Does Zoloft Cause Weight Loss?

One of the most important things to do when considering medications for mental health is to understand all of their possible side effects. 

For example, the commonly used antidepressant Zoloft^® (the brand name for sertraline) is often associated with unintentional weight changes. 

There’s contradictory evidence on whether or not Zoloft is associated with weight loss or weight gain, but it seems more likely to result in weight gain. 

We’ve outlined how Zoloft works in your body, including how it may affect your weight and other potential side effects.

Antidepressants can work in a variety of ways to target certain aspects of your mental health, like trauma, anxiety, or depression. 

Zoloft is prescribed to treat a variety of mental health conditions, including:

• Major depressive disorder (MDD)

• Anxiety disorders, such as generalized anxiety disorder (GAD), social anxiety disorder, and panic disorder

• Obsessive-compulsive disorder (OCD)

• Post-traumatic stress disorder (PTSD)

• Premenstrual dysphoric disorder (PMDD)

Zoloft is a selective serotonin reuptake inhibitor (SSRI) that works by increasing the levels of serotonin, a neurotransmitter, in the brain. Serotonin is released from neurons (nerve cells in your brain that transmit information) and is known to influence mood, emotion, and sleep. 

Normally, serotonin is reabsorbed (reuptake) back into the neuron that released it after it has briefly interacted with serotonin receptors on the target neuron. However, Zoloft prevents this from happening, increasing the amount of serotonin available. 

This heightened serotonin brings about changes in the brain that help boost mood and reduce anxiety, which can help alleviate symptoms of depression, anxiety disorders, OCD, and PTSD over time. 

Note that SSRI antidepressants are similar but different from serotonin-norepinephrine reuptake inhibitors (SNRIs). SNRIs are a class of antidepressant medications that work by increasing the levels of serotonin and norepinephrine in your brain. 

Like SSRIs, SNRIs help to alleviate symptoms of depression, anxiety disorders, and certain chronic pain conditions by enhancing mood and emotional stability.

Like all prescription medications, Zoloft can have various side effects, including unintentional weight changes. While some people may experience weight gain, others may experience weight loss. It all depends on the individual.

While there are anecdotal reports, there’s limited scientific evidence of a direct causal link between taking Zoloft and weight changes. However, there is speculation of a long-term association.

Why Could Zoloft Cause Weight Changes?

When an SSRI boosts your serotonin levels, this may also affect other hormones in your body, including appetite-regulating ones like ghrelin (“the hunger hormone”) and leptin (“the satiety hormone”). 

It’s possible that people living with depression or anxiety may have higher levels of ghrelin and, consequently, an increased appetite. While SSRIs may help normalize ghrelin levels, they may not affect leptin as much. However, more research is needed on this suspected mechanism.

Chemical changes in the body are certainly a possible side effect of antidepressant drugs, but it’s also possible that some people simply lose weight due to changes in behavior associated with better mental health. 

Here are some of the potential mechanisms by which taking Zoloft could contribute to weight loss: 

• Appetite changes: Zoloft may affect appetite, leading to reduced food intake in some people. Also, some people with depression lose their appetite while others have a larger appetite or experience cravings for comfort food. As Zoloft normalizes the symptoms of depression, including appetite changes, the first group might gain weight while the second group could lose weight.

• Nausea: It’s not uncommon to experience nausea when starting Zoloft, which can decrease appetite and food cravings.

• Increased energy and activity levels: As depression or anxiety symptoms improve, you might become more active, potentially leading to weight loss.

The effect of Zoloft on weight can vary significantly from person to person. Some may experience weight loss, while others may not notice any change or may even gain weight. 

Factors such as diet, lifestyle, and how your body reacts to the medication play significant roles, so pay attention to anything that feels different and always speak with your healthcare provider if you’re concerned. 

What the Research Says

One study among animals found that sertraline inhibits extra body fat storage and alters carbohydrate metabolism in a species of monkeys. While this suggests an interesting explanation, results from animal studies can’t be directly applied to humans — so take it with a very large grain of salt. 

Human research on sertraline and weight change is lacking, but there are a few studies that suggest a potential association. 

First, one study among adults with type 2 diabetes and depression found that the addition of sertraline for 12 weeks resulted in significant weight loss, lower BMI, and an average reduction of waist circumference by 7 inches.

Another study on initiating second-generation antidepressants compared the weight-related effects of using various types of antidepressants, like fluoxetine (Prozac^®), citalopram (Celexa^®), mirtazapine (Remeron^®), and paroxetine (Paxil^®), finding that bupropion (Wellbutrin^®) was the only one associated with weight loss, and sertraline was associated with weight gain.

A study out of the UK also examined weight changes associated with antidepressant use. The authors found that weight gain was more likely. It also found that the greatest risk of a five percent (or more) weight increase is in the second and third years of treatment, all the way up to six years after starting treatment.

Finally, in a double-blind study among 284 patients with MDD, researchers randomly assigned them to receive treatment with fluoxetine (Prozac), sertraline (Zoloft), or paroxetine (Paxil) for 26 to 32 weeks. 

They found that paroxetine was related to the most weight gain, whereas sertraline was related to modest (but not significant) weight gain. Fluoxetine caused nonsignificant weight loss. 

Patients receiving paroxetine were more likely to experience a seven percent or more weight gain compared to those receiving fluoxetine or sertraline. 

Overall, weight gain appears more likely than weight loss when using sertraline for most people — but it’s not a guaranteed side effect. 

Strong research on this topic is limited because of the various factors involved in weight changes. 

Most studies comparing the weight change side effects of antidepressants have been unable to control for all of the variables among the samples, so more research is needed. 

The overall consensus appears to be that most antidepressants lead to only modest weight gain, if any at all, which can generally be addressed with a healthy diet and regular exercise.

Beyond the potential for weight changes, Zoloft can cause several other side effects. However, just like changes in your weight aren’t guaranteed, experiencing these additional side effects may or may not occur for you. Additionally, many of the side effects experienced early in treatment go away after a few days or weeks.

Some of the more common side effects of sertraline include: 

• Nausea

• Diarrhea

• Dry mouth

• Increased sweating

• Insomnia

• Decreased libido (sex drive)

• Difficulty achieving orgasm

• Dizziness

• Fatigue

• Drowsiness

• Either decreased or increased appetite

• Thoughts of suicide

In rare cases, some people may experience severe allergic reactions, seizures, bleeding and bruising, hallucinations, fever, sweating, confusion, agitation, and memory problems.

With any SSRI, it’s also possible to develop serotonin syndrome, a potentially life-threatening condition caused by an excess of serotonin in the brain. It can cause agitation, confusion, rapid heart rate, high blood pressure, dilated pupils, muscle rigidity, and, in severe cases, seizures and unconsciousness. Serotonin syndrome is most likely to occur when someone takes more than one medication that boosts serotonin. It’s rare with only a single SSRI.

If you experience any concerning side effects, it’s important to follow up with your healthcare provider for medical advice as soon as possible.If you’re experiencing more severe side effects, get emergency attention right away. 

Zoloft is an antidepressant medication that should be taken as prescribed and for what it is intended to treat. 

While it may be prescribed off-label (for reasons other than what it is FDA-approved for) for other mental health conditions, sertraline is not a drug that healthcare providers are prescribing for weight loss. 

Your antidepressant treatment plan should be tailored to issues affecting your quality of life. Period. 

If your weight is affecting your quality of life and your depression symptoms (and even if it isn’t), your healthcare provider will likely also suggest certain lifestyle changes, including: 

• More movement. Daily movement is good for your brain and your waistline. It also helps reduce your risk of obesity-related chronic diseases, like heart disease, diabetes, and cancers. Aim for at least 30-60 minutes of physical activity daily, including cardiovascular and strength training exercises. Choose things you enjoy, such as walking, playing tennis, biking, swimming, weightlifting, or dancing. 

• A healthy diet. Nutrition is a key aspect of long-term weight management and mental health. Boost the nutritional quality of your diet by focusing on foods like fruits, vegetables, legumes (beans, peas, and lentils), whole grains, nuts, seeds, and lean proteins, while minimizing ultra-processed foods that tend to be high in saturated fat, sodium, and added sugar but low in nutrients.

• Get better sleep. Adequate sleep helps regulate hormones that control hunger and appetite, such as leptin and ghrelin, reducing the likelihood of overeating. Additionally, we have more energy when we’re rested, making us more likely to be physically active. Aim for seven to nine hours of sleep per night.

• Psychotherapy. Cognitive behavioral therapy (CBT), for instance, is effective in helping people with mood disorders reorder their patterns of thought and ways of thinking for the better. Improving mental health can support long-term weight management and overall wellness.

If weight is a separate ongoing concern that isn’t being addressed by mental health care and lifestyle habits like diet and physical activity, you may also consider speaking with your provider about whether weight loss medications for obesity, such as weight loss injections and oral medications, are appropriate for you.

Hers offers anxiety and depression treatments and weight loss medications. 

Zoloft can be a highly effective antidepressant medication for treating anxiety, depression, and certain other mental health conditions. 

• It can have side effects. Like other drugs, sertraline comes with a slew of potential (but not guaranteed) side effects, which can include weight loss or weight gain for some people. 

• It’s not a weight loss drug. While some people may experience weight changes from using Zoloft, this isn’t a primary reason to use it, especially not in the short-term. Antidepressants cannot replace healthier lifestyle habits for long-term weight change, including physical activity, a healthy diet, and better sleep. 

• It may indirectly benefit your weight goals. Body weight changes and mental health are linked in many ways, and if you have depression, one may be dragging the other down. Getting your mental health under control can help boost your mood and make you more likely to crave exercise and make healthier food choices to achieve a healthy weight.

Whatever you’re struggling with, know that you’re not alone. 

Many people are facing similar mental health obstacles, and we’re here to help you through it. We know finding the right care person can be difficult, which is why the Hers online therapy platform is designed to offer you convenient and quick access to mental health support and wellness.

To get started, connect with one of our licensed healthcare providers by taking our free online assessment.