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Naltrexone is FDA-approved for alcohol use treatment, but some people use it in conjunction with bupropion for weight loss. While the direct effect of naltrexone on weight loss is limited, there are indirect ways that it can help someone lose weight.
What You’ll Learn:
- Why it’s believed naltrexone can help with weight management.
- The potential side effects of using naltrexone for weight loss.
- What the research says about naltrexone helping users lose weight.
- The indirect way that naltrexone can help people lose weight when it’s taken for alcohol use.
- Reduced empty calories from alcohol
- Improved metabolic functioning for fat burning
- Short-term side effects that reduce hunger
- How naltrexone is paired with bupropion for weight loss.
Naltrexone is effective for alcohol use treatment because it’s an opioid antagonist, which means it binds to opioid receptors to prevent the release of dopamine when alcohol is consumed. While this is highly beneficial for reducing alcohol cravings and alcohol use, it’s also been theorized that naltrexone could have an impact on food cravings and weight loss.
The endogenous opiate system that naltrexone effects has been connected to the regulation of food intake. This connection prompted animal studies that found naltrexone did have an effect on weight loss. But researchers haven’t been able to replicate those findings among humans using naltrexone alone.
However, there has also been research into the use of naltrexone/bupropion (NB) combination therapy. The results for naltrexone/bupropion have been more promising in its ability to help overweight individuals lose weight and keep it off.
What the Clinical Research Says About Naltrexone Side Effects on Weight Loss
There have been a few clinical studies that have examined naltrexone’s direct effect on weight. One randomized, double-blind study involved 60 obese patients. The patients took either a naltrexone 50 mg tablet, 100 mg tablet or a placebo with no medication. The patients took the medication for eight weeks in an outpatient setting.
When looking at the patients as a whole there wasn’t significant weight loss in the naltrexone groups compared to the placebo group. However, when the results were isolated to the female patients it was noted that they did lose close to four pounds in the two-month study period. This still fell short of expectations based on prior animal studies.
Other studies looking at naltrexone on its own had similar findings.
Indirect Effect of Naltrexone on Weight Loss
Although there isn’t strong evidence to suggest that high dose or low dose naltrexone directly causes weight loss like GLP-1 medications, it can make a significant difference in an indirect way for some people.
Reduced Alcohol Use Leads to Weight Loss
If you are using naltrexone to reduce your alcohol consumption or to quit drinking, you may notice that you’re losing weight. Many heavy drinkers often lose 10-20 pounds in the first few months of treatment.
The reason for the weight loss is twofold. First, is the reduction in calories from alcohol that has no nutritional value. Less alcohol = fewer calories being consumed.
The second reason is improved metabolic functioning that leads to more fat burning. When alcohol is consumed fat can’t be burned because the liver prioritizes removing the alcohol toxins from the body. Fat burning is essentially halted for 12-36 hours during the process, and instead calories are stored as fat. Less alcohol in your system = more fat burning.
Naltrexone Side Effects Can Temporarily Cause Weight Loss
Naltrexone side effects aren’t common and are usually short-lived, but early on in treatment they could impact weight due to suppressed appetite. Side effects that can reduce appetite include:
- Nausea
- Constipation
- Vomiting
- Headaches
- Diarrehea
- Stomach pain
Naltrexone side effects are usually mild to moderate, but it could be enough to decrease appetite in the first week to month of taking the medication.
Pairing Naltrexone With Bupropion to Lose Weight
After a few studies in the 1980s were conducted to look at naltrexone’s effect on food intake and eating habits, researchers began using it in combination with other medications to measure the effects. Bupropion was one of those medications.
Naltrexone and bupropion both affect the brain’s reward systems and the hypothalamic melanocortin system. These systems are linked to obesity that’s related to food cravings and mood. Naltrexone and bupropion’s potential for impacting food intake, food cravings and eating behaviors prompted researchers to look at the medications in combination.
Although naltrexone on its own appears to have little impact on weight loss, when it’s combined with bupropion it does have a significant effect. One study from 2011 determined that:
“When used in conjunction with diet and exercise, the naltrexone/bupropion combination may be a useful treatment option for obesity, especially for overweight and obese adults who report difficulty controlling eating behavior and their response to food cravings.”
Another previous study included 419 obese patients over a 24-week period. The goal was to compare naltrexone, bupropion, naltrexone/bupropion combination therapy and a placebo group.
Patients received either:
- 400 mg a day of sustained-release bupropion
- 48 mg a day of immediate-release naltrexone
- NB combination of 16 mg of naltrexone and 400 mg of bupropion a day
- NB combination of 32 mg of naltrexone and 400 mg of bupropion a day
- NB combination of 48 mg of naltrexone and 400 mg of bupropion a day
- Placebo with no medication
In other words, it was a comprehensive study that could determine if the NB combinations worked better than monotherapies or nothing at all. At the end of the 24-week period it was determined that NB combination therapy was more effective than monotherapies. But that’s not all. They continued examining the patients and found that naltrexone/bupropion combination therapy led to gradual and sustained weight loss for more than 48 weeks.
While naltrexone/bupropion combination therapy isn’t currently FDA-approved as a weight loss treatment, it is used off-label due to the promising clinical results.
Whether used in conjunction with bupropion or on its own to reduce alcohol cravings, naltrexone has the potential to make weight loss easier. If you’d like to know more about getting a naltrexone online prescription or need guidance for reducing your alcohol consumption, take the Alcohol Use Assessment. It’s confidential, quick and extremely insightful for anyone who wants an honest assessment of their drinking habits.
