Initially, you may lose a small amount of weight, about 1 kg (2.2 lb) on average, when you first start taking Prozac, but over the long-term you may gain that weight back or even add on extra weight up to 6 kgs (13.2 lbs). Studies suggest this may be due to a recovery of your appetite after your symptoms subside.
Prozac is linked to weight loss, especially early in treatment. Studies show that when people begin treatment with Prozac, they could experience a modest weight loss of about one pound. This weight loss will be observable about one month after beginning treatment.
Results: We included 19 trials (2,216 adults) and found that fluoxetine may reduce weight by −2.7 kg (95% CI −4 to −1.4; p < 0.001) and body mass index by −1.1 kg/m2 (95% CI −3.7 to 1.4), compared with placebo; however, it would cause approximately twice as many adverse events, such as dizziness, drowsiness, fatigue, ...
Studies have shown that the use of the antidepressant Prozac can cause an acute loss in weight among those taking the drug to treat major depressive disorders. This may be due to the effect of the drug on serotonin, an appetite suppressant.
Prozac® (fluoxetine) can cause weight loss and/or decreased appetite in some patients but many find that it has little or no effect on their weight long-term.
Fluoxetine increases resting energy expenditure and basal body temperature in humans.
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.
Bupropion (Wellbutrin), an atypical antidepressant, works by altering the brain chemicals norepinephrine and dopamine. In addition to being the only antidepressant consistently associated with weight loss, it's also associated with fewer rates of sexual side effects and sexual dysfunction than SSRIs and SNRIs.
Switching to a Mediterranean diet - one which includes fruits, vegetables, nuts, seeds, whole grains, and fish - may not only reverse the weight gain caused by your antidepressant but also help to treat the symptoms of your depression.
Antidepressants like fluoxetine help to improve your mood so you feel better. You may notice that you sleep better and get on with people more easily because you're less anxious. You will hopefully feel less worried. Fluoxetine will not change your personality, it will simply help you feel like yourself again.
Does Prozac affect metabolism? Prozac does not directly change the way that metabolism works. The weight gain associated with Prozac is not because it suppresses metabolic function.
Bottom Line. Within the first one to two weeks, most people feel lower levels of anxiety, restlessness or tiredness with Prozac treatment. Your sleep, energy and appetite may improve over the first month and you may have a better focus on daily tasks.
It has been observed that some antidepressants can affect estrogen levels in women. For instance, selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine (Prozac) and sertraline (Zoloft) have been shown to decrease estrogen levels in women.
The SSRI fluoxetine (Prozac) and the SNRI duloxetine (Cymbalta) can lead to a decrease in appetite and slight weight loss during the first months of treatment. Bupropion (Wellbutrin), which works by blocking norepinephrine and dopamine, may also have this effect.
Which antidepressants are less likely to cause weight gain? Fluoxetine (Prozac) and sertraline (Zoloft and Lustral) are two antidepressants often less likely to cause weight gain.
Increasing both aerobic exercise and strength training, ideally four times a week for a minimum of 30 to 45 minutes, can increase muscle tone and metabolism and reduce fat stores. Regular exercise has also been shown to reduce risk for depression relapse when combined with a stable medication regimen.
As an SSRI, Prozac works by preventing the brain from reabsorbing naturally occurring serotonin. Serotonin is involved in mood regulation. In this way, Prozac helps the brain to maintain enough serotonin so that you have a feeling of well-being, resulting from improved communication between brain cells.
Antidepressants interfere with serotonin, the neurotransmitter that regulates anxiety and mood while also controlling appetite. In particular, these changes may increase cravings for carbohydrate-rich foods, such as bread, pasta, and desserts.
Fifteen depressed patients treated with SSRIs (fluoxetine, paroxetine and sertraline) who had developed sexual dysfunctions, showed a high percentage of emotional blunting (80%), including a decrease of creativity, sexual pleasure, interest in sex, ability to cry, expression of their own feelings.
You can feel drowsy in the first few days of taking fluoxetine. However, it should get better after the first week or two. You may become more anxious, or it may make you irritable. This should settle after a couple of weeks.
Prozac can make you feel more optimistic, improving mood, appetite, sleep, focus and energy levels. It may also decrease anxiety, fear, unwanted thoughts and panic attacks.
Other research suggests that fluoxetine may be “particularly unproblematic” when people stop taking it because of its especially long half-life of 96–144 hours, which equates to 4–6 days. A drug's half-life refers to the time it takes for the amount of the medication's active substance to reduce by half in the body.
It has been reported that antidepressant drug reactions result in the hyperpigmentation of the skin and fluoxetine can promote hair follicle pigmentation [20]. In addition, there are side effects when fluoxetine is used as a drug for skin hypopigmentation disorders.