate receptors, that feel pain. This makes it a potentially effective treatment for several ailments. This efficacy is similar to opioid but does not have the addictive properties of an opioid. Low-dose Naltrexone works on opiate receptors but is a superior treatment alternative.


Two studies have shown LDN to be effective in treating fibromyalgia, a chronic pain condition that typically does not respond to common anti-inflammatory drugs. Research suggests the drug can reduce pain, fatigue, and stress levels while improving overall mood. LDN likely works as it simultaneous blocks pain receptors and improves immune function and reduces inflammation. However, each study examining LDN used a small sample size (10 women in one, 31 in the other) so further research is needed to confirm this potential benefit.

Rheumatoid Arthritis

A small study of ten patients showed the potential of LDN on diseases that cause inflammation and chronic pain. Each patient treated with LDN reported arthritis relief while medicated and a resurgence of symptoms after stopping LDN treatment. This suggests that even if LDN is effective, it may need to be a lifelong, consistent treatment.

Multiple Sclerosis

Multiple Sclerosis, more commonly known as MS, is another autoimmune disease. MS specifically affects the nervous system and disrupts the flow of information from the brain to the rest of the body. Studies indicate LDN may improve the quality of life of MS patients, but has shown no effect on disease modification.

Helps with CRPS Symptoms

CRPS, or Complex Regional Pain Syndrome, may be treated with the pain-blocking potential of LDN. Again, though, studies are small and this claim is not definitive.

Alzheimer’s and Parkinson’s Disease

Low dose or even larger doses of Naltrexone have been shown to stop the progression of degenerative diseases such as Parkinson’s and Alzheimer’s. It is unlikely treatment can reverse damage already done by these diseases. Additionally, studies supporting these claims have been small and some evidence is largely anecdotal. The potential of LDN to slow these incurable diseases is exciting, but more research needs to be done.


A few studies have reported the benefits of LDN in the treatment of children with autism. One researcher found LDN resulted in improved behavior, increased vocality, and decreased repetitive movements or utterances. Others have shown LDN to improve focus and mood while decreasing hyperactivity in patients.

Post-Traumatic Stress Disorder

11 of 15 PTSD patients reported positive effects of LDN treatment. Most claimed they had a clearer perception of themselves and reality and found increased control.

Decreases Nausea in Trauma Patients

When used in conjunction with morphine, LDN did nothing to decrease the pain of trauma patients. However, it did lower their risk for experiencing nausea.

Help Patients Struggling with Drug Problems

Naltrexone was originally approved and prescribed for treating those with drug addictions. Even in low doses, the medication has been shown to decrease the intensity of withdrawal symptoms and reduce cravings.

Heavy-Drinking Smokers

LDN works similarly in those addicted to drugs, alcohol, and cigarettes—even if an individual has more than one addiction. Studies have demonstrated LDN’s ability to reduce cravings as well as the need to feel the euphoria that may drive someone to drink or smoke.

Effective in Treating HIV/AIDS

LDN claims to treat autoimmune disease, and the HIV/AIDS may be the most well-known in this category. One doctor treated AIDS patients with LDN for seven years and found 85 percent of them had no detectable levels of the virus. Even those who test positive for HIV or AIDS turn to LDN to treat symptoms, as LDN corrects the beta-endorphin deficiency found in most patients.

Fights Cancer

Finally, LDN has been positively associated with treating a variety of types of cancer. The drug works alongside chemotherapy and radiation to reduce tumor size by making growths more susceptible to cancer-killing cells and endorphins while increasing production of these helpful cells. One study reported a 75 percent size reduction in the tumors of over 100 patients, while others who were given grim prognoses are still alive and well.

Low Dose Naltrexone Weight Loss

In addition to treating and curing a number of diseases, LDN claims to be an effective way to lose weight. Studies have offered mixed results, with some participants dropping pounds and others reporting no noticeable results. There are a few ways the prescription drug could aid in weight loss efforts, including:

Reduces Insulin Resistance

Full doses of Naltrexone have been shown to decrease insulin levels as it modulates insulin resistance at the cellular level. Particularly in women with high testosterone or PCOS, Naltrexone may be an effective weight loss aid.

May Increase Growth Hormone

In certain patients, Naltrexone can increase the hormone that helps build muscle mass and burn fat. This hormone decreases as weight is gained, making Naltrexone a potential solution for obese individuals.

Modulates Appetite

Weight loss may seem difficult, but it is really a simple equation of calories in versus calories out. Eating less than you burn in a normal day will result in weight loss while eating more leads to weight gain. Naltrexone potentially works by regulating the signals between your brain and your appetite. Essentially, the prescription helps your brain tell your body to eat only as many calories as you typically burn instead of sending constant hunger signals. Eating less can then lead to weight loss and a healthier metabolic system.

Anti-Inflammatory Agent

Inflammation can cause chronic pain and discomfort, but it can also cause hormonal changes that make it difficult to lose weight. Most studies on LDN and inflammation have examined patients with chronic pain, but the medicine may provide an extra benefit in addition to pain relief as it makes weight loss simpler.

May Help Improve Sleep & Sleeping Patterns

Diet and exercise alone are not always enough to achieve a slim figure. Sleep plays a huge role in weight loss and muscle recovery. Research has shown Naltrexone is effective in regulating sleep patterns of patients with sleep apnea. Anecdotal evidence also suggests LDN can help users fall and stay asleep when taken before bed.

The Low Dose Naltrexone Side Effects

Not many adverse side effects have been linked to use of LDN; however, the drug has also not been tested for long-term safety. The most commonly reported side effect is vivid dreams or nightmares, especially during the first few weeks of use. Some patients also report difficulty sleeping, but this usually subsides in a few days. Taking the drug in the morning seems to eliminate both effects altogether.

Other, less reported side effects include pain, vomiting and/or diarrhea, headache, fatigue, loss of appetite, and changes in mood. The warnings that accompany Naltrexone seem to be inconsequential when the medicine is taken in low doses, and it appears LDN is generally safe for most people.

One thing potential users should be aware of is the way to acquire LDN. Naltrexone is only available as a prescription drug and cannot be purchased over the counter, at drug stores, or through online retailers. In fact, it is illegal to sell the drug to an individual without a prescription. Talking with your doctor is the best way to determine if Naltrexone, in any dose size, can be an effective treatment for you. You can also discuss potential side effects, risks, and benefits with your physician before asking for a prescription.

The Bottom Line on Low Dose Naltrexone

LDN exhibits a ton of potential for providing many benefits. Some studies offer exciting solutions to previously incurable or difficult to treat diseases. Further, LDN can be an affordable treatment method for many and does not appear to have any extreme side effects.

However great LDN’s potential might be, the prescription is still woefully understudied in low doses. Many positive studies include major errors such as low sample sizes, lack of attempts to reproduce results, or failure to control with a placebo group. Further, using Naltrexone in small quantities does not adhere to the original, FDA approved the use of the drug.

LDN should not be completely discounted as a treatment for several illnesses and ailments, but it cannot be viewed as a miracle cure-all to everything that plagues the human body. The medication offers a lot of positive possibilities, but also boasts some claims that appear to be too good to be true. More insight into LDN is needed; that insight will only come through rigorous research, well-crafted clinical trials, and time.