Does Wellbutrin Cause Weight Gain? Unraveling the Truth About Bupropion's Impact on Your Weight

If you're considering taking Wellbutrin (bupropion) as an antidepressant, you might be wondering how it could affect your weight—will it cause weight gain, weight loss, or have no impact at all? Let's dive into the research and uncover the truth about this popular medication.


Depression is a complex and challenging mental health condition that affects millions of people worldwide. One of the most commonly prescribed medications to treat depression is Wellbutrin, also known by its generic name, bupropion. This antidepressant comes in two forms: Wellbutrin XL (extended-release) and Wellbutrin SR (sustained-release). If you're considering taking Wellbutrin to manage your depression, you might be curious about its potential side effects, particularly whether it can cause weight gain or weight loss. In this article, we'll explore the research on Wellbutrin's impact on weight and provide some clarity on this important topic.

Wellbutrin and Weight Changes

Weight changes are a common concern for people taking antidepressant medications, as some drugs in this category are known to cause weight gain or weight loss. In the case of Wellbutrin, both weight gain and weight loss have been reported as side effects. However, it's important to note that not everyone taking Wellbutrin will experience a change in weight. The likelihood of weight changes varies depending on the individual and the specific formulation of Wellbutrin being taken.

To better understand the relationship between Wellbutrin and weight changes, let's take a look at some statistics from clinical studies on Wellbutrin XL and SR:

  • In studies of Wellbutrin XL, 23% of people taking a dose of 150 to 300 mg per day lost 5 pounds or more. In the same studies, 11% of people gained more than 5 pounds.
  • In studies of Wellbutrin SR, 14% of people taking a dose of 300 mg per day lost more than 5 pounds. At a dose of 400 mg, 19% of people lost more than 5 pounds. In the same studies, a small percentage of people gained more than 5 pounds: 3% taking 300 mg and 2% taking 400 mg.

These statistics demonstrate that while some people taking Wellbutrin do experience weight changes, the majority of individuals do not. Additionally, weight loss appears to be more common than weight gain among those who do experience changes in weight.

The Possible Connection Between Wellbutrin and Weight Loss

The exact reason why Wellbutrin causes weight loss in some individuals remains unclear. However, researchers believe that it may be related to the drug's mechanism of action in treating depression. Wellbutrin works by increasing the levels of dopamine—a neurotransmitter responsible for regulating mood, motivation, and reward—in the brain. Some studies suggest that lower levels of dopamine may be linked to obesity, as the neurotransmitter plays a role in regulating appetite and energy expenditure.

One theory is that by increasing dopamine levels, Wellbutrin may help to suppress appetite and increase energy, leading to weight loss in some individuals. However, more research is needed to fully understand the relationship between Wellbutrin, dopamine, and weight loss.

Wellbutrin as a Smoking Cessation Aid

In addition to its use as an antidepressant, Wellbutrin is also prescribed to help people quit smoking. The sustained-release (SR) formulation of bupropion has been shown to be effective in reducing nicotine cravings and withdrawal symptoms, making it easier for individuals to quit smoking. Interestingly, research has found that people using Wellbutrin SR for smoking cessation are less likely to gain weight after they stop smoking.

A study published in the Journal of Consulting and Clinical Psychology found that participants who took Wellbutrin SR for smoking cessation were significantly less likely to gain weight compared to those who took a placebo. This finding is particularly noteworthy, as weight gain is a common concern for individuals quitting smoking. The study's authors suggest that Wellbutrin's effects on dopamine levels may help to counteract the weight gain typically associated with smoking cessation.

Comparing Wellbutrin XL and Wellbutrin SR

As mentioned earlier, Wellbutrin comes in two formulations: XL (extended-release) and SR (sustained-release). While both formulations are used to treat major depressive disorder, there are some key differences between the two:

  1. Dosing Schedule: The primary difference between Wellbutrin XL and SR lies in their dosing schedules. Wellbutrin XL is an extended-release medication, which means that it is designed to release the active ingredient (bupropion) slowly over time. As a result, Wellbutrin XL only needs to be taken once a day. On the other hand, Wellbutrin SR is a sustained-release medication, which means that it releases the active ingredient at a steady rate throughout the day. This formulation typically requires twice-daily dosing.

  2. Approved Uses: Both Wellbutrin XL and SR are approved by the U.S. Food and Drug Administration (FDA) for the treatment of major depressive disorder. However, Wellbutrin XL has an additional approval for the treatment of seasonal affective disorder (SAD)—a type of depression that occurs with the changing of seasons, usually in the fall and winter. Wellbutrin SR does not have this specific approval, although it may still be prescribed off-label for SAD.


In conclusion, the relationship between Wellbutrin and weight changes is complex and varies from person to person. While some individuals taking Wellbutrin may experience weight gain or weight loss, the majority of people do not experience significant changes in weight. Among those who do, weight loss appears to be more common than weight gain.

The exact reason for Wellbutrin's impact on weight remains unclear, but it may be related to the drug's effects on dopamine levels in the brain. Additionally, Wellbutrin's potential to minimize weight gain during smoking cessation may make it an attractive option for individuals looking to quit smoking.

Ultimately, if you're considering taking Wellbutrin for depression or smoking cessation, it's essential to discuss your concerns about weight changes with your healthcare provider. They can help you weigh the potential benefits and risks of the medication and determine the best course of action for your individual needs.