Can Antidepressants Cause Weight Gain or Weight Loss?

SUMMARY

Changes in weight can occur during antidepressant treatment, but the relationship is not the same for everyone or every medication.

Research has found differences in average weight change between antidepressants, while other factors, including the underlying condition being treated, appetite, activity, other medications and duration of treatment, can also influence weight.

This blog looks at what current research tells us about antidepressants and weight, what may happen when treatment is stopped, and when to speak with a practitioner.

WHAT YOU'LL LEARN

• What research says about antidepressants and weight gain
• Whether antidepressants can be associated with weight loss
• Why different antidepressants can affect weight differently
• What factors can influence weight during treatment
• What may happen to weight after stopping an antidepressant
• What antidepressant withdrawal can feel like
• When to speak with a practitioner

Antidepressants are a group of prescription medications used to treat several mental health conditions. They include different classes of medications that act on different biological pathways.

Weight is one of the factors people may have questions about when starting treatment. Research suggests that some antidepressants are more strongly associated with weight gain than others, while some have a smaller association with weight change.

Importantly, an association between a medication and weight change does not necessarily mean the medication is the only cause.

Can antidepressants cause weight gain?

Yes, some antidepressants are associated with weight gain, but the effect varies between medications and individuals.

A 2024 target-trial emulation study published in Annals of Internal Medicine examined weight change among more than 183,000 adults starting one of eight commonly used first-line antidepressants. 

The researchers found differences in average weight change between medications over the first six months of treatment. Sertraline was used as the reference medication; several antidepressants were associated with slightly greater average weight gain, while bupropion was associated with slightly less. (PubMed)

A separate 2025 systematic review and network meta-analysis examined 151 studies involving more than 58,000 participants and found clinically meaningful differences in weight change between antidepressants compared with placebo. The analysis also found that the effects varied substantially between individual medications. (PubMed)

These studies are important because they show that it is too broad to say “antidepressants cause weight gain.” The effect depends partly on which medication is being studied, the length of treatment and the characteristics of the person taking it.

Can antidepressants cause weight loss?

Some people may lose weight while taking an antidepressant, particularly during earlier treatment, but weight loss is not a predictable effect of antidepressants.

Weight can be affected by changes in appetite, nausea, eating patterns, activity and the condition being treated. Clinical research also shows that antidepressants differ in their effects on body weight rather than producing one consistent pattern across the entire class. (PubMed)

For this reason, antidepressants should not be used or stopped for the purpose of losing weight.

Why can weight change during antidepressant treatment?

There isn't one explanation that applies to everyone. Several factors may contribute to a change in weight during treatment:

The specific antidepressant

Antidepressants don't all have the same effects on weight. Large comparative studies have found differences between individual medications. (PubMed)

Duration of treatment

Weight patterns can change over time. A short clinical trial may therefore show a different pattern from a study following people for several years.

Appetite and eating patterns

Changes in appetite can affect how much a person eats. Appetite can also change as symptoms of a mental health condition improve or worsen.

The underlying condition

Depression and other mental health conditions can themselves affect appetite, eating habits, activity and body weight. This makes it difficult to attribute every change in weight during treatment to the medication.

Other medications and health factors

Other prescription medications, health conditions, sleep, activity levels and changes in eating patterns can all contribute to weight changes.

In other words, a change in weight while taking an antidepressant doesn't automatically tell you what caused it.

Do all antidepressants affect weight in the same way?

No.

This is one of the clearest findings from comparative research.

The 2024 study of more than 183,000 people found measurable differences in weight change among commonly prescribed antidepressants during the first six months of treatment. (PubMed)

The 2025 systematic review and network meta-analysis reached a similar conclusion: antidepressants differ in their effects on weight and other metabolic measures. The researchers compared 30 antidepressants with placebo across 151 studies involving 58,534 participants. (PubMed)

However, these findings describe average changes across groups. They cannot predict exactly what will happen to one individual.

If weight is an important consideration when choosing treatment, a practitioner can consider it alongside your medical history, other medications and treatment needs.

Can you lose weight after stopping an antidepressant?

There is no predictable amount of weight that someone will lose after stopping an antidepressant.

If weight changes after treatment ends, there may be several possible explanations, including changes in appetite, activity, the underlying condition or other medications.

Research on antidepressant-associated weight change also does not support using discontinuation as a weight-management strategy.

If you're considering stopping an antidepressant because of weight changes, discuss this with your practitioner first.

What should you do if you're concerned about weight gain?

If you've noticed an unexpected change in your weight while taking an antidepressant, don't stop your medication on your own.

Instead, speak with your practitioner. They can consider:

• When the weight change began
• Which medication you're taking
• How long you've been taking it
• Changes in appetite or activity
• Other medications you're taking
• Other health factors that could affect your weight

Depending on your circumstances, your practitioner may recommend monitoring the change, reviewing other contributing factors or considering whether a different treatment approach is appropriate.

A pharmacist can also help you understand your prescription and discuss medication-related questions.

When should you speak with a practitioner?

Consider speaking with a practitioner if you experience:

• Significant or unexpected weight changes
• Persistent changes in appetite
• Side effects that are difficult to manage
• Concerns about continuing your medication
• Questions about reducing or stopping treatment

Your practitioner can help put the change in context rather than assuming that the medication is automatically responsible.‍

‍Frequently Asked Questions

Do antidepressants cause weight gain?

Some antidepressants are associated with weight gain, but the effect varies by medication and individual. Large studies have found differences in average weight change between commonly prescribed antidepressants.

Can antidepressants cause weight loss?

Some people may experience weight loss or changes in appetite during treatment. However, antidepressants are not weight-loss medications, and weight loss isn't a predictable effect.

Which antidepressants cause the most weight gain?

Antidepressants differ in their associations with weight change. Research has identified differences between individual medications, but population-level findings cannot predict how a particular person will respond. 

How much weight can you gain from antidepressants?

There is no single amount that applies to everyone. Weight change varies by medication, duration of treatment and individual factors.

Will I lose weight if I stop taking an antidepressant?

Not necessarily. There is no predictable pattern of weight loss after stopping an antidepressant.

What should I do if my antidepressant is affecting my weight?

Speak with your practitioner rather than stopping treatment yourself. They can review your medication and other factors that may be contributing to the change.

Are antidepressants used for weight loss?

No. Antidepressants are prescribed for their approved therapeutic uses, not as weight-loss medications.