Does Prozac Cause Weight Gain? All You Need to Know

Published on: 22 May 2023
Clinically Reviewed by Bisma Anwar, LMHC
Does Prozac Cause Weight Gain

Does Prozac cause weight gain? It’s a question many people wonder about, and unfortunately, the answer isn’t always so straightforward. Prozac is an SSRI antidepressant used to treat depression, panic attacks, obsessive-compulsive disorder (OCD), and some eating disorders.  While it’s been touted for its efficacy, Prozac and weight gain is a concern for many. 

Here’s the deal. Prozac weight gain is possible. In fact, weight gain is a common side effect of many medications used to treat mental health conditions. That said, much research shows that, on average, weight gain on Prozac is actually less than what some people experience on other antidepressants, like Paxil (paroxetine). 

So, what are we to make of this conflicting evidence? Does Prozac really cause us to put on extra pounds or not? We’re exploring these questions and more as we try to understand if there’s any actual link between taking Prozac and gaining weight. Read on to learn more. 

Do You Always Gain Weight on Prozac?

Does Prozac make you gain weight all the time? It’s important to note that not everyone who takes Prozac will gain weight as a result. In fact, some people may even lose body weight while taking the medication. It depends on your body chemistry and how you respond to the drug.

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Even though Prozac can cause weight gain, it might help to know that this drug specifically isn’t believed to cause “serious” weight gain. Some research shows that, on average, people only gain about seven pounds when they start Prozac — and other studies show that slight weight loss is even possible.  

How much weight is gained on Prozac?

For most people taking medication, weight gain is an unwelcome and uncomfortable side effect. The amount of weight people gain when they take Prozac can vary from person to person. 

Some people see no weight change, some only see a slight increase in their body mass index (BMI), and others may experience more significant weight gain and changes in their overall size or shape.

“Moderate weight gain can certainly vary from person to person, but it’s not always a given with Prozac. Definitely work with your physician to understand what can be expected. As with all antidepressants, it’s important to know your baseline and maintain a healthy lifestyle to encourage optimal medication effectiveness. Always keep up with medication management appointments to note any changes as you navigate usage.”

Talkspace therapist Elizabeth Keohan, LCSW-C, LICSW, LCSW 

Why Does Prozac Cause Weight Gain?

Several factors can influence Prozac weight gain, including age, gender, lifestyle habits (like diet and exercise), other medications being taken at the same time or shortly after beginning treatment (e.g., antipsychotics), genetics, and individual body chemistry differences. 

There are several possible explanations as to why this side effect of Prozac may occur:

Increased appetite

Prozac and weight gain might be connected to increased appetite. People taking Prozac may feel hungrier than usual and crave certain foods more often. This could lead them to eat more calories than they usually would, resulting in gradual but steady weight gain over time.

Metabolism changes

Another reason someone might put on extra pounds while taking Prozac is that their metabolism can slow down due to hormonal changes. When your body doesn’t burn off calories as quickly as it used to, those extra calories can add up over time and contribute to unwanted weight gain.

Decrease in physical activity 

Even if someone isn’t eating more than usual, they might still gain weight on Prozac. This could be due to a decrease in physical activity levels resulting from fatigue, lack of motivation caused by the anxiety medication, or other conditions. 

How to Manage Weight Gain on Prozac

While it’s difficult to predict how much weight you might gain on Prozac, you still want to understand what you can do if you suddenly start gaining weight.

Monitor your weight

Keep track of your weight when taking Prozac. This will help you identify any potential changes in your body that might be related to the medication. You might want to weigh yourself once a week and record it in a journal or on an app so you can easily refer back to it.

Monitor your diet 

Eating healthy foods low in fat and sugar can help reduce calorie intake, leading to less overall weight gain over time. Additionally, avoiding processed foods and those high in sodium can help prevent water retention, which could further contribute to unwanted pounds.

Exercise regularly

Exercising regularly can help prevent weight gain while taking Prozac and improve overall health and well-being. Aim for 30 minutes of moderate exercise a day, such as walking, jogging, swimming, or cycling. If this isn’t possible due to time constraints or physical limitations, aim for 10 minutes, 3 times per day instead.

Watch your portion sizes

Overeating leads to weight gain regardless of whether you are taking Prozac or not. To avoid overeating, try using smaller plates when eating meals. This helps create an illusion that you’re eating more food than you actually are. Also, ensure that half your plate is full of vegetables or salad before adding other items like protein sources. This is an easy trick to ensure that portion sizes remain controlled at all times.

Get enough sleep

Getting enough restful sleep every night is critical in avoiding weight gain while taking Prozac. Aim for 7 – 9 hours of sleep each night. Regular naps during the day can also help maintain energy levels and better manage hunger pangs.

Talk to your doctor  

If you feel like you’re gaining too much weight too quickly, talk with your doctor to receive proper medical advice about possible alternatives, like switching medications or adjusting dosages.

“It can be discouraging to gain some weight while on Prozac, but a few tweaks can be positively impactful. Monitor stress routinely and take a look at your self care. Sometimes, noticing how stress impacts our daily nutrition, sleep, and relationships can be the key to taking some of the pressure off. Medication management is certainly a process, but over time, establishing a regimen that works well takes a little bit of time and patience to reach goals for diminished symptoms and increased coping. Enlist your clinician’s support to encourage an honest assessment about how to get the best results from medication and therapy combined.”

Talkspace therapist Elizabeth Keohan, LCSW-C, LICSW, LCSW 

Find Out If Prozac Is Right for You

Prozac is a popular psychiatrist prescribed medication used to treat depression, anxiety, and other mental health conditions. While Prozac can be an effective treatment for many people, it’s essential to understand how this drug works and if it’s right for you before starting a course of treatment.

Are you concerned about the potential of Prozac weight gain? Talkspace online psychiatry can provide you with access to qualified professionals who’ll help you understand your options and make an informed decision. With our customized approach, we ensure that all clients receive personalized care tailored to their individual needs. Don’t let fear or uncertainty hold you back from achieving a healthier life — take action now and get Prozac online if prescribed by a psychiatrist. 


  1. Fava M, Judge R, Hoog SL, Nilsson ME, Koke SC. Fluoxetine versus Sertraline and Paroxetine in major depressive disorder. The Journal of Clinical Psychiatry. 2000;61(11):863-867. doi:10.4088/jcp.v61n1109. Accessed February 9, 2023. 
  2. Michelson D, Amsterdam JD, Quitkin FM, et al. Changes in weight during a 1-year trial of Fluoxetine. American Journal of Psychiatry. 1999;156(8):1170-1176. doi:10.1176/ajp.156.8.1170. Accessed February 9, 2023. 
  3. Domecq JP, Prutsky G, Leppin A, et al. Drugs commonly associated with weight change: A systematic review and meta-analysis. The Journal of Clinical Endocrinology & Metabolism. 2015;100(2):363-370. doi:10.1210/jc.2014-3421. Accessed February 9, 2023. 

Talkspace articles are written by experienced mental health-wellness contributors; they are grounded in scientific research and evidence-based practices. Articles are extensively reviewed by our team of clinical experts (therapists and psychiatrists of various specialties) to ensure content is accurate and on par with current industry standards.

Our goal at Talkspace is to provide the most up-to-date, valuable, and objective information on mental health-related topics in order to help readers make informed decisions.

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