Effexor Weight Gain And Loss: Why It Happens

Last Updated: March 25, 2024

Nena Messina Authored by Nena Messina, Ph.D.
0 sources cited

Venlafaxine is thought to be a weight-neutral drug in the medical literature. This is because it may cause some patients to gain pounds while others can lose them while being treated with Effexor. Most venlafaxine effects, including weight changes, are characteristic features of the entire SNRI class. Effexor weight gain or loss is most strongly correlated with treatment duration rather than the disorder being treated.

Effexor and Weight Gain

Does Effexor cause weight gain? Yes, like other SNRI antidepressants, it can often cause an increase in mass after long-term use. Some patients can experience Effexor weight gain within ten weeks of starting medical treatment, while others do it on a more long-term basis. Patients who experience it in the short term usually lose weight after the drug is discontinued. However, for those who gain it on a long-term basis, it is harder to lose pounds even after Venlafaxine is stopped. Short-term venlafaxine weight gain is thought to be caused more by changes in appetite: patients eat more due to improvement in their symptoms from the treatment. Long-term Effexor weight gain is more strongly linked to the drug’s metabolic and hormonal effects on the body, including carbohydrate cravings and the impact on the thyroid hormone system.

Depressed woman eating desserts in bed.

According to a study, during a 10-week treatment period, patients gained an average of 13 +/- 8.4 kg. Such gain may be observed within 2-3 weeks of starting the treatment. Other studies have found an increase of ≥7% over baseline is greater than 40% of the patients on Venlafaxine and other antidepressants. Long-term studies have found that the chronic use of antidepressants, including Venlafaxine, contributes to an increased risk of long-term gain of weight in the treated population.

Patients must carefully monitor body size changes and other metabolic indicators like changes in blood sugar levels, lipid profiles, etc. Patients must consult licensed physicians regarding any significant changes in the indicators mentioned above. If the patient is currently breastfeeding or pregnant, Effexor and pregnancy implications must be carefully considered before any dose modulation.

Effexor Weight Loss

Venlafaxine leads to losing pounds in patients in short-term trials of up to 10 weeks. Anorexia nervosa is an eating disorder characterized by reduced appetite and, therefore, reduced caloric intake. Anorexia is one of the side effects of Effexor, seen in about 15% of the patients. A small percentage of patients (6%) treated with the drug over several weeks have shown the loss of about 5% or more body mass.

While the drug can not be prescribed for pediatric patients, clinical trials have been conducted with these populations. Younger adults and pediatric patients (Ages 6-17) are more susceptible to Effexor weight loss. In clinical trials monitoring the use of Effexor for depression and generalized anxiety disorder (GAD), 18% of the patients treated with the drug lost at least 3.5% body weight compared to 3.6% of patients on placebo.

Woman lost weight on Effexor wearing old bigger jeans.

Venlafaxine weight loss is thought to be caused by treatment-associated anorexia. 15% of the adults treated with the drug showed treatment-associated anorexia, compared to only 2% of the adults on placebo treatment.

Factors Affecting the Body Size on Antidepressants

Venlafaxine affects many systems in the body, leading to several side effects. In this context, effects on appetite, the gastrointestinal system in general, the endocrine system, leptin appetite regulations system, etc., modulate the impact of the treatment on the body.

Changes In Appetite

One important cause of venlafaxine weight gain or loss is the change in appetite during treatment. A patient of any anxiety-mediated disorder may suffer from decreased appetite due to such a condition or eat compulsively. Therefore, when the patient sees benefit from treatment, it may either suppress or augment appetite based on previous symptoms. Also, recovery from depression disorders may be associated with increased social eating, improvement in food taste, etc. It may cause the patient to eat more and thus gain more.

In addition to the mitigation of disease symptoms, Venlafaxine may affect the body’s appetite regulation systems, including leptin and tumor necrosis factor. It leads to an increase in appetite, which is commonly seen with long-term treatment with Venlafaxine. This, in turn, causes venlafaxine weight gain.

Carbohydrate Cravings

Patients on Venlafaxine have reported cravings for fatty and sweet foods. These cravings may also be exacerbated by the effects of Venlafaxine on leptin and tumor necrosis factor systems. In addition to cravings for fatty and sweet foods, disruption of these systems with the treatment also contributes to the increased incidence of other metabolic disorders like diabetes mellitus, hypertension, etc., in the long term. Disruption of glucose metabolism in diabetes mellitus and disruption of salt balance associated with hypertension further potentiate cravings for carbohydrates and fatty foods, turning the effect into a vicious metabolic cycle.


Though rare, edema, especially of the peripheral tissues, is seen in some patients with prolonged venlafaxine use. This edema may be a contributing factor in Effexor weight gain.

Hormonal Effects

Effexor capsules alter the endocrine body balance. It modulates the thyroid hormone metabolism system, thereby affecting appetite and the utilization of stored fats and carbohydrates for energy production in the body. The thyroid hormone system is crucial to the body’s weight maintenance system, and any modification of this system leads to a significant change in the body.

Weight Change Prevention

Sustained long-term use of Venlafaxine can lead to Effexor weight loss or gain. However, many steps may be taken to mitigate this change and resultant metabolic issues in patients.

Dietary Advice

Patients taking Venlafaxine must work with prescribing physicians to modify diet/fluid-mineral intake to mitigate the metabolic and hormonal effects of Venlafaxine.

Increased Physical Activity

Increased physical activity has been shown to have an anxiolytic effect. In addition, increased physical activity can also help mitigate the metabolic and hormonal effects of Venlafaxine, in conjunction with dietary modifications. Finally, physical activity, especially resistance training, is beneficial for attaining ideal body size, irrespective of the individual’s treatment status.

Woman practicing yoga to return weight after effexor weight gain.

Behavioral Therapy

Cognitive-behavioral therapy helps mitigate the symptoms and severity of anxiety and depression-based disorders, thereby assisting patients in reducing the venlafaxine dose required. It is also extremely helpful in assisting patients with controlling compulsive eating issues like anorexia or other changes in appetite, which lead to body changes caused by long-term Effexor treatment. Behavioral therapy can also help mitigate any concomitant addiction that the patient is suffering, including Effexor and alcohol.

Switching To Another Drug

There is a clear connection between Effexor and weight gain. If the patient is suffering from significant body size changes during Effexor use, the physician may consider switching the patient to another drug. For instance, a doctor may compare Effexor vs. Cymbalta effects on the body and choose a drug with less impact on weight in a patient.

If there is a need to discontinue the drug due to significant body mass changes, then quitting Effexor cold turkey should be avoided because of severe health complications that may appear. Patients must work with a physician to slowly wean off the drug to prevent the precipitation of Effexor discontinuation syndrome.

If a patient is suffering from Effexor addiction, it’s recommended to find suitable drug addiction rehab centers and seek help. Patients would be provided with proper treatment for substance abuse according to each specific case.

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Page Sources

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Published on: November 29th, 2019

Updated on: March 25th, 2024

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