Naltrexone For Weight Loss: Does LDN Cause It? How?

Last Updated: June 24, 2020

Authored by Olivier George, Ph.D.

Reviewed by Michael Espelin APRN

Low dose naltrexone for weight loss may be used by patients who are looking to reduce their body mass. Low dose naltrexone can offer weight loss help through various ways for these patients. Furthermore, it is also significant to understand further the link between naltrexone and weight loss, including factors that may cause this side effect and the possible theories behind them.

Does Low Dose Naltrexone Cause Weight Loss?

Among low dose naltrexone side effects, weight loss is one people can benefit from. Despite naltrexone is primarily used for opiate and alcohol addiction treatment, low dose naltrexone (LDN) shows promise in helping patients to lose extra mass. However, naltrexone for weight loss tends to work more effectively on some patients than others; those patients with damaged metabolisms benefit more from the LDN effect on weight.

How LDN Causes Weight Loss

Several theories exist as to how low dose naltrexone diet pill works. Considering the FDA-approved use of naltrexone, both alcohol and opioids abuse is linked to an increase in body fat in the short-run. During LDN use, patients tend to reduce body mass. Above, there are several theories on how LDN causes losing weight.

Suppressed Appetite

Some patients experience reduced appetite as a side effect while taking naltrexone, also known by the brand name Vivitrol. Therefore, according to this theory, naltrexone weight loss effect stems from the reduction of food intake because of the reduced appetite. A study found that an increase of naltrexone dosage from 25 mg to 200 mg resulted in a reduction of food intake by 30% in obese men participated in the study.

Reduced Insulin Resistance

Research has proven that naltrexone helps to lower insulin levels by 40%, and the link between insulin levels and obesity is quite straightforward. Insulin resistance is one of the primary causes of increased mass in people, especially in hypothyroid patients. Naltrexone HCl for weight loss works by modulating cellular resistance to insulin.

Energy Boost

As many patients report that the drug increases their energy during the day, the enhanced physical activity is a potential outcome of such impact. As a result, users may burn extra calories losing a few pounds.

woman after taking naltrexone hcl for weight loss

Improved Sleep Patterns

Lack of adequate sleep causes inflammation and leads to an increase in the body fat in people according to numerous studies. LDN has been proven to improve sleep quality in patients with sleep apnea, as well as some pain syndromes. In this way, LDN helps to lose weight.

Increase In Growth Hormones

Research has suggested that the medication may increase growth hormones in certain patients. Therefore, low dose naltrexone for weight loss works in these patients because the stimulated growth hormones help not only build and maintain lean muscle mass but also increases the burning of fat.

Increased The Thyroid Hormonal Levels

Naltrexone for weight loss can help increase total triiodothyronine (TT3) levels and improve the conversion of total thyroxine (TT4) to total triiodothyronine (TT3). Furthermore, LDN has been shown to improve the immune system and reduce autoantibodies in some autoimmune condition. These two reasons are why low dose naltrexone is used for Hashimoto’s thyroiditis. Naltrexone helps in weight loss in this case because thyroidal gland destruction combined with autoantibodies results in increased mass in people.

Outcome Of Concomitant Side Effects

Naltrexone use is accompanied by some side effects such as diarrhea, nausea, and vomiting. In these cases, patients find any food not very attractive and are unwilling to enjoying it. If these effects are frequent and severe enough, the loss of the body mass can be observed.

Low Dose Naltrexone For Weight Loss: Who Should Use?

It is recommended that patients taking naltrexone diet pills and LDN find a medical professional to monitor them. Furthermore, they can use it in combination with supplements and other medication for the best results.

Additionally, there are populations who are more and less likely to experience a reduction of their body mass. Among the most vulnerable are:

  • women
  • binge eaters
  • high-dose users
  • overweight individuals or those with obesity
  • those who maintain an inactive lifestyle and practice unhealthy diet

On the contrary, men, low-dose users, normal fit or underweight people, and non-binge eaters can see no or slight reduction in the body mass.

Naltrexone HCl For Weight Loss: Affecting Factors


The amount of body mass that a patient loses during naltrexone weight loss treatment is directly related to the dosage. A large 100 mg ReVia dosage could be as much as 2 times more effective than a 50 mg dose. Moreover, it is also true that body mass loss occurs within a specific dosage range and diminishes outside that range.

low dose naltrexone dosage for weight loss

Individual Factors

The amount of body mass a patient loses while taking the drug is also subject to some individual factors such as genetics, body size, exercise, and dietary intake. Body size, including the composition of muscle and the amount of fat, is the first determining factor in this case. The greater the dosage one is taking relative to their body size, the more likely they are to experience low dose naltrexone weight loss. Secondly, individuals with the G allele of the A118G polymorphism of the OPRM1 gene have greater therapeutic benefit from Vivitrol alcohol treatment. Simultaneously, it is suggested that individuals with this polymorphism may benefit more from low dose naltrexone for weight loss as well.

Duration Of Use

The cumulative duration of LDN use may dictate how much body fat someone burns. Patients who have taken low dose naltrexone for weight loss for only two weeks are less likely to notice any considerable changes. However, moderate to long term usage of naltrexone HCl for weight loss is far more likely to yield better results as compared to short-term use. Still, some patients have reported no changes in their body mass even after long term use.

Co-Administered Substances

Patients taking Vivitrol together with other drugs or supplements should be aware that these substances may affect the number of kilograms lost. Naltrexone as a weight-loss drug may be used with supplements, but this should be under the strict supervision of a doctor. On the contrary, drugs such as Zyprexa, which is an antipsychotic, may cause someone’s body mass to increase if used in combination with LDN.

LDN And Weight Loss: What To Remember

Low dose naltrexone is used for weight loss because of its resulting side effect on body mass. However, not all patients stand to benefit from this treatment due to factors such as genetics, diet, body composition, length of use, and other co-administered substances. Furthermore, naltrexone HCl for weight loss can have other general side effects, just like other drugs. Professional help in case of severe symptoms is required. While one can find substance treatment by themselves, there are facilities which can aid as well. For example, drug rehabilitation centers offer full support in terms of physical and mental health.

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Published on: June 7th, 2019

Updated on: June 24th, 2020

About Author

Olivier George, Ph.D.

Olivier George is a medical writer and head manager of the rehab center in California. He spends a lot of time in collecting and analyzing the traditional approaches for substance abuse treatment and assessing their efficiency.

Medically Reviewed by

Michael Espelin APRN

8 years of nursing experience in wide variety of behavioral and addition settings that include adult inpatient and outpatient mental health services with substance use disorders, and geriatric long-term care and hospice care.  He has a particular interest in psychopharmacology, nutritional psychiatry, and alternative treatment options involving particular vitamins, dietary supplements, and administering auricular acupuncture.


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