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Prozac and Weight Gain: Causes & Influential Factors

Prozac (Fluoxetine) is considered one of the most popular antidepressant medications of all time. It was developed by the pharmaceutical company Eli Lilly and approved for the treatment of major depression in 1987. Many people have had great success taking Prozac to manage depression, OCD, panic attacks, as well as eating disorders.

The drug functions as an SSRI (selective-serotonin reuptake inhibitor) which increases extracellular levels of the neurotransmitter serotonin. By increasing serotonin levels in the brain, many individuals find that it works great to help manage depression. Despite the fact that it can really help some people cope with psychiatric conditions, those taking it often complain of weight gain.

Prozac and Weight Gain

When people are prescribed an SSRI medication like Prozac, they are mostly focused on recovering from a mood disorder like depression – they aren’t concerned with potential side effects. In some cases a doctor won’t even inform patients of certain side effects with the thought that if a patient knows of side effects, they may discontinue a treatment that they need. In any event, many people end up noticing throughout the course of their Prozac treatment that they’ve packed on some extra pounds.

How Prozac Causes Weight Gain (Theories)

There are many theories as to how Prozac and other SSRI medications may cause weight gain. Some speculate that Prozac may slow the metabolism, while others believe that it increases craving for certain sugary foods like refined carbohydrates. Others may simply experience an appetite change while on the drug. In any regard, below is the laundry list of possibilities that may contribute to gaining weight on this medication.

  • Appetite changes: If you had a poor appetite before treatment, and all of a sudden you have a strong appetite after taking the drug, it’s obvious that you’re going to gain weight. Many people with depression don’t eat enough food while they’re depressed, and when they start treatment, their appetite returns and they start to eat. If you notice that your appetite changes, realize that this is a normal side effect from the drug.
  • Carbohydrate cravings: There is a relationship between serotonin and craving carbohydrates. Some believe that Prozac and other SSRI medications alter serotonin, which in turn causes some people to experience carbohydrate cravings. If you all of a sudden develop a sweet tooth and are eating more pastas while on this drug, it may be a result of this factor.
  • Drug interactions: It is important to consider that the drug may be interacting with another medication or drug that you are taking. The interaction between the two (or more) drugs may be causing you to gain weight. It is also important to consider the influence of the other drug on your weight before blaming Prozac.
  • Fat storage: Taking this medication may be increasing your body’s natural propensity to store fat. If your body starts packing on more fat than you were prior to taking the drug, it may be due to this particular factor.
  • Hormonal changes: Another idea is that Prozac creates hormonal changes in the body over the course of treatment. When hormone levels become altered, it can lead to increased hunger, fat storage, etc. Due to the fact that SSRI-induced hormonal changes has not been extensively studied, this is difficult to confirm.
  • Improved taste: Some have noticed that when they take a certain medication, foods taste significantly better. It could be argued that neurotransmitter alterations in the brain may also alter perception of taste. Those who now experience an improvement in taste are more likely to eat more frequently.
  • Less depressed: When people are less depressed from taking Prozac, they may be more likely to eat. When depressed, a person typically isolates themselves, eats less, and may not care about their personal health. Upon becoming less depressed, they may seek out food and better manage their hunger.
  • Motivational changes: Taking an antidepressant may result in a decrease in overall motivation. In other words, a person may feel so much better with their life, that they may see no need to exercise. This is a phenomenon that occurs in some people and could be called antidepressant-induced laziness. Those taking Prozac may become lazy as a result of the drug’s effects.
  • Side effects: The side effects of Prozac can include things like fatigue, tiredness, and grogginess. Not everyone will feel tired after taking the medication, but some people certainly do. Side effects like increased tiredness and decreased energy may lead a person to sleep longer and rest more instead of getting proper exercise.
  • Slow metabolism: Your metabolism may be the root cause of the entire Prozac-induced weight gain. Some speculate that regardless of whether you eat the same foods and portions during treatment as you did pre-treatment, you are still going to gain weight. This leads many to believe that the cause of this weight gain despite no change in foods or portions is a result of a slowed metabolism.
  • Social dining: Those who feel less depressed while taking an antidepressant often start to go out more often with friends. Engaging in social activities often results in “social eating” which generally isn’t healthy food. Social eating often results in going to fast-food restaurants and/or large portions of food.

Note: It is possible to experience a combined influence from many of the possibilities listed above.  In other words, a specific theory such as slow metabolism may not be the sole culprit for causing the weight gain.  It could be a compounding effect as a result of slowed metabolism, plus feeling lethargic, plus social dining.

Factors that influence weight gain on Prozac

It is important to recognize that there are other factors that will influence weight gain that a person experiences while taking Prozac. Most notably, the dosage, your lifestyle, how long you’ve taken the drug, as well as if you are on any other medications are often responsible for your weight gain.

1. Dosage

How much Prozac do you currently take? Those taking a high dose are significantly more likely to gain weight in comparison to those taking a low dose. When you take a higher dose, there is increased likelihood for side effects as well as physiological alterations. Essentially at higher doses, you are giving the drug more influence over your brain as well as body.

If you gained a little bit of weight at a low dose, but double the dose, you are also likely doubling the weight gain. This is why it is highly important to always stay on the minimal effective dose when taking this drug.

2. Individual factors

There are many individual factors that may play influence weight gain while on Prozac. These include things like: environmental stress, baseline metabolism, physiology, genetics, hormones, dietary intake, exercise habits, and your overall lifestyle. Many people assume that the drug is always responsible for the weight that they gain throughout treatment and fail to realize that it could be a variety of other factors as well. If you start craving carbs and end up eating a poor diet, this factor alone could be responsible for your weight gain.

3. Time span

The time span over which you have been taking Prozac also will influence the amount of weight you gain. Taking the drug over a short term period like several weeks often doesn’t give the effect of the drug enough time to “build up.” When you take the drug for moths, the drug will have elicited its effects on your brain and entire physiology.

If you stay on it for an even longer term, you may gain more weight due to the fact that it may alter your physiological functioning to a more significant extent. Additionally when many people take Prozac for a long term, they end up doubling the dosage due to tolerance at a lower dose. The increases in dosing along with long-term effects on your functioning make it easier to gain weight.

4. Other medications

Before assuming that the Prozac is directly responsible for your weight gain, also consider other medications that you’re taking. In some cases it may be the other medication wreaking havoc on your weight more than the Prozac. In other cases it may be that both your Prozac and other medication are each causing some reaction that leads to weight gain.

Yet in other individuals, both drugs could be working in synergy to compound the amount of weight that you gain. Always be sure to look up the potential side effects of other medications to determine whether they are weight-neutral or associated with weight gain.

How much weight will you gain from Prozac?

There’s no telling exactly how much weight you will gain from taking Prozac. Some people taking high dosages may gain quite a bit. Those who didn’t eat much prior to treatment who notice that their appetite increases may also gain a significant amount of weight. On average, most people that gain weight from Prozac and other SSRIs tend to gain 10 lbs. throughout the course of treatment. Fortunately, most people don’t view 10 lbs. as a significant amount and this negligible weight gain won’t bother them as long as the drug is working well for their depression.  Other uncontrolled studies have suggested it is possible to gain nearly 21 lbs. after 6-12 months of treatment.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/24898363
  • Source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC181155/

Will everyone gain weight while taking Prozac?

No. In fact, some people will actually lose weight for a variety of reasons while on this medication. Some people taking Prozac may actually lose interest in eating and/or become less hungry than usual. Others may not notice any weight change and for them the antidepressant will be considered “weight neutral.” It is estimated that nearly 1/4 people taking a particular SSRI drug like Prozac report weight gain. This means that for 75% of people, weight gain isn’t really much of a problem.

Prozac: Cost-Benefit Analysis

It is important to always conduct a “cost-benefit” analysis of any medication that you’re taking – including Prozac. If you gained a significant amount of weight, think about whether the drug is working well enough to justify this gain. For some individuals, the drug may not be working well and they may be gaining weight. In this case, a person may be better off going through Prozac withdrawal and/or switching to another medication.

Not everyone will have a great reaction to this drug, so finding a medication that you’re compatible with can be a challenge. If this medication causes you to gain some weight, but you feel significantly better than before you started taking it, it should be an easy decision to stay on it. Don’t let minor short term weight gain cloud your judgment into thinking that you’d function better without the drug if it has been working great.

Did you gain weight while taking Prozac?

Keep in mind that many people will gain no weight from taking this particular drug. For those that ended up gaining weight while taking Prozac, feel free to share how much weight you gained in the comments section below. It may help some to know the dosage that you were taking, how long you were taking it, and any other factors that you can think of that may have lead to an increase in weight. If you have any other thoughts regarding weight gain as a result of taking Prozac, be sure to mention them.

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{ 70 comments… add one }
  • E. Goyette April 11, 2015, 10:39 am

    I have been taking Prozac for 16 years. I started on 40 mg and eventually increased to 120 mg. I have gained 60lbs.

  • yvonne April 13, 2015, 6:32 pm

    Have had a great 4 years on Prozac but have gained 20lbs! Am now taking myself off it as am so down about my weight gain and my lack of control of it that I would rather go back to anxiety than this awful self hatred of my body that colors my every waking thought. Don’t really know whether my low mood and tearfulness, anger, and frustration is me withdrawing from Prozac or just being so fed up with not being able to wear the clothes I have and like.

    I’m at a loss to know what to buy for my new repulsive body. If I had realized that weight gain was a maybe side effect I would NEVER have gone on it. I was alright for the first year, then month by month a 1 lb. here 2 lbs. there. Calorie counting for months results in maybe a tenuous 2 lbs off. I belong to a gym and was doing 10 classes a week which helped, but now I can’t be bothered to go at all as nothing is working and I am too bloody tired.

    • DJ April 24, 2015, 3:51 pm

      I came up with a saying a long time ago that helps me out. “I am what I am until I am not!” This keeps me from getting deep into the self-loathing mind set. Whenever I would go into self-loathing, I’d get stuck, just like a car tire trying to get out of a muddy pit. The only results I got from self-hatred were not pretty and did not advance me one bit. I too have gained weight and am tapering off of the medication.

      My approach still has to be the same as stated above. Practicing patience with myself being as respectful to myself as I am to others in regards to self-talk are key to building yourself up on the inside. I know my friends would not put up with me if I treated them like I have treated myself at times in the past. We need to give ourselves a break and be our own best cheer leaders. I’ll cheer for you to Yvonne. We can build each other of on the inside as we whittle down on the outside.

  • Elaine May 19, 2015, 11:45 am

    I’ve been taking 20mg Fluoxetine for almost 2 years and I’ve gained 40 pounds. I will stop taking it as of today. I’d rather have anxiety than feel this crappy with the weight.

    • Margareta Bower June 2, 2015, 3:40 pm

      I too have been on Fluoxetine for over two years and have gained 28lb. Not good, as I am of slight build. It’s horrid. The cure here for depression is worse than the complaint! I am decreasing the dosage to one every three days – three more dosage to take, then doctor says that it will leave my system in a couple of weeks. Hope he’s right.

  • Derek June 9, 2015, 11:00 pm

    I gained 40lbs in about 12+ weeks on Prozac. I know it was because of all the junk food cravings I had, avoiding exercise, going out more and experiencing social eating. I wonder if I were to try the drug again, if I could counteract these effects…

  • Party June 16, 2015, 8:01 am

    I have now been on 20mg Prozac for almost 2 months I have noticed a horrific amount of sweet cravings I hardly ever’s crave sweets before I always would crave Veggies and fruit now I just want sugar, cookies, candy, and coffee drinks and McDonald’s. I’ve noticed my stomach getting fatter however my mind is not racing anymore and I feel more able to handle stress. However if I keep eating bad stuff and keep gaining weight, I may have to re-think…my family says I’m doing way better on Prozac and they see I’m happier and more active, I will stick with it for now, but if I don’t stop this crazy craving junk all the time I will have to stop!

  • DD July 13, 2015, 11:31 am

    I was on prozac 15 years ago and was always a healthy weight and exercised daily. On Prozac I found that I began to gain a lot of weight quickly and that did not stop even when I stopped taking the medication. I continues to exercise and only lost weight if I drastically cut out starches from my diet. And even after not taking the meds, my carb cravings are to the point that if I am stressed they are the cure. But I continued to gain weight over the last 15 years to the point where my clothes did not fit me from one season to the next.

    One doctor I went to tried to avoid giving me an answer but finally said, some people have a change in metabolism that does not go away even after stopping the pills. He said the only way to change it is to make me hypothyroid and “that’s unethical.”. But apparently it is ethical to make someone obese with all the health risks that accompany that. My thyroid tests year after year show normal thyroid numbers but my experience is as if I have a thyroid problem.

  • Pam W July 15, 2015, 2:41 am

    I was already overweight when I started taking Prozac. I’ve been on it for about 8 years and am now morbidly obese, a gain of 60+ pounds. I have tried low fat, low carb, low calorie, walking, swimming, weight lifting. No matter what I have tried, the results are disappointing and impossible to sustain. Today is the first time I have had this information about Prozac and weight gain; it’s a real eye opener. I was planning a doctor visit tomorrow to discuss weight loss surgery, but now I believe we will be talking about how best to wean myself off this medication while giving another shot at the low carb eating plan.

    • Lucy July 16, 2016, 1:40 pm

      I am so glad I found this website. I’ve been on Prozac for 3 years and have gained 80 pounds. I will take partial blame but like others have mentioned I crave sweets and feel tired all the time. I’ve tried dieting and exercising and I haven’t been able to make a dent. It really perplexed me as I was walking and eating salads. I even GAINED weight dieting. I’m going to gradually stop this prescription and see what happens.

      • debbie October 19, 2016, 5:26 pm

        I have been going thru the same thing. I am so glad I saw this… I even printed some of the comments and took them home and read them last night. I quit smoking Jan 4th of this year and the day I quit, I went on a diet too. (with no luck at all-didn’t lose 1lb). So then I decided in April to go to The Doctor’s Diet Program, you go once a month and they give you phentermine pills and they teach you what foods to eat and what foods to stay away from.

        Since April I have lost a total of 2-lbs. Exercising minimal, I do walk in the evenings if it is not too hot. I mean I cut out potatoes, bread, sweets. I feel like I should have lost 40-50 lbs because I have been eating so well… but NO. I started weaning myself off of the Prozac this morning, I had been taking 60mg a day.

        It did help my anxiety and depression but I have been so “engulfed” in all this weight and trying to get it off, I think I would be better off just coping with it and focus getting this weight off. I have said it numerous times and think it over and over… I will get this weight off or I will die trying!!! I am sooooooo happy that I saw everyone’s comments on their experience with Prozac.

  • Maria K August 4, 2015, 1:42 pm

    I am an all natural/organic eater. Nothing processed, an occasional treat kind of person. I go to the gym 6 days a week, switch it up between cardio, core and strength. 5 months ago (around that time) I saw my gyn because I am going through some serious permenopause symptoms. Low libido, tired, short term memory loss, major hot flashes during the day and awful night sweats at night but most of all my anxiety was through the roof, I couldn’t calm down for anything.

    That was the worst of everything. My doctor prescribed me 20 mg of prozac (fluoxetine) and I mean, the anxiety is all gone, I have to say it has really helped with my anxiety however I have gained (during the last 5 months) 32 pounds and this is with me still eating naturally and working out 6 days a week!!! Could you imagine if I had stopped doing that and gave in to my cravings???? I am only 5’0″ and I weigh 178 pounds.

    I can’t fit in any of my clothes, I constantly feel full to the point where I am so uncomfortable. I am not certain if it is from the prozac or if I have another underlying condition? It is so crazy for me but I can say that I can’t do this anymore and I am not sure what to do, I am afraid to ween of the prozac because I don’t want to experience that anxiety again but physically I feel so crappy.

    Today was my cardio day, did the treadmill for 50 minutes at a random incline, burned almost 600 calories and I am tired when I used to feel exhilarated.

    • K.l.nikolov October 4, 2015, 10:21 pm

      I’ve had the same problem. I practically eat the same things every day: Lemon water (homemade), 2 tbsp yogurt with tsp honey and pureed fruit. Water and some kind of fruit as a snack. Fish or chicken salad with rice. Soup (homemade). I drink at least 2 ltrs of water a day, if not more. I rarely have sugar etc.

      I have a very active lifestyle. For so long I thought it was that I was being inactive – my body had got used to it and I needed to do more. But no. It is this medication. I’ve been on and off meds for YEARS and I can tell you Prozac and Risperdal are the WORST for weight gain. When I was 14 I literally put on 5 stone in 8 weeks and it took me 8 months to shift after my parents put up a battle for me to stop the medication. Don’t be fobbed off with excuses.

      Typically if you have made no changes to dietary or eating habits but are on SSRI medication the weight gain can be traced back to that. Initially you will lose weight on them. Rule of thumb I follow is the length of time you have been on the medication triple it and that is how long it will take for you to lose the weight you have gained ONCE the medication is out your system.

      Honestly, I think weight gain causes more issues with anxiety and depression/ other issues than the actual basic concern. Talk to your doctor and try not to over work yourself to make yourself stabilize your weight – there are other medications etc.

  • Jewey August 17, 2015, 2:45 pm

    I was thin my whole life until prozac. Then, not only did I gain weight, I developed cushing syndrome. I stopped taking it about a month ago and have already noticed a huge difference in my weight and how I feel. So glad I figured it out that the Prozac was causing this!

  • Carol September 5, 2015, 2:01 am

    I have been taking prozac on off for about 10 years and I just realized that I am the largest I have ever been in my life. I steadily keep gaining more weight as the years go by. After reading everyone’s comments I realized that when I was off the medication I lost weight. I too have began to really dislike my body and the way I look. Nothing I do as far as dieting and exercise seem to help. I believe I’d rather live with the anxiety than feel horrible about myself. As of today, I will start weaning myself off prozac.

  • Diane September 19, 2015, 8:30 am

    I have been on Prozac since for about 10 weeks in that time I have gained almost 35lb, I don’t feel any motivation to do anything, and the Dr has upped my dose to 40mg, of which I have now been taking for the last two weeks. I can’t feel full no matter what I eat. My sugar cravings are through the roof and I am disgusted at what I can eat and what I give in to. I am going back to the Drs on Monday see if she can give me anything else instead because I can’t carry on like this, it’s making me even more miserable.

  • Tina September 26, 2015, 6:13 am

    I lost 25lbs on prozac! In 5 months! I just stopped taking it and am gaining weight. I think everyone is different.

    • jeng April 2, 2016, 9:11 pm

      My depression lead to a 30lb weight loss. Went on Prozac and started eating again. I didn’t start gaining weight until going OFF prozac. I have been off for 5 months and gained 40lbs. I have really never struggled with my weight so this is a bit disconcerting for me. I am athletic and don’t eat that much garbage food.

  • kim September 29, 2015, 4:20 pm

    I am currently taking 40mg, I was at 20mg. I changed about 2 months ago and I work out regularly and cant lose a pound. When I was taking 20 I had been going to gym as well and lost 10 lbs in 4 and 1/2 weeks. I actually work out more and harder now and cant lose anything. I am thinking it has to do with the dosage change. I have decided to go back down to 20mg and see what happens. I work out hard and count calories and not looking to gain weight.

  • melissa hunt October 5, 2015, 6:55 pm

    I also have been on FLUOXETINE (Prozac) 40mg for almost a year now. I started at 20mg for about 6 months. I never ever ever have an appetite at all except for strawberry licorice. I have been freaking because all of a sudden I cannot fit any of my clothes! I am going on a cruise soon so I am going to stop taking my meds. The weight gain is making me feel more depressed now than I was before I started taking prozac! I was 123lbs when I started now I am all of a sudden like over night 142!!

  • wrd October 8, 2015, 1:02 pm

    Sorry to hear that people have been gaining weight. This is happening to my teenage daughter who’s on Prozac. I plan on taking her off it and trying psychostimulants instead. Personally, I believe that SSRI/SNRIs are a scam perpetrated by Big Pharma. Remember, only about 30% of people respond to them. That leaves the majority being medicated for no reason, some with major side effects, plus it takes several weeks for each medication to have any effect.

    There you are wasting months or years of your life! Read up on dopamine deficiency on this site and you’ll see that it can be the cause of depression and low libido. You don’t have to have ADHD to be prescribed it. I’ve been depressed for at least 10 years, tried different SSRI/SNRIs, tricyclics, benzos, ketamine infusions, medical marijuana and nothing worked until my latest psychiatrist diagnosed me with dysthymia and prescribed, first, Adderall, then Dexedrine when the Adderall was making me jittery and irritable.

    The Dexedrine was the first time any medication really worked. It makes you alert, lifts the depression, brings back the libido, and decreases your appetite so you can lose weight. And the great thing about psychostimulants is that it takes effect immediately so you’re not wasting your time over many weeks. Obviously, the downside can be that some people will abuse the drug, some won’t respond or it makes things worse, and you might have to try different psychostimulants to find the one that works for you.

    But the good news is that you can quickly go through all of them in short order, 1 month. Are they miracle drugs? No, but if you’ve been struggling for years, then, yes, it would be miraculous to you. I would suggest Dexedrine first as it’s smoother than Adderall, the 25% levo it has can cause problems. I can understand why doctors are prescribing SSRIs first as they are “safer” but I think they are doing people no favors by only focusing on serotonin and ignoring NE and dopamine.

  • mad November 1, 2015, 11:22 pm

    Went from size 6 to size 12 in only 6 months :(

  • sandra willis November 24, 2015, 11:03 pm

    I was on this drug for a long time and I gained thirty pounds. It was too late when I realized what had happened. I have not lost the weight no matter what I do. I will not take it again.

  • Wendy November 26, 2015, 1:54 am

    My son (age 7) put on 15 lbs in the first 8 months! That’s a huge amount for for a child that started taking it at 50lbs…

  • Shauna November 26, 2015, 7:38 am

    I take 80mg a day of prozac and I’m going to start slowly reducing my amount due to the weight gain and overall fatigue I feel everyday. I still have terrible depression regardless of the medication, so it hasn’t helped me at all.

  • Melanie Greaves December 30, 2015, 7:40 am

    I took 20/40mg for nearly 9 years and I put on nearly 2 stone. But the most distressing thing for me was even though I did lots of exercise, and was very careful with my calorie intake, I just could not lose the weight!

  • Echuard January 13, 2016, 2:11 pm

    I am skinny and a hard gainer, I’ll be starting prozac from tomorrow and hope to gain weight, whoop whoop!

    • Jackie March 23, 2016, 9:07 pm

      I thought it would be nice to gain a little weight, but in 2 months I have gained 10 pounds. I can’t stop eating, I am always hungry. I wanted to gain weight but it does not go where you want it to, all in the stomach.

  • Stephanie January 21, 2016, 7:05 am

    I always read that Prozac wasn’t one of the ones that would put on the weight. But after all that I have read and being on it for 2 years straight… I now believe it.

  • Bree January 21, 2016, 9:38 pm

    I am sorry to hear so many terrible experiences with weight gain from Prozac. I took the generic form Fluoxetine for my OCD and it helped tremendously. I am not sure if it matters if it was the name brand that makes the weight gain difference. I started taking it in September 2009 and I can’t remember the exact amount I started out on but stopped taking it in 2013 with 80mg.

    I DID NOT GAIN ANY WEIGHT… I talked to my doctor about getting off of it since I did not want to be on drugs the rest of my life and I felt 95% cured. I just stopped cold turkey with no withdrawal symptoms. In fact I had been off the drug for about a year and a half and started noticing signs that the OCD was gradually getting worse. I actually asked my doctor to be place back on the drug but I guess from being off for a while it did not work the same.

    I felt really depressed and sad after 2 weeks of being on it. I just decided on my own to stop taking it… Please do not be afraid to try this drug. It worked for me for a long time and everyone handles drugs differently. I should have never stopped taking it and should of maybe just gone down in dosage. As of yesterday my doctor prescribed Celexa 40mg. I heard horrible stories about the weight gain with this drug, but I think I am going to give it a try… Fingers crossed :).

  • Amanda January 25, 2016, 3:08 am

    Just started taking Prozac 3 days ago and have been trying to find the most amount of information about it that I can. I did NOT know this many people are gaining weight! I’ve been dieting these last few weeks when I found out I was going on a cruise in a few months, and I already don’t have the bikini body that I want so now I’m super worried!

    Does anyone have a diet or exercise plan that has helped them loose weight while on Prozac? It would be extremely helpful to know! Or even some tips they use for stopping the cravings? Please help! I think I’ll be getting engaged on this cruise and I want to be excited and not depressed, but I also want to look and feel good! Thanks everyone!

    • Linda October 1, 2016, 10:14 pm

      I took Prozac for about 15 years and switched to fluoxetine about 5 or 6 years ago. My weight has been gradual. I am about 35-40 pounds overweight now. The doctor said I would need to take it for the rest of my life. When I started taking fluoxetine I started noticing more weight gain. I cut way down on my eating (was not a big eater anyway). No matter what I do I do not lose one ounce! I never even thought it was the medicine until I found this site. I am going to gradually take myself off of it. So, exercise and eating do not seem to help. I’m now depressed because I am so FAT!

  • un known February 9, 2016, 3:06 pm

    I have gained 20 pounds since the first dose and I can’t seem to keep it off. Any suggestions on how to contain it?

  • Melissa February 23, 2016, 4:21 pm

    I started taking 20 mg of Fluoxetine a day in 2014. I have put on 15 pounds and cannot get it off. I’ll keep trying though!

  • Kelly February 24, 2016, 4:31 am

    OMG. I’m so happy I just stumbled across this thread- I could cry! It started ever so slightly…I noticed the scale numbers gradually going up and every few months my clothes would stop fitting and I had to replace them with the next size up. I started getting so mad and disgusted at myself (especially when I saw pictures of myself).

    Even my friends and coworkers noticed it too… how embarrassing. After two years, I went from 127 lbs to 150 lbs, from a size 2 to a size 8/10 and I’m only 5’4″. I DON’T eat a lot and I’m very active- I run, hike and rock climb!!! Today I almost broke down. My weight keeps increasing with no end in sight:( I Googled “unexplained weight gain” and many sites pointed to hormone imbalance and/or antidepressants.

    I didn’t think this applied to me since I’ve been on antidepressants since 18 (I’m 30 now). Then I remembered, EXACTLY two years ago my doctor switched me to Prozac!! Reading all of your posts made me cry because finally I know what’s wrong and I don’t feel like a big fat disgusting failure anymore. I thought I was doing this to myself!! I’m stopping this BS tomorrow.

    I don’t care that it’s been working well, I firmly believe there are other alternatives to curing my depression than one that involves sending me on the road to obesity!! Good luck everyone – I hope you lose it all and thanks for the support. :)

    • Tracy August 13, 2016, 7:55 am

      Like you, I’ve been on it 2 years. About 9 months ago, I started taking Rexulti too, and I’ve gained 21 pounds. I’m 5’6, and I’ve always been 135-140, a size 8. I just bought a tight size 12! They say after time you can gain more. Lovely!

  • stephanie February 25, 2016, 3:11 pm

    I went from a steady 130 to 170 over a course of taking Prozac for two years. I’m not eating different or exercising less. Yes I feel better mentally but I wish I didn’t gain so much. :(

    • Tracy August 13, 2016, 7:56 am

      Ditto. Very upsetting.

  • Flood March 4, 2016, 5:57 am

    I gained 15 pounds in 3 months. I also had horrible nightmares. Not worth it for me. Exercise and low carb diet works better.

  • Sharon March 4, 2016, 12:03 pm

    I have been taking Prozac for about a year. Started on 20 mg but after 6 months it was increased to 40 mg as it seemed ineffective. I have gained 7 lbs since increasing the dose 6 months ago. I am active, an avid gym goer and I have a very physically active job. I have not changed my eating habits except to watch more carefully my intake.

    I am still gaining weight and I am so frustrated. I am 5’1″ and can not hold a lot of weight. I really like the calmness and lack of anxiety but I feel that I am more negatively effected by the weight gain that does not seem to be stopping. I am ready to find a more natural solution to Prozac.

  • Michele March 9, 2016, 9:11 am

    Over a period of one year I gained 20 lbs…became less motivated and craved foods I’d never eaten before. I suggest if you have BDD then do not use this medication. It will cause weight gain.

  • Lea March 16, 2016, 8:18 pm

    I’ve been on 20 mg of Prozac for about 12 years. In the last 5 years I’ve been steadily gaining weight. No amount of exercise/dieting has much, if any, impact. I was always a normal weight for my height, 5’5″ averaged 120-125 pounds, ate healthy and worked out 4-5 days a week. I still eat healthy and work out 5 days a week and I’m now almost 140 pounds and feel so depressed! I look about 4 months pregnant most of the time. I hate how fat I feel, I’m slowly weaning myself off Prozac and praying this helps and that I can get this extra weight off for good.

  • Kate March 29, 2016, 5:59 pm

    I went from a easily maintained 115lbs to my heaviest weight of 160lbs while taking this drug. I gained the weight in a matter of months. I did not change how much I worked out and continued eating food I normally ate. It has been years since I have been off the medication and I am only half way back to what I use to be. The medication also made me numb and unable to feel anything. Definitely not worth the years of body image issues which only made me more depressed and a much slower metabolism.

  • Tammy April 3, 2016, 8:34 pm

    My teenager has been using generic prozac for about 2 years. She’s gone from 20mg to 40 to 60 and back to 40mg now. Dr said there may be a slight weight gain but nothing to worry about. I’d say 30 plus lbs is something to worry about. She’s had anxiety issues. She has gone from 117 to 151 lbs. She doesn’t eat any different than before. She now has body issues and doesn’t feel like doing anything. I’m so worried about her but don’t know what to do.

  • Karen Carr April 5, 2016, 5:50 am

    I too am gaining weight on prozac. Went from 20 to 40 to 60mg. Crave sweets bad, always hungry. I am putting myself back to 20mg and then try to get off of it and on something else. Been on meds since 2001, seems like I just started gaining in last 2 years or so. Was on prozac before and did not gain, but in the last 2 years I am gaining now. Strange.

    I am 58 and have thyroid issues so since depression can be from thyroid issue too I want to see if I can slowly get off prozac and let thyroid med do its thing. Maybe I am not even depressed, but it is thyroid issues. When off prozac maybe I will get back to normal, I pray anyway! Gaining weight is very depressing!

  • Maria April 7, 2016, 10:34 am

    I’m so glad I came across this thread as I too could not understand why my weight increased by almost 14lbs over the last 5 years. I took 20-40mg Fluoxetine for the last 5 years and stopped taking it two weeks ago. Has anyone, who has stopped taking fluoxetine, lost the excess weight and how long did it take you to go back your usual weight/size?

    • barb May 27, 2016, 5:37 pm

      Hello Maria, you can not just stop taking prozac, you have to wean off. A little less every other week. I am doing it that way, have not lost any weight yet. But I will keep you informed if I loose any weight. By the way, I started taking St. John’s wort capsules. They are great to help with improving mood swings and help you to stay calm. All natural, no side effects.

  • Geneva April 8, 2016, 8:05 pm

    I can’t stand this drug – it’s horrid and I have went from 130lbs to 160lb. I have been on it for about two years. First I was taking 40mg so I asked home to decrease it to 30mg but that didn’t work so I took myself down to 20mg!!

    Today I went to the doctor to see if he would change me to something else because of the weight gain — but he said “Prozac don’t make you gain weight” so he dropped my dose down to 10mg but I’m thinking about going to another MD because the weight gain is horrid.

  • Celia April 19, 2016, 9:28 pm

    I’ve been taking it (on and off) since 2007. In the last four years I’ve gained at least 35 pounds. I didn’t know that you could gain weight while taking Prozac, I was always under the impression that it was supposed to cause the complete opposite. Lately, I’ve been experiencing impossible cravings. I read that my antiallergic medication could be responsible and now the Prozac! I’m going to consult with my doctor.

  • barb May 22, 2016, 8:04 pm

    I have been on prozac for 10 years and I gained well over 20 pounds. I hate it. Now I am trying to wean myself of off prozac in hope to lose the weight again. I am going to try all natural remedies for panic attacks.

  • Katherine May 26, 2016, 10:17 pm

    I have been on at least 20mg of prozac for severe OCD since the age of 8. My dosage has gradually increased over the years, and I have been on 60mg a day for 1.5 years. I have never been even close overweight, nor have I had any notable spikes in my weight. I am currently 18 and have an 18 BMI, and require very little effort to maintain my weight.

  • Cindy May 28, 2016, 10:57 pm

    I took the generic form of Prozac, Fluoxetine and over the last 6 months have gained 30 lbs. I am so upset! I am 5’2 at 115 lbs normally so the nice 145 lbs at my height is tearing me up. I started on 20 and went up to 30. I am going off of it as my major crisis is now behind me starting with going back to 20 and then down to 10 and off. Now that the weather is getting warm it feels horrible to be hiding my weight under larger clothes such as sweatshirts and pants. :( Hope I can get myself back within a couple months.

    • Linda October 1, 2016, 10:23 pm

      Good luck. I am 5’1″. I went from a 115 to 150. I am more depressed now because of my weight gain. I am just going to gradually get myself off it. It is so good to know it is probably my medication, now I don’t feel so much like a failure.

  • Marianne June 1, 2016, 3:35 pm

    I’ve been on and off Prozac for years. I’m a 30 year old woman, 5’8. Started off as naturally thin, about 130-135 pounds. Now I’m at least 150 after taking Prozac. I do want to stress that it did make me feel better mentally/emotionally, so I’m sure I eat more now than I used to. I’m a “non eater” when I get depressed/anxious, and I had both depression and anxiety when starting the drug.

    Now, I understand I’m not overweight for my height. But for ME, I’m not used to this. Hubby is happy, says I look better than ever, but for me, I personally do not like it. Despite friends and relatives all telling me how much better I look with “meat on my bones,” I just don’t agree. I’m very active, both running and riding my horses frequently.

    Tried to go off it cold turkey. I had zero physical side effects, but I did end up with mental and emotional side effects after a few weeks. I’m talking outbursts of anger, sadness, fear, worry, etc. So now, I’m back on it. I hate being this size (used to be a 6, now I’m a 10), but without it, I feel awful after a while.

    I fear for my future. We want to have a family eventually, and I can’t do that while being on this drug. It worked wonders for the problems I had, which are mostly caused by situations in my life, but the side effects are just as depressing.

    • Jenni August 11, 2016, 3:50 am

      Marianne: I had the same reaction when I went off. I am so scared it’s going to happen again. Stay strong!

      • Melissa September 27, 2016, 4:31 pm

        You can’t stop taking it cold turkey – that is very dangerous. Talk to your doctor about weaning yourself off… They will work with you to gradually reduce your dosage – 40 to 20 to 10 mg or whatever. PS – if it makes you feel any better I am about the same size/weight as you but I am only 5’3″! :(

  • Shirley June 13, 2016, 11:41 pm

    I have been on Prozac for 13 years. I started at 20mg progressed to 40mg after 5 years and now have been increased to 60mg. After 1 week of 60mg I have gained 10 lbs. I’m now at 273 lbs. I’m 5’4″. I too have become disgusted with my size and tried every diet out there only to gain weight, not lose it!

    I think I too am going to wean myself off Prozac. I am not real active because of other health issues, but being anxious or a little depressed is better than not being able to find a chair that will hold my weight or hear my grandchildren tell me I’m too fat. We shall see.

  • Pigeon July 2, 2016, 7:25 am

    I remember taking 20mg of Prozac about 4 years ago for a few months and gained at least 22 lbs!! About a year later I felt bad and decided to lose the weight again. But then I went on it again two months ago and a month after that I noticed I started at least gaining at least 7-10 pounds in the first month and am afraid the same thing might happen again. Best thing for me is to not take Prozac – ever! Even if it doesn’t increase my appetite!!

  • Belinda Ramos July 7, 2016, 1:14 am

    I’ve been on Prozac for about 3 years now and I have gained over 85 pounds! My psychiatrist FINALLY decided to let me know that my weight gain was caused by Prozac only just recently, and I am SO FREAKIN MAD!! I have had weight issues my whole life and my psychiatrist knows this, and she still put me on this bullsh#t drug!! How is more weight gain supposed to help my depression? I should sue her or something!!

  • Jordan July 18, 2016, 7:09 pm

    I had been on 20mg prozac for almost 2 years and I’ve gained about 30 pounds that I simply cannot lose. I went down to 10 mg about 2 weeks ago, but still no change. I’ve reduced calorie intake by about 25%, I joined a gym, I work out about 3-4 days a week, and take a 30 minute walk almost every single day. I cannot lose one pound.

    This past weekend I barely ate anything but slim fast shakes, and I worked out like a mad woman at the gym doing cardio (stair climber, rowing machine, elliptical, weights). My scale says I gained a pound. I’m going to see a doctor to find out if there’s something wrong with my thyroid.

    The Prozac did wonders for my panic attacks and made them completely go away. But I had no idea I’d gain this much weight and that it would be impossible to lose. I’ve never been this heavy in my life.

    • Melissa September 27, 2016, 4:28 pm

      I hear you! I am the heaviest I have ever been in my life! I feel like I am trapped in someone else’s body. It is so effed up. I have struggled with depression most of my life, but now I am starting to feel worse b/c of how fat I am.

  • Jenni August 11, 2016, 3:43 am

    Started taking fluoxetine 10mg in January 2014 after the birth of my daughter. I experienced serious health complications and basically missed the first 5 weeks of her life. Needless to say, the doctors thought I could use something to take the edge off. I took it for a year with no weight gain. I went off of it and gained 13 lbs.

    I went from 164 lbs post-birth to 177 lbs. I then went back on at 20mg because of horrible anxiety for six months. I lowered to 10 mg since and to date, I’ve gained almost 35 lbs. I am almost 200 lbs! I have never felt so bloated and full and gross. I’m looking for natural ways to ease anxiety and nightmares. Any suggestions?

  • Pauline August 20, 2016, 9:28 pm

    I have notice a big weight gain since being on Prozac. I walk 8 or 9 miles 5 days a week. I walk fast I feel I’m working hard. I also go to the gym 5 days a week. Whilst I have lost inches, I haven’t lost a pound, this is very depressing. I’m going to reduce these and finally stop.

  • Doreese September 23, 2016, 3:57 am

    I was on 20 mg daily for almost 1 year and gained 20 lbs. Just reduced dosage to 10 mg and think I will also cut back to 3-4 times a week. Initially cut back because I didn’t want to become too dependent on it, but now that I know it’s contributed to my craving for sweets and weight gain, I have another reason to stop. Thanks everyone for sharing your experience, it’s reassuring to understand what’s been happening to me.

  • Melissa September 27, 2016, 4:23 pm

    Like so many other people on this post, I am struggling with my weight and believe Prozac to be the main cause. I have always been petite and do accept that some weigh gain is due to age. For many years I took 20 mg most of the year, then increased to 40 mg for seasonal depression. After a really rough patch a few years ago I increased and never went back down.

    Now that I have been on 40 mg for several years, I have noticed a significant increase in weight gain! Research shows that the longer you are on Prozac, the more weight you can gain. I am sorry that all of you are suffering, but I feel better knowing that it is not just me.

    Although, I am nervous about the affects of decreasing my dosage I often feel like I am living in some one else’s body! I don’t feel like myself anymore and I take much better care of myself now than I did 10 years ago and I was easily 20 lbs lighter then.

  • Kenya October 5, 2016, 7:38 pm

    I have been taking the generic fluoxetine. I have been on increasing dosages for about 4 months. At first I actually lost my appetite and lost 10lbs. I was very sick. Over this past month my appetite has increased significantly. I eat and eat and eat. I crave so much sugar it’s not even funny. I have gained 5lbs.

    I have been trying to lose weight before going on the meds but now I am discouraged. I don’t want to go back to that depressed, stressed intolerable person but I also don’t want to blow up again. I was down 40lbs! I was trying so hard. I have spoken with my doctor. Still awaiting her response to this matter.

  • Mn October 19, 2016, 1:05 am

    I gained about 40 lbs the two times I was on Prozac. The first time I was on it for about two years but the second I was only on it for about seven months and I still gained a lot of weight. It helped with my anxiety, but the weight gain was too much. I won’t take it again. I’m glad to hear I was not the only one that gained weight on it.

  • Twirl58 November 6, 2016, 4:29 pm

    Have been on 20mg Fluoxetine for 13 months and have gained 10lb, this after having lost 42lb 3 years ago. I think it is because I feel like my old self and consequently am eating like old self. Can relate to having a wardrobe full of clothes that are too uncomfortable to wear and am reduced to a couple of pairs of elasticated waist trousers and baggy tops. I am fed up with dressing like a fat person again and have stopped taking the tablets completely after reducing them to 3 times a week. I am determined to wear my lovely clothes again, wish me luck. 🍀

  • susan vazzano November 14, 2016, 9:44 pm

    Been on pro for 4 mths. Have gained 12 lbs… too much.

  • Debbie November 15, 2016, 10:22 pm

    So so glad to find this website. I had been feeling for the last few months that I was just a loser and couldn’t do anything right. I have taken anti-depressants for 10 years, when I started taking them I weighed 96 lbs. I now weigh 171. I also go to the doctor’s diet program, where they prescribe phentermine diet pills. Really all that has done for the last few months is just help me not gain anymore.

    I was gaining 10 lbs every 6-8 weeks, I am assuming that it has to do with my doctor upping my prozac from 40mg – 60mg. I eat less than 1100 calories a day and walk about 3 times a week. I weaned myself off of the prozac (fluoxetine) on October 27th, so it has only been about 2 & 1/2 weeks, I sure hope it doesn’t take too long to get a little of this weight off.

    I have about 4 pieces of clothing that fit me now. I am in a size 14. Can’t afford to go out and buy new clothes.

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