What antidepressant medications may cause weight loss?

Antidepressants are medications doctors prescribe to relieve symptoms of depression. Doctors may also prescribe them for other conditions, such as anxiety, chronic pain, and insomnia.

There are several types of antidepressants, including:

• Selective serotonin reuptake inhibitors: Examples include sertraline (Zoloft) and fluoxetine (Prozac).
• Serotonin-norepinephrine reuptake inhibitors: Examples include venlafaxine (Effexor) and duloxetine (Cymbalta).
• Serotonin modulators: Examples include nefazodone and trazodone (Molipaxin).
• Tricyclic antidepressants: Examples include amitriptyline and imipramine (Tofranil).
• Monoamine oxidase inhibitors: Examples include isocarboxazid (Marplan) and phenelzine (Nardil).
• Atypical antidepressants: These include bupropion (Wellbutrin) and mirtazapine (Remeron).

Each antidepressant type acts differently on the chemicals in your brain and may also affect other body functions.

Antidepressants may cause weight gain or weight loss as a side effect. Not everyone experiences this effect or with the same intensity. Other factors like lifestyle habits and overall health may also have an effect.

Antidepressant medications that cause weight loss

The following antidepressant medications may cause weight loss in some people.

Bupropion

Studies suggest that taking bupropion (Wellbutrin) may result in unintended weight loss for some people. 

A 2016 study found that, on average, people who do not smoke and who took bupropion over 2 years lost 7 pounds (lb) more than people taking other antidepressants.

A 2019 review of the weight-related side effects of different antidepressants found that bupropion was the only antidepressant to result in weight loss after prolonged use.

Experts have theorized that bupropion may stimulate pro-opiomelanocortin cells, which play an important role in your metabolism. In fact, in 2014, the Food and Drug Administration (FDA) approved Contrave, a prescription weight loss drug that contains naltrexone and bupropion.

Healthcare professionals do not advise taking Wellbutrin as a weight loss aid.

Fluoxetine

A 2022 review found that adults with overweight or obesity taking fluoxetine (Prozac) lost, on average, 5.9 lb over the course of treatment. People were also twice as likely to experience side effects, such as nausea, dizziness, fatigue, and insomnia.  

Experts suggest that more research is needed to confirm the effects of fluoxetine on weight changes. Although the medication may cause unintended weight loss during short-term treatment, these effects may differ when taken for a longer period.  

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Duloxetine  

Duloxetine (Cymbalta) may affect your appetite, making you feel less hungry. This, in turn, may result in slight weight loss.

An older study from 2006 and a study from 2010 found that people taking duloxetine experienced slight weight loss over the course of short-term treatments. However, they experienced weight gain when taking the medication for longer periods.

Each person will respond to antidepressant treatment differently. Weight changes may result from several factors, including lifestyle and overall health.

A word of caution

The FDA does not approve or recommend taking antidepressants for weight loss. Taking antidepressant drugs when you do not need them may affect the biochemistry of your brain and how your body functions.

If weight management is your goal, your healthcare professional may recommend prescriptions approved for this purpose.

Other side effects of antidepressants

Antidepressants may have side effects beyond weight changes. Each antidepressant drug may affect your body differently. Some people may experience mild or no side effects, while others may have different concerns when taking the medication.

If side effects affect your quality of life, discuss your options with a healthcare professional. More often than not, adjusting your dosage or changing to a new medication can resolve the problem.

Discontinuing antidepressants or modifying your dose without the help of a doctor is not recommended. Your symptoms may intensify, and you may experience other adverse effects. 

Common side effects of antidepressants may include:

• sexual dysfunction (difficulty having sex or experiencing sexual pleasure)
• drowsiness
• insomnia
• anxiety
• dizziness
• headaches
• dry mouth
• blurred vision
• nausea
• rash
• tremors

Can antidepressants cause weight gain?

A review from 2019 found that weight gain may be a side effect of some antidepressants.

Research from 2021 also found that changes in eating behavior and appetite are common when taking medications for depression. This may lead to weight changes in some people.

A 2016 study comparing weight changes over 2 years of people taking antidepressants found that those taking sertraline (Zoloft) gained more weight than those taking other antidepressants.

Another study from 2020 found antidepressants that may be more likely to cause weight gain include:

• mirtazapine (Remeron)
• amitriptyline
• citalopram (Celexa)
• nortriptyline (Pamelor)
• trimipramine
• paroxetine (Paxil)
• phenelzine (Nardil)

Only some people on these medications experience weight gain. Also, weight changes might not be significant, or they may be temporary.

What to do if you experience side effects from antidepressants?

Consulting a healthcare professional is advised if you experience moderate, persistent, or severe side effects when taking antidepressants. They can help you manage side effects by adjusting your medication, exploring other possible causes, and tailoring the treatment to your needs.

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Summary

Weight changes may be a side effect of antidepressants. Research suggests bupropion may be more likely than other antidepressants to lead to weight loss.

However, each person responds to medication differently. You can work with a doctor to find the best medication option for you.

Taking antidepressants for weight loss is not advised and may lead to adverse effects.