Prozac Weight Loss and Gain

Prozac is the brand name product of fluoxetine, an antidepressant that belongs to the class called the selective serotonin reuptake inhibitors, or SSRIs. You will need a doctor's prescription for this medication, used for treating depression, panic disorder and obsessive compulsive disorder. Your doctor might also prescribe Prozac to treat binge-eating and vomiting in patients who have moderate to severe bulimia, an eating disorder. In some cases, Prozac can cause either weight gain or weight loss.


Prozac increases the amount of serotonin, which a chemical found in the brain, by blocking its reabsorption into the body. This normalizes the level of serotonin in the body and promotes mental balance, according to PubMed Health.

Weight Loss

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Significant weight loss, especially in underweight depressed or bulimic individuals, may be an unwanted effect of treatment with Prozac. About 2 percent of patients may experience weight loss, according to eMed TV. This weight loss seen in some patients may be due to other side effects, including loss of appetite, nausea and dry mouth. Nausea is the most common gastrointestinal side effect, which may be present in up to 15 to 21 percent of individuals, explains.

Weight Gain

Prozac may also lead to an increased appetite and weight gain in about 1 to 10 percent patients, according to the “Drug Information Handbook.” Significant weight gain may lead to health concerns, such as the development of high blood pressure, high cholesterol and diabetes. Weight gain can also lead to increased depression and poor self-esteem.


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If you experience gastrointestinal side effects, take the medication with a meal. You may also chew gum or suck on hard candy to avoid dry mouth and nausea. Don't skip meals to avoid losing too much weight. If you lose 10 lbs or more without trying, speak with your physician right away. Weight gain can be prevented by eating a healthy diet and being active. Managing your caloric intake and exercising regularly can greatly reduce your risks of gaining weight. Your physician can help you develop a well-balanced diet and determine what exercises are right for you.


See your physician regularly to ensure proper monitoring of gastrointestinal side effects and weight loss or gain while taking Prozac. If weight loss or gain persists, your physician can determine if you need to to stop taking the drug or modify the dose.