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SSRI weight gain statistics 2024

38% of SSRI users report side effects with the most common being weight gain. Compare updated SSRI weight gain stats for Zoloft, Prozac, Paxil, Lexpro, and Celexa here.
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By | Updated on Sep. 3, 2024 Medically reviewed by Josephine Bawab, Pharm.D.
Clipboard with charts: SSRI weight gain statistics 2022

Can SSRIs cause weight gain? | How common is SSRI weight gain? | Zoloft | Prozac | Paxil | Lexapro | Celexa | Other antidepressants | Weight management | FAQs | Research

Selective serotonin reuptake inhibitors (SSRIs) are a class of antidepressant drugs. “SSRIs work by inhibiting the body’s absorption of serotonin, thereby leaving higher levels of serotonin in the brain. The higher levels of serotonin can alleviate the symptoms of depression and anxiety,” explained Dr. David Culpepper, M.D. and clinical director of LifeMD, a direct-to-patient telehealth company.

According to the Centers for Disease Control and Prevention (CDC), 13.2% of adults used antidepressant medications from 2015 to 2018. Of those who took antidepressants, 17.7% were women and 8.4% were men. 

Can SSRIs cause weight gain?

While the use of SSRIs is popular, the side effects aren’t. “One of the most common reported side effects of SSRIs is a light to moderate amount of weight gain,” said Dr. Culpepper. For many SSRI users, this trade-off may be worth it if they can start feeling like their old selves again and decrease depressive symptoms. 

There are a few reasons that SSRIs may lead to tighter waistbands:

  • Individuals with depression may gain weight because it is one of the symptoms of depression: eating more and moving around less.
  • On the other hand, some people eat less when they’re depressed and have unintended weight loss. If they take an SSRI and begin feeling better, their appetite may return, thus gaining back the lost weight.
  • Some theorize that SSRIs affect an individual’s metabolism or increase cravings, especially for carbohydrates and other heavy foods, but these theories have yet to be proved.
  • There is a link between obesity and depression. A systematic review and meta-analysis in 2010 found that obesity increases the risk of depression, but also that depression can be predictive of individuals developing obesity.

How common is SSRI weight gain?

There is conflicting evidence in research about SSRI use and weight gain. However, most studies agree that there is a risk of long-term weight gain with SSRI use. Here are some other relevant findings:

  • Within a timeframe of six to 36 months, 55% of patients on antidepressant therapy gained weight. Out of those who gained weight, 40% gained 7% or more of their initial weight. However, those on fluoxetine did not show significant weight gain. (General Hospital Psychiatry, 2015)
  • A survey of 700 patients taking SSRIs found that 38% of users experienced side effects. The most common were weight gain, sexual functioning issues, and drowsiness. Out of the patients dealing with side effects, only 25% said the side effects were very or extremely bothersome. (Psychiatry, 2009)
  • A follow-up study found that ​​4.6% of SSRI users had gained weight within a four-year time frame. (Diabetes Care, 2010)
  • A systematic review of all SSRIs found that Paroxetine was most likely to be associated with weight gain, while Bupropion and Nefazodone were the least likely to cause weight gain. (Journal of Clinical Psychiatry, 2000)

RELATED: Sexual side effects of SSRIs

Zoloft weight gain statistics

According to Forbes, Zoloft (sertraline) is the most commonly prescribed antidepressant, with over 38 million prescriptions written for it in 2017 alone. In fact, it’s in the top 20 of all medications prescribed in the United States. It’s approved for adults and children over six years of age. Along with treating depression, it is commonly prescribed for anxiety and other mental health disorders. 

  • A 24-week study showed that patients on sertraline (the generic form of Zoloft) between the ages of 6 and 17 years had a mean weight gain of 6.5 lbs, while those in the placebo group had a gain of 2.7 lbs. (JAMA Network, 2003)
  • Sertraline users gained an average of 5.9 lbs, compared to the reference group of fluoxetine users who gained 4.6 lbs in a two-year period. (Journal of Clinical Medicine, 2016)
  • Out of 281 pediatric patients, 2% reported negative adverse reactions, including decreased weight. However, weight gain was shown in children over a 34-week period. (Zoloft)

RELATED: Zoloft side effects

Prozac weight gain statistics

Prozac (fluoxetine) is used to treat depression, panic disorder, obsessive-compulsive disorder (OCD), and bulimia in adults. For children ages 10 to 19 years,  it may be prescribed for severe depression. 

  • A study in 1999 found that  fluoxetine users initially had a short-term weight decrease, an average of 0.4 kg, in the first four weeks. Continuation of fluoxetine for 50 weeks showed a weight gain of around 3 kg on average. However, this weight gain was similar to that of the placebo group. (American Journal of Psychiatry, 1999)
  • More recent studies have reported a slight amount of weight loss for fluoxetine users, around 1.3 kg total. (The Journal of Clinical Endocrinology and Metabolism, 2015) 
  • During the Food and Drug Administration (FDA) clinical trials, Prozac was found to lead to slight weight loss in some patients due to decreased appetite. (FDA)

RELATED: Prozac side effects

Paxil weight gain statistics

“Among the commonly prescribed SSRIs, the one that is most associated with weight gain is paroxetine (Paxil), though most other SSRIs are fairly close to paroxetine in terms of that association,” Dr. Culpepper reported. 

Paxil is only approved for adults because it has been associated with suicidal thoughts in adolescents and children. It’s commonly prescribed to treat depression, anxiety disorders, premenstrual dysphoric disorder (PMDD), and post-traumatic stress disorder (PTSD).

  • Patients taking paroxetine had a 25.5% increase in body weight compared to 6.8% for fluoxetine users and 4.2% for sertraline users. (Journal of Clinical Psychiatry, 2000)
  • A double-blind study lasting 24 weeks found that there was a higher risk of weight gain for patients taking paroxetine compared to those taking fluoxetine. (Journal of Psychopharmacology, 2000)
  • A more recent study found that paroxetine users had an average weight increase of 3.6%, compared to sertraline users with a 1% weight increase and fluoxetine users who lost 0.2% of their weight. (Psychopharmacology Bulletin, 2016)

RELATED: Paxil side effects

Lexapro weight gain statistics

Lexapro (escitalopram) is approved for adults and children 12 years of age and older. Escitalopram is FDA-approved to treat major depressive disorder and general anxiety disorder. Compared to other SSRIs, weight gain is not as common with Lexapro.

  • After six months of taking escitalopram, participants gained an average of 0.34 kg, increasing their body mass index (BMI) by 0.12. However, 7.6% of participants lost 2 kg or greater. (International Journal of Neuropsychopharmacology, 2011)
  • In FDA clinical trials, those taking Lexapro had no significant weight changes compared to those on the placebo. (FDA, 2017)

RELATED: Lexapro side effects

Celexa weight gain statistics

Celexa (citalopram) is an SSRI that is approved to treat major depression in adults. It has not been approved for use in children. There is limited research about the specific effects of citalopram and weight gain at this time. 

  • One study used citalopram as a reference compared to other antidepressants. There were three antidepressants that showed less weight gain than citalopram: nortriptyline hydrochloride, amitriptyline, and bupropion. (JAMA, 2014)

RELATED: Celexa side effects

Which antidepressants cause the most weight gain?

At this time, there has only been one study comparing weight gain in all types of antidepressants. This was a 10-year study using data from UK Clinical Practice Research Datalink, one of the largest electronic healthcare record systems. With this data, they were able to look at antidepressant use and an individual’s weight changes over time. 

Antidepressants with the highest risk of weight gain
Drug Name Drug Class Risk of weight gain compared to the placebo group (defined as 5% increase of body weight in one year)
Remeron (mirtazapine) Tetracyclic antidepressant (TeCA) 1.50 times higher
Celexa (citalopram) SSRI 1.26 times higher
Lexapro (escitalopram) SSRI 1.23 times higher
Cymbalta (duloxetine) Serotonin and norepinephrine reuptake inhibitor (SNRI) 1.23 times higher
Prozac (fluoxetine) SSRI 1.21 times higher
Zoloft (sertraline) SSRI 1.20 times higher
Desyrel (trazodone) SARI 1.19 times higher
Elavil (amitriptyline) Tricyclic antidepressant (TCA) 1.17 times higher
Effexor (venlafaxine) SNRI 1.15 times higher
Pamelor (nortriptyline) TCA 1.10 times higher

RELATED: What’s the best antidepressant for me? | SSRIs vs. SNRIs

How to manage antidepressant weight gain

“It’s important to note that fatigue, anxiety, and depression can also lead to overeating, and even binge-eating, in some instances – often worse at night. Following a healthy diet is often helpful, as well as limiting late-night eating,” recommended Alex Dimitriu, MD, double board-certified in Psychiatry and Sleep Medicine and founder of Menlo Park Psychiatry & Sleep Medicine and BrainfoodMD. 

Eating a healthy diet can help combat the pesky side effect of weight gain, but research also indicates that specific healthy diets can improve depression and anxiety. To learn more, check out the depression fighting diet or the anti-anxiety diet.

In addition to healthy eating, Dr. Dimitriu also said two other factors can help manage weight while taking antidepressants: exercise and sleep. While exercise burns calories and aids in weight loss, adequate sleep is also important. Dr. Dimitriu explained, “Sleep-deprived people are more impulsive (harder to resist the ice cream, or to stop eating when you’ve had too much), and their bodies also tend to seek out high energy, carb-heavy foods.” 

If you’re eating a healthy diet and getting physical activity each day, but your weight won’t budge, make an appointment with your prescribing healthcare provider. They may be able to switch the type of antidepressant you’re taking to something like Wellbutrin (Bupropion). According to Dr. Dimitriu, “Bupropion, also an antidepressant, but one which works on dopamine and norepinephrine instead of serotonin, is associated with the least weight gain, and even possible weight loss.“

SSRI weight gain questions and answers

Why do people gain weight on antidepressants?

The reason that people gain weight as a side effect of antidepressants is still unclear. It’s theorized that people become happier and eat more or that antidepressants change body chemistry in a way that increases appetite. 

Do antidepressants slow metabolism?

It is possible antidepressants slow metabolism, but most research indicates that this is not the case. It’s more likely that antidepressants increase appetite rather than slow down metabolism.

Does serotonin slow metabolism?

Serotonin does not slow metabolism. In fact, serotonin aids in reducing cravings and decreasing appetite. 

Which SSRIs will not cause weight gain?

According to the research by The Journal of Clinical Endocrinology and Metabolism, Prozac (fluoxetine) leads to a slight amount of weight loss. 

What causes more weight gain: Prozac or Zoloft?

Zoloft is associated with more weight gain when compared with Prozac. However, it’s not much of a difference. One two-year study by the Journal of Clinical Medicine found that sertraline (generic Zoloft) users gained an average of 5.9 lbs compared to fluoxetine (generic Prozac) users who gained 4.6 lbs. 

How do you lose weight on SSRIs?

The best way to lose weight on SSRIs is by eating a healthy diet and exercising regularly, as well as getting adequate sleep.

Will I lose weight after stopping antidepressants?

It is possible to lose weight once stopping antidepressants, but you’ll need to eat a healthy diet and exercise to have the best chance at weight loss. Never stop antidepressants before talking with your prescribing doctor. 

SSRI weight gain research