Prozac and Weight Loss

by on May 18, 2012

Weight Loss is a side effect has been reported by patients taking Prozac (Fluoxetine).  In clinical studies of Prozac, up to two percent of subjects reported small decreases in their body weight.   Additionally, a 2004 study reported that of 2,000 patients with Type 2 diabetes, those taking Prozac lost on average twice as much weight as other patients taking Xenical.

Causes of Weight Loss

In spite of the numbers of successful antidepressant drugs on the market, it is not known how they actually work. A neurotransmitter called serotonin is targeted by Prozac and it is believed that prolonging the action of serotonin in brain cell synapses alleviates symptoms of depression. But the actual “how” is unknown. Serotonin is believed to have an impact on appetite but how it does this is unknown. So if serotonin affects appetite and Prozac affects serotonin, could it be that Prozac causes weight loss? Making a conclusion from two unknowns does not hold up to scrutiny.

There are no studies to quote on Prozac’s relationship to weight loss. Some experts say that weight loss “appears” to be a side effect of taking Prozac. Others state that weight loss is “possible” when Prozac is prescribed. In an attempt to capitalize on a perceived side effect, some doctors have even prescribed Prozac to patients specifically for weight loss. But with so many unknowns regarding the inner workings of serotonin and Prozac it cannot be said with certainty that Prozac and weight loss go hand in hand.

People who are chronically depressed tend to search for comfort in unlikely places. Any pleasurable activity can cause a release of serotonin in the brain, so continuance of the activity tends to produce welcome improvements in mood. One activity that releases serotonin is eating. The satisfaction from eating and obtaining a feeling of fullness can be prolonged by eating more, and eating often. This behavior of course leads to weight gain. Some people who begin to treat their depression with Prozac will no longer need to overeat and begin to lose weight.

Some patients might experience some initial weight loss due to a decreased appetite while taking Prozac. Others may stop overeating due to an improved mood and better self esteem while taking Prozac. But Prozac alone does not alter the way a body metabolizes food or burns calories and cannot be relied upon to cause weight loss.