Can fluoxetine cause weight gain?

While weight gain is not a common side effect of fluoxetine (brand name Prozac), it can occur in some patients. However, it is more common for fluoxetine to cause weight loss or have no effect on weight.

A study published in the Journal of Clinical Psychiatry found that about 25% of patients taking fluoxetine experienced weight changes, with some gaining weight and others losing weight. However, the overall effect on weight was small, with an average change of less than 2 pounds.

It is thought that the effect of fluoxetine on weight is related to its impact on appetite and metabolism. Some patients may experience increased appetite or cravings for high-calorie foods while taking the medication, which can lead to weight gain. However, others may experience decreased appetite or nausea, which can lead to weight loss.

If you are concerned about weight changes while taking fluoxetine, it’s important to talk to your healthcare provider. They can provide guidance on how to manage any changes in weight and may adjust your dosage or switch you to a different medication if necessary. It’s also important to maintain a healthy diet and exercise regularly to promote overall health and well-being.


There are various forms of drugs available, such as tablets or liquids, and each may have a separate patient information leaflet (PIL) for different doses. It is important to refer to the PIL for the specific form and dose of the drug that you have been prescribed.

You can search for further information and PILs on websites such as: