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Naltrexone for weight loss (Revia, Vivitrol)

Naltrexone, a medication prescribed to treat opioid and alcohol use disorder, is sometimes used for weight loss. However, taking naltrexone (Revia) for weight loss can be harmful, especially in those vulnerable to disordered eating and eating disorders. It can also be a sign of an eating disorder like anorexia nervosa or bulimia nervosa, especially in conjunction with other behaviors and symptoms.

 minutes read
Last updated on 
January 18, 2024
Naltrexone for weight loss
In this article

What is naltrexone?

Naltrexone is a prescription drug approved by the Food and Drug Administration (FDA) for the treatment of opioid addiction and alcohol addiction. It is also sold under the brand names Revia and Vivitrol, the latter of which is an intramuscular extended-release formulation.1,2,3

Revia and generic naltrexone, which come in pill form, are typically prescribed for alcohol use disorder or alcoholism, while Vivitrol is approved for an addiction to opioids or alcohol.1,2,3

What are the risks of taking Revia for weight loss?

People have begun taking low-dose naltrexone (Revia) or a combination naltrexone/bupropion formula in order to lose weight. Naltrexone/bupropion has been FDA-approved for weight loss in some patients, whereas naltrexone on its own has not been approved and is considered off-label.4 But there are risks associated with taking Revia for weight loss or preventing weight gain.

Taking Revia for weight loss can negatively affect your physical and psychological health, especially for those with a history of dieting. This is because dieting is a risk factor for disordered eating and developing an active eating disorder. In fact, research has shown that about one-quarter of individuals who engage in severe dieting develop an eating disorder.5 And although dieting on its own doesn’t directly cause an eating disorder, it can increase the likelihood of developing one, especially in those who are predisposed. 

You should always consult your doctor, and your medical team, before taking medication for weight loss. Trying to lose weight quickly by taking Revia or other medications can cause a host of side effects and health risks.


Naltrexone side effects and health risks

Common side effects of naltrexone use may include:1,2

  • Nausea and vomiting
  • Dizziness
  • Sleepiness
  • Sleep disturbances
  • Muscle cramps and joint pain
  • Headache and toothache
  • Flu-like symptoms
  • Anxiety and irritability
  • Constipation or diarrhea

Severe adverse effects of taking Revia may include:1,2

  • Depression
  • Hallucinations
  • Pneumonia
  • Confusion
  • Blurred vision
  • Dangerous allergic reaction, including swelling of mouth or tongue, chest pain, trouble breathing, and rash
  • Hepatitis or liver damage, including dark-colored urine and jaundice
  • Injection site reactions, including severe pain, tissue death, blisters, lumps, or open wounds

Can you overdose on naltrexone?

Naltrexone overdose is not common, with even high doses causing relatively benign symptoms.5 However, the real risk of naltrexone, aside from dangerous weight loss and disordered eating potential, is that of overdosing on opioids.1

Since naltrexone blocks opioid receptors, people taking this prescription medication are at risk of overdose if they relapse on heroin or a prescription opioid like Vicodin, Percocet, or other chronic pain management medications. This is because they may take a much higher dose in an attempt to overcome the subdued effect caused by naltrexone. The risk of overdose also increases in someone who has been on Revia or Vivitrol for an extended period of time, effectively lowering their tolerance to opioids during the period of abstinence. Returning to opioid use, especially at their previously used dose, can lead to an overdose.1

If you suspect that someone has overdosed, call 911 immediately and wait for medical personnel to arrive. In the case of an opioid overdose, administer Narcan (naloxone) if it’s available. 

Understanding naltrexone and weight loss

Using a medication like naltrexone or naltrexone/bupropion to lose weight quickly could increase the risk of developing an eating disorder like bulimia nervosa or anorexia nervosa.7

Dieting or using a diet pill like naltrexone alone doesn’t necessarily mean that you have an eating disorder or are engaging in disordered eating, but if other symptoms are present, then it could indicate an issue.

Other symptoms of eating disorders include:10

  • Severe caloric restriction
  • Skipping meals
  • A preoccupation with food, weight, and thinness
  • A pathological drive for thinness
  • Distorted body image
  • Low self-esteem
  • Purging behaviors like laxative use, excessive exercise, and self-induced vomiting
  • Binge eating episodes
  • Feeling profound shame and guilt related to disordered eating behaviors
  • Eating alone or avoiding situations in which food will be present

Naltrexone may be misused by people looking to lose weight thanks to diet culture, which prioritizes weight loss and thinness over health and well-being. Anti-fat bias, or fatphobia, is the intense hatred or fear of people living in larger bodies, and it contributes to the popularity of medications like naltrexone.

Society communicates to us that there is only one “ideal” body type—thinness for women and lean muscle mass for men. However, people of all sizes, shapes, and weights are valid, and there is no such thing as a bodily ideal, though this belief drives many people to engage in disordered eating behaviors and what they perceive as a "healthy diet" in pursuit of thinness. 

Chronic disordered eating can ultimately lead to a clinical eating disorder, which may require formal eating disorder treatment on an inpatient, outpatient, or virtual basis. If you are looking to heal your relationship with eating and movement, professional treatment may be a great option.

While inpatient care may be beneficial for those who need to treat severe symptoms of an eating disorder and need an intensive environment and structure, outpatient treatment can offer flexibility for those who need to schedule treatment around other activities.

Comprehensive care at your fingertips

The most flexible option for comprehensive care is a virtual treatment program, such as the one offered at Within Health.

At Within, we increase your access to care by working with you to create a treatment plan that takes your schedule and needs into consideration. This is especially helpful for those experiencing barriers to care like lack of transportation, lack of childcare, or lack of access to quality, specialized treatment.

Get a free consultation

Disclaimer about "overeating": Within Health hesitatingly uses the word "overeating" because it is the term currently associated with this condition in society, however, we believe it inherently overlooks the various psychological aspects of this condition which are often interconnected with internalized diet culture, and a restrictive mindset about food. For the remainder of this piece, we will therefore be putting "overeating" in quotations to recognize that the diagnosis itself pathologizes behavior that is potentially hardwired and adaptive to a restrictive mindset.

Disclaimer about weight loss drugs: Within does not endorse the use of any weight loss drug or behavior and seeks to provide education on the insidious nature of diet culture. We understand the complex nature of disordered eating and eating disorders and strongly encourage anyone engaging in these behaviors to reach out for help as soon as possible. No statement should be taken as healthcare advice. All healthcare decisions should be made with your individual healthcare provider.


  1. Substance Abuse and Mental Health Services Administration. (2023). Naltrexone. Retrieved May 8, 2023.
  2. National Library of Medicine. (2017). Naltrexone. Retrieved May 8, 2023.
  3. University of Arkansas for Medical Services Psychiatric Research Institute. (2023). What is Vivitrol? Retrieved May 8, 2023.
  4. Yanovski, S. Z., & Yanovski, J. A. (2015). Naltrexone extended-release plus bupropion extended-release for treatment of obesity. JAMA, 313(12), 1213–1214. 
  5. University of Michigan School of Public Health. (2023). The Problem with Dieting: Eating Disorders Affecting American College Students. Retrieved May 8, 2023.
  6. Reece A. S. (2010). Clinical safety of 1500 mg oral naltrexone overdose. BMJ case reports, 2010, bcr0420102871. 
  7. Roeder, A. (2019). A gateway to eating disorders. The Harvard Gazette. Retrieved May 8, 2023.
  8. Stancil, S. L., Adelman, W., Dietz, A., & Abdel-Rahman, S. (2019). Naltrexone Reduces Binge Eating and Purging in Adolescents in an Eating Disorder Program. Journal of Child and Adolescent Psychopharmacology, 29(9), 721–724. 
  9. National Institute of Mental Health. (2023). Eating Disorders. Retrieved May 8, 2023.


What is Revia?

Revia is the brand name for the pill form of naltrexone, which is prescribed to treat alcohol use disorder and opioid use disorder.1,2

Is naltrexone addictive?

No, naltrexone is not addictive and doesn’t cause physiological dependence, which means individuals do not experience withdrawal symptoms if they abruptly stop using it.1

Is naltrexone safe?

Naltrexone is generally safe to take for alcohol use disorder or opioid use disorder, but it may not be safe to take for weight loss purposes, especially since dieting is a risk factor for disordered eating or an eating disorders.

Can you take naltrexone for binge eating?

Research indicates that naltrexone and naltrexone/bupropion may be helpful in treating binge eating disorder, particularly when combined with behavioral therapy and comprehensive eating disorder treatment.8

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Further reading

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