Do Paxil and Wellbutrin cause weight loss? 

Do Paxil and Wellbutrin cause weight loss? 

Paxil (Paroxetine) and Wellbutrin (Bupropion) may or may not help you lose weight. If we look at the two antidepressants and their relationship with weight loss, we find Wellbutrin more closely linked with it. It is, in fact, prescribed for the treatment and management of depression comorbid with obesity. 

Paxil, on the other hand, is a selective serotonin reuptake inhibitor. This class of antidepressants is actually known for causing weight gain as a side effect. So, there are a few weight-related possibilities:

  • You may end up losing weight because of Wellbutrin. This is common when a low dose of Paxil is combined with the standard dose of Wellbutrin. 
  • You may not experience any weight loss or weight gain. If Paxil makes you gain a few pounds and Wellbutrin tries to counteract that effect, you may not experience any weight change.
  • You may gain a few pounds. Paxil is known for weight gain, but Wellbutrin may not work that well in some individuals to counteract it and it may not cause any weight loss. Such people can experience Paxil-induced weight gain on this combination. In a few rare cases, Wellbutrin may cause weight gain.

Whatever weight-related change you’re witnessing, talk to your healthcare provider about it. Antidepressants are not that easy to deal with and they are not for everyone. 

If you’re not doing well on the combination of Paxil and Wellbutrin, your doctor may start to taper them off and switch you to another antidepressant or a combination of antidepressants. Make sure you do not start or stop using any antidepressant without your doctor’s approval. 

What does research suggest?

Several research studies have worked on the effects of antidepressants on weight-related changes. In the case of Paxil and Wellbutrin, one causes weight gain more commonly, while the other is known for weight loss and increased energy levels. 

Research studies on Paxil-induced weight-related changes

A clinical trial conducted in 2000 included three antidepressants, Fluoxetine, Sertraline, and Paroxetine and the effects of these meds on body weight were observed. 

The study concluded that Paroxetine caused a significant weight gain in the volunteers, as compared to the other two antidepressants which caused an insignificant increase in body weight (1). 

Another research study suggested that Paroxetine, which is a type of selective serotonin reuptake inhibitor (SSRI), may have a higher likelihood of causing weight gain compared to other SSRIs when used for a long period of time (2). 

However, it’s important to note that more studies are needed to confirm these findings and provide more comprehensive evidence.

In another research study, the findings show that edema, which is swelling caused by excess fluid retention, is a rare side effect of antidepressant use. The study reported two cases where patients experienced rapid weight gain due to edema after using Venlafaxine and Paroxetine (3). 

These adverse effects occurred within 2 to 3 weeks of starting the treatments and completely resolved after the medications were stopped. It is important to note that while edema is a rare occurrence, it can still happen in some individuals taking these antidepressants.

Research studies on Wellbutrin-induced weight-related changes

A recent clinical study divided the volunteers into two groups, one taking Bupropion and the other placebo. The findings showed that the group of patients taking bupropion SR experienced significant weight loss compared to the placebo group. 

The bupropion SR group lost an average of 4.4 kg compared to 1.7 kg in the placebo group (4). The study also found that depressive symptoms improved more with bupropion SR than with placebo, especially in patients with a history of major depression. 

It was observed that regardless of the treatment, a weight loss of 5% or more was associated with an improvement in depressive symptoms. Overall, bupropion SR was well-tolerated by the patients.

In another research study, it was found that Bupropion was more effective than a placebo in helping overweight and obese adult women lose weight. 

The study lasted for 8 weeks, and during this time, the participants who took bupropion experienced greater weight loss compared to those who took the placebo. 

Additionally, those who responded well to bupropion initially continued to benefit from the medication in the following phase of the study. These findings suggest that Bupropion may be a promising option for weight loss in overweight and obese women (5).

Final words

To sum up, Paxil is more commonly linked to weight gain and Wellbutrin to weight loss. It is important to note that none of these medications is intended to use for weight loss. Paxil and Wellbutrin are antidepressants which should only be taken if prescribed by a doctor. 

You won’t have to take two antidepressants together if monotherapy is sufficient for your symptoms. Just make sure you do not start taking any medication without consulting your doctor first. 

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Fava M, Judge R, Hoog SL, Nilsson ME, Koke SC. Fluoxetine versus sertraline and paroxetine in major depressive disorder: changes in weight with long-term treatment. J Clin Psychiatry. 2000 Nov;61(11):863-7. doi: 10.4088/jcp.v61n1109. PMID: 11105740.


Fava M. Weight gain and antidepressants. J Clin Psychiatry. 2000;61 Suppl 11:37-41. PMID: 10926053.


Uguz F. Rapid weight gain associated with edema after use of paroxetine and venlafaxine: 2 case reports. Clin Neuropharmacol. 2014 Jan-Feb;37(1):34-5. doi: 10.1097/WNF.0000000000000012. PMID: 24434531.


Jain AK, Kaplan RA, Gadde KM, Wadden TA, Allison DB, Brewer ER, Leadbetter RA, Richard N, Haight B, Jamerson BD, Buaron KS, Metz A. Bupropion SR vs. placebo for weight loss in obese patients with depressive symptoms. Obes Res. 2002 Oct;10(10):1049-56. doi: 10.1038/oby.2002.142. PMID: 12376586.


Gadde KM, Parker CB, Maner LG, Wagner HR 2nd, Logue EJ, Drezner MK, Krishnan KR. Bupropion for weight loss: an investigation of efficacy and tolerability in overweight and obese women. Obes Res. 2001 Sep;9(9):544-51. doi: 10.1038/oby.2001.71. PMID: 11557835.

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