Remeron Weight Gain: Why It Happens and What People Report
Remeron (mirtazapine) is known for raising appetite, and weight gain is one of its most common side effects.
By withClaro Editorial · 2026-11-02 · 4 min read
Clinical section reviewed by Dr. Jason Tan , Consultant Psychiatrist, on October 27, 2026.
Key takeaways In the FDA trials, increased appetite affected 17% of people on Remeron against 2% on placebo. Weight gain was reported by 12% against 2% on placebo, and 7.5% gained at least 7% of their body weight; in a trial in children and teenagers, 49% did. Of 62 people on Reddit who said whether their weight changed on Remeron, 53 said they gained. Of 24 who gave a reason, 18 named a bigger appetite or cravings. On this page
How much weight do people gain on Remeron? Why does Remeron cause weight gain? What should you tell your prescriber about weight changes? Weight gain is one of the most common Remeron (mirtazapine) side effects, and it mostly comes through a bigger appetite: in the FDA trials, increased appetite affected 17% of people on Remeron against 2% on placebo. If you have had an eating disorder, tell your prescriber before starting, or as soon as you notice your appetite changing. Weight gain was reported as a side effect by 12%, against 2% on placebo, and a gain of 7% or more of body weight by 7.5%, against none. In an 8-week trial in children and teenagers, 49% gained at least 7%, against 5.7% on placebo, and Remeron is not approved for that age group.
How much weight do people gain on Remeron?
We read 73 recent threads where people discussed weight on mirtazapine, comments included, and 91 people described their own experience. Unlike the trials, nobody weighed them: these are their own accounts, and people with a change to report are more likely to post, so treat this as what a change looks like when it happens, not how often. Of the 91, 62 said whether their weight changed, and 53 of them said they gained. The 22 who gave a number typically gained about 28 pounds, and half gained between 14 and 36:
What people reported Of 62 people Gained weight 53 No change 7 Lost at first, then gained, or the other way round 2
Of the 53 who gained, 24 gave a reason, and 18 of them named a bigger appetite or cravings. One person on Reddit wrote:
I could never feel satisfied
Another person wrote that it didn't happen to them:
never gained weight on it
Why does Remeron cause weight gain? Medically reviewed by Dr. Jason Tan on October 27, 2026, this section only.
Mostly through appetite. A 2020 review in Obesity ties this to mirtazapine's action on histamine and serotonin pathways that control appetite, and a 2025 review places it with tricyclics and MAOIs among the antidepressants with the largest gains. The appetite effect shows early, already within the 6-week trials. In the label's pooled trials, including long-term open-label treatment, 8% of people stopped Remeron because of weight gain. The clinical view:
Weight can change on an antidepressant, and noticing a change early gives you the most options.
Several things feed into it: appetite returning as mood improves, cravings, less activity, poor sleep and the medication itself.
Your prescriber may adjust the dose or suggest a medication with a different profile. Stopping on your own to control weight can bring on withdrawal or a return of symptoms. ## Does the weight come off after stopping Remeron?
Few people said. Of the people on Reddit who gained, 8 had stopped Remeron and said what happened next: 7 said the weight came off and 1 that it did not. That is too few to say how often. One wrote:
Minute I came off it, within a few months I lost the weight
Any change to Remeron is a decision to make with your prescriber: the label recommends a gradual reduction rather than a sudden stop.
What should you tell your prescriber about weight changes?
Tell your prescriber what changed, when it started and how much it bothers you, and ask whether it is expected at your dose, when to check again and at what point a change of plan makes sense. A steady rise is easier to address while it is still small. It helps to tell them:
When you started Remeron, your dose and any dose changes. When you first noticed a change in appetite or weight. Whether cravings come at a particular time of day. Whether your clothes fit differently. Any history of diabetes or high cholesterol. More on side effects in Remeron side effects .
Download on the App Store Appetite on Remeron can change within weeks. The withClaro app lets you log appetite, energy, sleep and mood each day, linked to your dose, and turns it into a report for your prescriber.
Frequently asked questions Does everyone gain weight on Remeron? No. In the trials, weight gain was reported by 12%, and on Reddit 7 of 62 noticed no change. Tell your prescriber about any change.
Does a low dose of Remeron still cause weight gain? It can: on Reddit, one person who gained had been on 15 mg for a year. Tell your prescriber about appetite changes whatever your dose.
Is weight gain on Remeron linked to the sleepiness? Possibly in part. The label ties the sleepiness to histamine blocking, reviews tie the appetite to histamine pathways too, and feeling tired can mean moving less. Tell your prescriber about both.
Is Remeron used to help appetite? The label approves it for major depression in adults only, but prescribers sometimes use it off-label for sleep or poor appetite. Ask your prescriber what they expect it to do for you.
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Sources REMERON (mirtazapine) prescribing information, US Food and Drug Administration via DailyMed, revised November 2021 Gill et al., 2020, Obesity: Antidepressant medications and weight change, a narrative review Mouawad et al., 2025, Archives of Clinical and Biomedical Research: Impact of antidepressants on weight gain, underlying mechanisms and mitigation strategies Claro articles are for self-monitoring and educational purposes only. They are not a medical device, therapist, or diagnostic tool, and do not replace care from your prescribing clinician. If you are in crisis, contact your care team, emergency services, the Samaritans (UK: 116 123), or the Crisis Text Line (US: text HOME to 741741).