Does Zoloft (sertraline) cause weight gain?

Zoloft (sertraline) is an antidepressant that is used to treat depression and other mental health concerns. But while this medication can be an effective treatment for many mental health conditions, it can also cause side effects like nausea or a reduced sex drive. If you’re on Zoloft, you may also be noticing some changes in your body. 

For some people, Zoloft causes weight gain. For others, it causes weight loss. Read on as we explore the relationship between Zoloft and body weight, and offer tips for managing (or losing) weight while taking Zoloft.

Yes, Zoloft can cause weight gain for some people. One study found people taking Zoloft gained 10.5 pounds over two years, though different studies report different weight loss and weight gain results. The possibility of weight gain is not unique to Zoloft. Other antidepressants that may also cause weight gain include:

• Citalopram (Celexa)

• Escitalopram (Lexapro)

• Paroxetine (Paxil)

• Venlafaxine (Effexor)

• Duloxetine (Cymbalta) 

One of the common reasons Zoloft is prescribed is for depression. Of note, increased or decreased appetite can be a symptom of depression and is actually part of the diagnostic criteria for depression. Thus, it makes sense that people’s experiences with Zoloft can vary, especially when it comes to their weight. If Zoloft effectively treats people’s depression or other mental health issues, it might reverse the appetite change that people experienced in the first place. 

Some antidepressants, including mirtazapine (Remeron), are actually used as appetite stimulants and can help in people who are depressed and experiencing low appetite. Mirtazapine is thought to cause significantly more weight gain than Zoloft, which was confirmed in a large study conducted in the UK. On the other hand, some antidepressants — including bupropion (Wellbutrin), and even Zoloft can actually lead to weight loss. The amount of weight gain (or loss) you may experience while taking antidepressants can depend on a number of factors, from the dosage you are taking to whether or not you are a smoker. 

Researchers don’t yet know exactly why Zoloft and other depressants can cause weight gain for some people. There could be a number of factors at work.

Zoloft (sertraline) belongs to a class of medications known as selective serotonin reuptake inhibitors (SSRIs) which commonly treat mental health conditions like depression, anxiety disorder, obsessive-compulsive disorder (OCD), and post-traumatic stress disorder (PTSD). Serotonin is a neurotransmitter that plays a role in your mood, memory, sleep, and appetite, among other things. Normally, your brain uses serotonin to send messages related to these activities to different parts of your central nervous system. Once it sends the message, your body reabsorbs — or “reuptakes” — the remaining serotonin. SSRIs like Zoloft inhibit this reuptake process, so your serotonin levels increase and your mood can improve as a result.

Boosting serotonin levels can affect other hormones in your body, including appetite hormones like leptin (the satiety hormone) and ghrelin (the hunger hormone). More research is needed, but some studies have found that people with depression or any source of psychological stress can have higher ghrelin (hunger) levels. While treatment with SSRIs may bring their ghrelin levels back to a more normal range, it may not impact their leptin (satiety) levels - though studies addressing these topics have been very small.

As we mentioned before, there is no one-size-fits-all model to understand how antidepressants work in different people. If someone experiences loss of appetite as a symptom of their mental health condition and their antidepressant treats it, they may experience increased appetite and higher calorie intake.

Of note, studies of mice have found that while mice gain weight when placed under chronic stress and given a high-fat diet, they gain more weight when given antidepressants as well in the context of an already unhealthy lifestyle. 

Speaking of lifestyle, other factors can make you more likely to gain weight while taking SSRIs like Zoloft, including:

• Following a highly processed diet

• Living a sedentary lifestyle

• Smoking  

• Having a lower body mass index (BMI) at the start of SSRI treatment

• Having a family history of obesity

It is totally possible to maintain a healthy weight while on Zoloft. And, fortunately, many of the things that help you manage or lose weight are the very same things that can help alleviate symptoms of depression.

Eat well 

Improving your diet is essential to maintaining a healthy weight, or losing weight if that is your goal. Plus, following a healthy diet can also improve your mental health. 

While following a poor diet (e.g. lots of processed foods, refined carbohydrates, fried foods, sweets, soda) can increase the risk of depression, eating more mindfully can help relieve symptoms of depression — and may reduce the risk of recurrence as well. The following dietary habits, which are common in the Mediterranean diet, have been associated with a reduced risk of depression:

• Eating more fruits and vegetables

• Eating more fiber

• Eating fewer trans fats

• Eating fish

• Increasing your magnesium and folic acid intake

• Avoiding processed foods

Exercise more 

Regular physical activity is another important piece of the puzzle when it comes to managing your weight, whether or not you are taking Zoloft. And, research shows that the positive impacts of exercise on major depressive disorder are significant — enough to warrant healthcare providers commonly recommending exercise for those with depression.

Specifically, moderate to high-intensity aerobic exercise seems to have the strongest effects. Think running, jogging, biking, dancing, tennis, or hiking — anything that gets your heart pumping. But, ultimately, it’s about finding a workout that makes you feel a bit better afterward than you did before. Once you find that magic exercise routine, keep with it.

Sleep better 

Finally, make sure to get some rest. Sleep issues and depression seem to go hand in hand, with both insomnia and hypersomnia (sleeping too much) being common complaints of people with depression. It doesn’t help that insomnia can be a side effect of Zoloft and other antidepressants. If you’re experiencing sleep issues as a result of your antidepressant, talk to your healthcare provider about changing the time you take it to see if that can be an option.

Getting better sleep has been shown to lead to significantly more weight and fat loss, according to studies of people with overweight or obesity. 

So, do what you can to get at least 7–9 hours of sleep per night. Reserving your bedroom for sleep and sex, setting a sleep schedule, and avoiding naps can all help. Techniques like progressive muscle relaxation might help ease you into sleep. 

Yes, you can lose weight while on Zoloft. While this may be frustrating to hear for those who are experiencing unwanted weight gain, weight loss is a possible side effect of taking Zoloft and other antidepressants. 

In fact, people taking Zoloft are significantly more likely to experience decreased appetite — which can lead to weight loss — than those taking other SSRIs like escitalopram (Lexapro) or fluoxetine (Prozac). Decreased appetite is common enough to be listed as a potential side effect on the prescribing information for Zoloft, affecting about 7% of people in clinical trials (compared with just 2% of those taking a placebo).

Options for weight loss while taking Zoloft

If Zoloft is otherwise working for you, you can lose weight through the methods we mentioned above: improving your diet, exercising more, and getting better sleep. 

But, if you’re concerned about weight gain while on Zoloft, you could ask your healthcare provider about trying another type of antidepressant to see if your body responds differently. There are a number of antidepressant medications out there. While many SSRIs and tricyclic antidepressants cause a small amount of weight gain, some SSRIs, like escitalopram (Lexapro), and serotonin and norepinephrine reuptake inhibitors (SNRIs) are considered weight-neutral. And some antidepressants, like bupropion (Wellbutrin), are known to reduce appetite and food cravings to a large enough extent for some people to consider them anti-obesity drugs.

Furthermore, depending on your weight, you could be a good candidate for weight loss medication. Glucagon-like peptide-1 (GLP-1) medications like Wegovy and Zepbound can lead to significant weight loss. While the research is in its very earliest stages, there’s even a possibility that GLP-1 medications may help with mood, given their effects on serotonin and dopamine in the brain. However, it’s essential to take care of your mental health first before starting weight loss medications and any of these decisions should be carefully discussed with your healthcare providers to determine what treatment makes sense and is safe for you.

While they are not known to interact with Zoloft specifically, GLP-1 medications can slow down the digestive process, which may affect the absorption of any oral medications you are taking, including Zoloft. They are also contraindicated for people with certain health conditions, such as a personal or family history of thyroid cancer. Other weight loss medications, like phentermine, may also not be safe to take with SSRIs like Zoloft. 

Before starting any new medication, be sure to tell your healthcare provider about any over-the-counter and prescription medications you are taking, and fill them in on your personal and family medical history.

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Current version

March 26, 2024

Written by

Amelia Willson

Fact checked by

Raagini Yedidi, MD

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About the medical reviewer

Raagini Yedidi, MD

Raagini Yedidi, MD, is an internal medicine resident and medical reviewer for Ro.