Lost Weight on Wellbutrin, or Gained? What Studies Show
Wellbutrin is more often linked to weight loss than gain, but some people do gain.
By withClaro Editorial · 2026-11-02 · 4 min read
Clinical section reviewed by Dr. Jason Tan , Consultant Psychiatrist, on October 27, 2026.
Key takeaways In the FDA depression trials, people on bupropion were more likely to lose than gain more than 5 pounds. In a 2024 study of 183,118 people, bupropion had the smallest weight gain of eight common antidepressants, though the differences were small. In 100 r/bupropion threads, about three times as many people said they lost weight as said they gained. Wellbutrin is not prescribed for weight loss, and steady loss you did not expect is worth raising with your prescriber. On this page
What 180 people on r/bupropion said about their weight Can Wellbutrin cause weight gain? How does Wellbutrin compare with other antidepressants for weight? What should you tell your prescriber about weight changes? Wellbutrin (bupropion) is more often linked to weight loss than gain, which sets it apart from most antidepressants, but some people do gain on it. In the FDA's depression trials of the sustained-release form, 14% of people on 300 mg a day lost more than 5 pounds, against 6% on placebo, and 3% gained more than 5 pounds, against 4%.
Weight loss is not a reason to take bupropion, and for some people it is a reason not to. The label says it must not be used by anyone with bulimia or anorexia, now or in the past, because seizures were more common in them.
What 180 people on r/bupropion said about their weight
We read 100 recent threads about weight on r/bupropion, comments included, and 289 people described their own experience. These are people's own accounts, not measured weights, and people with a change to report are more likely to post, so treat the numbers as what change looks like when it happens, not how often. Of the 289, 180 said whether their weight changed: 111 lost weight and 35 gained.
What people reported Of 180 people Lost weight 111 Gained weight 35 No change 24 Weight went both ways over time 10
Of the 89 people who gave a number, the typical change was about 18 pounds, in either direction; our count did not split the amount by whether people lost or gained.
Some changes did not hold. One person on r/bupropion wrote:
I lost 8lbs in the first month but put it all back on
Can Wellbutrin cause weight gain? Medically reviewed by Dr. Jason Tan on October 27, 2026, this section only.
It can for some people, though less often than loss. In the label's short-term depression trials of the sustained-release form, 3% of people on 300 mg gained more than 5 pounds, against 4% on placebo. On r/bupropion, 35 of 180 said they gained. Of the 45 who gained at some point, counting those whose weight went both ways, 16 named a bigger appetite or cravings. Gain, when it happens, tends to build over months, often as appetite comes back with mood. The clinical view:
Weight can change on an antidepressant, and noticing a change early gives you the most options.
In the first weeks, some people lose a little weight because of nausea or a smaller appetite. Gain, when it happens, usually builds over months, though with a few medications it can start within weeks. It varies a lot between people on the same medication.
Several things feed into it: appetite returning as mood improves, cravings, less activity, poor sleep and the medication itself.
What you can do:
- Mention a steady rise at your next appointment, while the change is still small. - Raise weight loss that keeps going, or an appetite that has not come back after the first weeks. ## Why does Wellbutrin cause weight loss?
Mostly through appetite. Unlike most antidepressants, bupropion acts on noradrenaline and dopamine rather than serotonin, and decreased appetite is among its common side effects. The label reports a dose-related drop in body weight in its short-term depression trials of the sustained-release form. In longer trials of the XL form for seasonal depression, up to 6 months, 23% lost at least 5 pounds, against 11% on placebo, and gain was less common than on placebo, 11% against 21%.
How does Wellbutrin compare with other antidepressants for weight?
It sits at the low end for gain, but the differences are small. A 2024 US study used the health records of 183,118 people in eight health systems to compare weight six months after starting one of eight common antidepressants, each against sertraline. By six months only 28% to 41% were still taking their medication, bupropion users the most, which is part of why the differences are small. People who started bupropion gained about 0.22 kg, or half a pound, less than those on sertraline, and had a 15% lower risk of gaining at least 5% of their body weight. The authors themselves call the differences in average weight small.
What should you tell your prescriber about weight changes?
Tell your prescriber what changed, when it started and how much it bothers you, in either direction. There is usually more than one way forward, and the choice is one you make with them, so bring notes rather than a decision. It helps to tell them:
When you started Wellbutrin, your dose and any dose changes. When you first noticed a change, and whether it's still going. Changes in appetite, energy or sleep since starting. Whether your clothes fit differently. Any history of an eating disorder. Stopping on your own to control weight can bring on withdrawal or a return of symptoms.
Download on the App Store Appetite on Wellbutrin can change quickly, and weight follows over weeks. The withClaro app lets you log appetite, energy, sleep and mood each day, linked to your dose, and turns it into a report for your prescriber.
Frequently asked questions Is Wellbutrin prescribed for weight loss? No. The label approves it for depression and seasonal depression. Ask your prescriber before using it for any other reason.
How soon does weight change on Wellbutrin? Appetite can drop in the first weeks, and weight follows over months, if it changes at all. Note your appetite and energy in the first month so you can tell your prescriber when it started.
Does Wellbutrin reduce appetite? For many people it does. Decreased appetite is among its common side effects in the label. If your appetite has not come back after the first weeks, raise it at your next appointment.
Is Wellbutrin better than Zoloft for weight? In the 2024 study, bupropion was linked to slightly less gain than sertraline, about 0.22 kg over six months, a difference the authors call small. Weight is one factor in choosing a medication, not usually the main one; raise it when your prescriber chooses.
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Sources WELLBUTRIN XL (bupropion) prescribing information, US Food and Drug Administration via DailyMed, revised February 2026 Petimar J, et al. Medication-induced weight change across common antidepressant treatments: a target trial emulation study. Annals of Internal Medicine, 2024 Claro articles are for self-monitoring and educational purposes only. They are not a medical device, therapist, or diagnostic tool, and do not replace care from your prescribing clinician. If you are in crisis, contact your care team, emergency services, the Samaritans (UK: 116 123), or the Crisis Text Line (US: text HOME to 741741).