Last Updated on July 30, 2026

Current research suggests that naltrexone has a low risk of liver injury at standard doses. A licensed clinician, at Sunnyside Med or otherwise, can help you determine whether it’s an appropriate option based on your liver health, medical history, and overall treatment goals.

You’re researching naltrexone because you want to drink less. Maybe your doctor mentioned it, or maybe you found it while looking into options on your own. Either way, it doesn’t take long before you run into a warning about naltrexone liver safety.

If you’re already worried that alcohol is harming your liver, taking a medication associated with the same risk might feel a little backwards.

The concern is understandable, but it also deserves necessary context. Many worries about naltrexone liver safety originate from older research, which used much higher doses than doctors prescribe today. At the current standard dose used for alcohol-related treatment, the evidence paints a much more reassuring picture.

In this article, we’ll walk through what researchers know about naltrexone liver safety, who should be cautious, and how doctors monitor liver health while you’re taking it.

Where the Concerns About Naltrexone Liver Safety Came From

The concern about naltrexone and the liver didn’t come from nowhere. In early clinical studies, researchers tested naltrexone at doses much higher than the standard 50 mg daily dose used today. At those very high doses, some participants developed elevations in liver enzymes, prompting the FDA to include a boxed warning (formerly called a black box warning) about possible liver toxicity.

As additional research accumulated, the picture changed. Studies using standard therapeutic doses did not show the same pattern of serious liver injury. In 2013, the FDA removed the boxed warning (Kee et al., 2025).

That doesn’t mean liver health is irrelevant. Naltrexone still carries warnings about use in people with acute hepatitis or liver failure, and clinicians may monitor liver function depending on a person’s medical history. But the evidence that prompted the original boxed warning came from doses far higher than those prescribed in practice today.

The changing evidence has led some experts to question whether fear of liver toxicity has persisted longer than the data justify. In 2025, the Journal of Hospital Medicine included routine avoidance of naltrexone in patients with liver disease in its “Things We Do for No Reason” series, arguing that the available evidence supports a more individualized approach rather than avoiding the medication across the board (Kee et al., 2025).

What the Current Research on Naltrexone Liver Safety Actually Shows

Across multiple studies involving different patient populations, researchers have found little evidence that standard-dose naltrexone causes clinically significant liver injury.

A 2024 retrospective study of patients with cirrhosis found no cases of drug-induced liver injury after starting naltrexone, including among patients with decompensated cirrhosis (Thompson et al., 2024, JHEP Reports). Because this was an observational study rather than a randomized trial, it cannot prove that naltrexone is safe in every situation, but it provides reassuring real-world evidence.

Similarly, a 2022 study published in Hepatology Communications found no evidence of hepatotoxicity (liver damage) among patients with underlying liver disease, including compensated cirrhosis (Ayyala et al., 2022). The authors noted that more research is still needed in people with advanced decompensated liver disease.

Evidence from randomized trials points in the same direction. In a secondary analysis of a clinical trial involving adults with very heavy alcohol use, extended-release naltrexone was not associated with higher rates of liver enzyme elevations than placebo (Vutien et al., 2023, Journal of Addiction Medicine).

The NIH’s LiverTox database reaches a similar conclusion. Mild increases in liver enzymes can occur during treatment, but clinically apparent liver injury is rare, and rates of liver enzyme elevations are similar to those seen with placebo in clinical trials.

Together, these studies suggest that the liver toxicity signal seen in the earliest high-dose studies has not been observed with standard therapeutic dosing.

The More Urgent Liver Safety Risk

When people worry about naltrexone and the liver, it’s easy to lose sight of the bigger picture.

Heavy drinking itself is a well-established cause of liver disease. Over time, alcohol can contribute to fatty liver disease, alcohol-associated hepatitis, fibrosis, and cirrhosis. The risk generally increases with both the amount of alcohol consumed and the duration of drinking.

By comparison, the available evidence suggests that standard-dose naltrexone carries a low risk of clinically significant liver injury. That doesn’t mean liver health isn’t important, but that the medication’s potential risks need to be weighed against the very real risks of continuing to drink more than you’d like.

One person on Reddit said, after successfully cutting back: “My liver numbers actually got better after I started naltrexone, because I was drinking less.”

Who Should Actually Be Cautious

Concerns about liver safety don’t apply equally to everyone. However, there are situations where naltrexone may not be appropriate, and others where it can often be used safely with medical supervision.

Acute hepatitis or acute liver failure: People with active liver inflammation or acute liver failure generally shouldn’t start naltrexone until they’ve been evaluated by a clinician.

Mild or moderate liver enzyme elevations: Elevated levels don’t automatically rule out naltrexone, but they do deserve careful consideration. Many clinicians prescribe the medication with appropriate monitoring after evaluating the underlying cause of the enzyme elevations, your overall liver health, and the potential benefits of reducing alcohol use.

Fatty liver disease: Fatty liver alone generally isn’t considered a reason to avoid naltrexone, and current evidence hasn’t shown that standard therapeutic doses worsen fatty liver disease.

Opioid medications: This is one of the most important safety considerations. Because naltrexone blocks opioid receptors, taking it while using opioid medications can precipitate sudden withdrawal. Your clinician will review your current medications carefully before prescribing.

Deciding whether naltrexone is appropriate isn’t based on a single lab value or diagnosis. It’s based on your overall health, your medical history, and a conversation with a qualified clinician.

Navigating Naltrexone with Sunnyside Med

Medication is only one part of changing your relationship with alcohol. Having support throughout the process can make it easier to stay consistent, manage side effects, and build new habits over time.

Sunnyside Med uses a gradual ramp-up protocol designed to help reduce early side effects, with your clinician guiding your dosing schedule based on your individual needs. 78% of Sunnyside Med members achieve a meaningful reduction in drinking (among active members with 50% or more app engagement). Individual results vary.

Every application is reviewed by a licensed clinician, who evaluates your medical history, current medications, and any factors—including liver health—that could impact your eligibility.

Importantly, Sunnyside also combines medication with other tools that support long-term change, including:

• Drink tracking
• Personalized goal-setting
• Progress analytics
• Seven-day-a-week text coaching
• A private member community
• Educational resources.

Questions about naltrexone telehealth options are worth discussing with a provider, especially if you’re looking for ongoing support rather than a prescription alone.

If concerns about naltrexone liver safety have kept you from exploring treatment, they’re worth discussing with a clinician rather than letting an outdated warning decide for you. Sunnyside Med connects eligible members with licensed clinicians who review each application individually. They can help determine whether naltrexone is an appropriate option for you.

If naltrexone liver safety has been the thing holding you back, clear answers are one step away. The process is 100% online, with no waiting rooms. See if you’re eligible with a two-minute quiz.

Frequently Asked Questions (FAQ): Naltrexone Liver Safety

Does naltrexone damage your liver?

At the standard doses prescribed for alcohol use disorder, current evidence suggests naltrexone has a low risk of significant liver injury. The medication has been FDA-approved for alcohol use disorder since 1994. Studies have found that severe liver toxicity seen in early high-dose research has not been observed with today’s standard therapeutic dosing.

Can I take naltrexone if I have fatty liver?

Fatty liver disease alone generally isn’t considered a reason to avoid naltrexone. Current evidence hasn’t shown that standard therapeutic doses worsen fatty liver disease, though your clinician should review your medical history, liver health, and lab work before deciding whether the medication is appropriate for you. Consult them before beginning any medication.

Why was the naltrexone boxed warning removed?

The FDA removed naltrexone’s boxed warning about liver toxicity in 2013. The original warning was based on studies using doses much higher than those prescribed today. As additional research accumulated, the evidence showed that serious liver injury was not occurring at standard therapeutic doses.

Do I need liver function tests before starting naltrexone?

It depends on your medical history. Many clinicians obtain baseline liver function tests, particularly for people with a history of heavy drinking or known liver disease. Current expert guidance suggests that testing and follow-up monitoring should be individualized.

Is naltrexone safe if I already have elevated liver enzymes from drinking?

Mild or moderate elevations don’t automatically rule out naltrexone. Research has found the medication can often be used safely in people with underlying liver disease when monitored appropriately. If your liver enzymes are elevated, your clinician will consider your lab results, overall health, and drinking history before deciding whether naltrexone is an option.

Naltrexone is a prescription medication. This article is for educational purposes only and should not be considered medical advice. Every Sunnyside Med prescription is based on an evaluation by a licensed clinician.

Sunnyside Med is the Perfect Companion for Your Naltrexone Journey

Sunnyside is the #1 mindful drinking app. Since 2020, we’ve been honing our harm-reduction approach and have helped over 400,000 people cut out 22 million drinks from their baseline habits. 96.7% of our members report success in drinking less. In a third-party study, our approach reduced weekly drinking by 33% after 12 weeks. 

Think of Sunnyside as the front door for anyone who wants to change their relationship with alcohol. If you want to drink less, we can help you get there. If you want to eventually quit, but want to take a gradual approach, we can make that happen.

When you sign up for Sunnyside, you’ll take a quick 3-minute quiz, then hop into the app. It’s as simple and quick as that. 

We’ll give you weekly plans to gradually reach your drinking goals, and we’ll provide nudges, coaching, exercises, and advice to help you get there. 

We have daily tracking and journaling tools, including the option to chat with a real human coach at any time. And our state-of-the-art analytics help you track your progress over time. 

If you choose to stop taking naltrexone, the Sunnyside app remains a tool you can keep using to maintain your healthy habits. 

Everyone who signs up for Sunnyside gets a free 15-day trial. After that, the subscription is $8.25/month.

Whether you’re currently taking naltrexone or just doing some research on alcohol moderation, we’d love to have you sign up for our 15-day free trial today.