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These medications can help you lose weight by treating cravings and compulsive eating.

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Branded names


Form and dosing

Oral naltrexone typically comes in a tablet form at dosages starting at 50 mg. Dosing instructions vary according to weight, tolerability and other factors and should be discussed with your healthcare provider.

Benefits for weight loss

Reduce appetite

The results are in...

  • How it works

    Although naltrexone is FDA-approved for the the treatment of alcohol and opioid dependence, it is also commonly used by leading specialist obesity clinicians and weight clinics off-label to help aid with weight loss by reducing cravings and compulsive eating behaviors.

  • Common side effects

    Nausea, dizziness, vomiting, stomach cramps, abdominal pain, headaches, and trouble sleeping

  • Common side effects
    • fatigue or low energy
    • difficulty sleeping
    • nervousness and anxiety
    • headache
    • nausea or vomiting
    • joint and muscle pain
    • stomach cramps or pain

What are doctors saying?

“Naltrexone is an off-label option for weight loss which works by treating cravings and compulsive eating.”

— Dr. Rekha Kumar, Chief Medical Officer at Found

When used in combination with other medication

Naltrexone + Bupropion

“Naltrexone and Bupropion is a well studied off-label combination which helps treat binging and cravings and is also helpful for people who feel “addicted to food”

— Dr. Rekha Kumar, Chief Medical Officer at Found

Naltrexone + Bupropion

“Naltrexone and bupropion combination is used together with a reduced-calorie diet and proper exercise to help lose weight and keep it off. This medicine is used in people who are overweight or very overweight and who also have weight-related medical problems.”

— Mayo Clinic

Medical Disclaimers

Naltrexone is only FDA-approved to treat opioid and alcohol use disorders. Prescribing medications are up to a medical provider’s discretion and may not be appropriate for everyone.

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Naltrexone warnings


DO NOT take naltrexone if you are taking ANY opioids or opiate drugs or if you are dependent on opioids or using methadone or buprenorphine, or if you are in opioid withdrawal. If you take opioids/opiates right after stopping naltrexone you may be more sensitive to them (and require lower doses) - which poses a risk of overdose. Please talk to your provider before initiating any amount of opioids/opiates after stopping naltrexone. Do not take this medication if you have a sensitivity to it or any of its components.

Before using naltrexone, tell your healthcare provider about your medical history, especially if you have:

  • kidney disease
  • liver disease (as it may cause liver dysfunction or hepatitis)
  • depression/suicidality
  • current or recent (7-14 days) use of any type of opioid or opiate drugs

This drug may make you dizzy or drowsy or impair your judgment. Please do not drive, operate heavy machinery, or perform any hazardous task until the effects of naltrexone are known to you. For anyone taking diabetes medications, please have a discussion with your prescribing clinician prior to taking naltrexone as your diabetes medications may need to be adjusted as you lose weight. You should wear medical identification stating that you are taking this drug so that appropriate treatment can be given in a medical emergency.

Tell your healthcare provider right away if you experience severe stomach or abdominal pain changes in vision, eye pain, burning or swollen eyes, chest pain, confusion, discomfort while urinating or frequent urination, fever, hallucinations or seeing, hearing, or feeling things that are not there, itching, mental depression or other mood or mental changes or suicidality, ringing or buzzing in the ears, shortness of breath, swelling of the face, feet, or lower legs or weight gain.

DO NOT take naltrexone if you are planning to become pregnant or if pregnant or breastfeeding.

Side effects information

Many people experience no side effects while taking naltrexone. Some of the most common side effects (but not extremely frequent) are:

  • fatigue or low energy
  • difficulty sleeping
  • nervousness and anxiety
  • headache
  • nausea or vomiting
  • joint and muscle pain
  • stomach cramps or pain

Additional side effects include:

  • loss of appetite
  • diarrhea or constipation
  • increased energy
  • increased thirst
  • dizziness
  • skin rash
  • sexual problems in males
  • chills
  • runny nose
  • irritability or feeling down

These symptoms may subside after the body adjusts to the medication.

Drug interactions

As with other medications, naltrexone can interact with certain prescription and non-prescription medications and herbal products, including dextromethorphan, diarrhea medication (such as diphenoxylate), disulfiram, opioid pain or cough relievers (such as codeine, hydrocodone) and thioridazine.

Please consult the pharmaceutical packaging for a full list of side effects, warnings, interactions and additional information.

To report suspected adverse reactions to naltrexone contact the FDA at 1-800-FDA-1088 or

In case of emergencies, please call 911 or go to the nearest emergency room.