Does sertraline (Zoloft®) cause weight gain? What the research says

Maybe your weight has shifted since you started taking sertraline (Zoloft®). Maybe your doctor just brought it up as an option, and weight gain is the part giving you pause. Either way, it’s a fair question, and a common one.

For most people, sertraline doesn’t cause a significant change in weight. 

Across the research, the average gain is a couple of pounds, spread over months or longer. Some people gain more. Plenty gain nothing at all. Among common antidepressants, sertraline (Zoloft) sits at the lower end.

The three studies below are where the modest-gain finding comes from, each tracking sertraline (Zoloft) users’ weight over different periods.

Study	Length	What it found
Fava et al., 2000	26 to 32 weeks	People on sertraline gained about 1% of their body weight on average, not a statistically meaningful amount. About 4% of people gained 7% or more of their body weight.
Maina et al., 2004	2.5 years	People on sertraline gained about 1.6% of their body weight on average, roughly 1 kilogram (about 2 pounds), one of the lowest amounts among the six medications studied.
Petimar et al., 2024	Up to 24 months	Used sertraline as the comparison point for seven other antidepressants rather than reporting a standalone number. See the comparison below.

What this chart means: Someone who weighs 150 pounds and gains 1 to 1.5% of their body weight puts on about 1.5 to 2.5 pounds over months to a couple of years. 

Your metabolism, activity level, and how depression or anxiety was already affecting appetite before your sertraline prescription all play a role, too.

Sertraline vs. other antidepressants for weight gain

Your doctor may have mentioned other antidepressants. In 2024, researchers compared seven of them against sertraline (Zoloft) in more than 183,000 adults.

Sertraline (Zoloft) is an SSRI, the most commonly prescribed group of antidepressants. The list below includes other SSRIs and a few from different groups.

Medication	Difference vs. sertraline at 6 months	Takeaway
Bupropion (Wellbutrin®)	About 0.2 kg (under half a pound) less, and the gap grew by 24 months	Less likely to cause weight gain
Fluoxetine (Prozac®)	About the same	No meaningful difference
Citalopram (Celexa®) and venlafaxine (Effexor®)	About 0.1 to 0.2 kg (a few ounces to under half a pound) more	Not enough to matter in practice
Duloxetine (Cymbalta®)	About 0.3 kg (roughly two-thirds of a pound) more; about 10% more likely to reach a 5%-or-more weight gain	Somewhat higher
Paroxetine (Paxil®)	About 0.4 kg (under a pound) more; about 14% more likely to reach 5%-or-more	Somewhat higher
Escitalopram (Lexapro®)	About 0.4 kg (under a pound) more; about 15% more likely to reach 5%-or-more	Somewhat higher

It’s OK if you’re worried about possible weight changes while taking sertraline (Zoloft). But before you think about making any changes, talk with your doctor about why you want to switch. They know how well your current medication is treating your symptoms and whether making a change is a good idea.

Can sertraline cause weight loss instead?

Weight gain isn’t the only pattern people notice on sertraline (Zoloft). Some people lose weight instead, and it’s just as normal: 

• In adults, decreased appetite is a recognized early side effect. It showed up in about 7% of people on sertraline versus about 2% on placebo, and it’s most common in the first weeks of treatment.
• In children and teens treated for depression, FDA trial data actually show more weight loss than gain: about 7% of children and about 2% of teens lost more than 7% of their body weight, compared with 0% and about 1% on placebo. Doctors typically monitor growth and weight more closely in younger patients for this reason.
• Both weight gain and loss tend to be most noticeable early on and level out with continued treatment. As depression or anxiety improves, appetite often shifts too, which can move weight up or down, independent of the medication itself.

If you gain or lose weight once starting sertraline (Zoloft), it doesn’t mean something is wrong. But it is worth mentioning to your doctor so they have a complete picture of how you’re doing.

Does weight gain get more likely over time?

It can, and that’s the main reason to keep an eye on this past the first few months.

People taking an antidepressant were about 21% more likely to gain 5% or more of their body weight over 10 years, and most of that difference showed up in years two and three. That finding covers antidepressants as a group, not sertraline (Zoloft) on its own.

Bring your weight up at a checkup a year or two in, the same way you’d bring up your sleep or your mood. A slow change over two years is easy to miss on your own, and easy to work with once your doctor knows about it.

The practical takeaway: Weight is worth keeping an eye on throughout treatment, not just in the first few months, and a checkup a year or two in is a reasonable time to bring it up if you haven’t already.

What to do if you notice a weight change on sertraline

Noticing the change is the useful part. From there, a few straightforward things help.

• Keep the basics steady. Regular activity, a consistent eating pattern, and enough sleep. Poor sleep and low activity can add to a medication-related change on their own.
• Write down what you’re seeing. Roughly when the change started and how much it has shifted gives your doctor something concrete to work from.
• Bring it to your doctor before adjusting anything. Depending on your situation, they might look at your dose, the time of day you take it, or, in some cases, a different antidepressant, weighed against how well your current one is treating your symptoms.
• This is a common conversation. Doctors have it often, and it’s a normal part of getting your treatment where you want it.

When to talk to your doctor

Reach out if a weight change is affecting your health, your confidence, or your day-to-day life, or if it’s accompanied by any new symptoms. Feeling like something’s off is enough on its own. 

A QuickMD online mental health care visit is the best way to start the conversation.

If you are having thoughts of suicide or self-harm, call or text the 988 Suicide and Crisis Lifeline, or chat at 988lifeline.org. In an emergency, call 911.