Medically reviewed by Kristin Hall, FNP
Written by Our Editorial Team
Last updated 6/2/2022
If you’ve been diagnosed with major depressive disorder (MDD), generalized anxiety disorder (GAD), social anxiety disorder (SAD) or panic disorder (PD), your mental health provider may prescribe the medication Effexor XR® to help you manage your symptoms.
Effexor is an antidepressant. Like many other antidepressants, it can potentially cause some side effects. However, unlike with most medications for depression, reports of Effexor weight gain aren’t very common.
In fact, some scientific research suggests that Effexor is more likely to contribute to mild weight loss than noticeable weight gain.
Below, we’ve explained what Effexor is, as well as how it works as a medication for depression and anxiety. We’ve also discussed whether Effexor can cause weight gain, appetite changes or other changes in your eating habits.
Finally, we’ve talked about what you can do to maintain a healthy weight while using Effexor or similar medication to treat major depression or anxiety
Effexor, which contained the active ingredient venlafaxine, was an antidepressant used to treat depression and anxiety disorders, including generalized anxiety disorder, social anxiety disorder and panic disorder.
The Food and Drug Administration (FDA) first approved Effexor in 1993. Although the original medication is no longer available in the United States, venlafaxine is still sold as a generic drug and in extended-release form as Effexor XR®.
Venlafaxine, the active ingredient in Effexor, belongs to a class of antidepressants referred to as serotonin-norepinephrine reuptake inhibitors, or SNRIs. Like other antidepressants, it works by changing the levels of certain natural chemicals, called neurotransmitters, in your brain.
More specifically, venlafaxine works by increasing levels of the neurotransmitters serotonin and norepinephrine.
As a neurotransmitter, serotonin plays an important role in regulating your moods, your feelings of happiness and your levels of anxiety. It also helps manage your sleep cycle by stimulating the parts of your brain that cause you to feel tired at night and alert in the morning.
Normal serotonin levels are associated with a stable mental state. However, low serotonin levels are linked to an elevated risk of depression, anxiety, obsessive-compulsive disorder and suicidal thoughts and/or behavior.
Norepinephrine, or noradrenaline, is responsible for increasing your attention and focus, helping you form memories and recall information, and managing your sleep-wake cycle and general level of mental alertness throughout the day.
It also plays a key role in promoting proper cardiovascular function by increasing your heart rate and blood pressure when your body needs more energy.
Low levels of norepinephrine are associated with many signs of depression in women, including feelings of tiredness and lethargy, difficulty focusing and a reduced overall mood. Many people with low norepinephrine levels also suffer from other mental health issues, such as anxiety.
Experts believe that by increasing your levels of serotonin and norepinephrine, Effexor XR and generic venlafaxine can reduce the severity of many symptoms of depression and anxiety.
Like several other antidepressants, venlafaxine is also used off-label to treat medical conditions other than those for which it’s approved by the FDA. These include hot flashes, several forms of chronic pain and premenstrual dysphoric disorder (PMDD).
If you’ve ever looked into the common side effects of antidepressants, you’ve most likely seen weight gain somewhere on the list.
It’s no secret that many antidepressants are associated with some degree of weight gain, often a significant amount. However, this issue is generally more common with older antidepressants than with newer medications such as Effexor XR®.
Several different types of antidepressants are available, each with their own risk of certain side effects. Common types of antidepressants include:
Selective serotonin reuptake inhibitors (SSRIs). These popular antidepressants work by increasing serotonin levels. They’re modern drugs that are generally used as first-line treatments for depression.
Serotonin-norepinephrine reuptake inhibitors (SNRIs). These antidepressants work by increasing serotonin and norepinephrine levels. Like SSRIs, they’re newer, modern medications that are often used as first-line treatments for depression.
Tricyclic antidepressants (TCAs). Tricyclic antidepressants are older medications that first came onto the market in the 1950s. Due to their significant risk of side effects, most tricyclic antidepressants aren’t used as first-line depression treatments today.
Monoamine oxidase inhibitors (MAOIs). MAOIs are another older class of drugs from the 1950s and, like TCAs, they can cause side effects and drug interactions and aren’t used as first-line treatments for depression today.
Other antidepressants. Some antidepressants, such as bupropion XL, don’t always fit into an obvious category. These drugs are sometimes called “atypical” antidepressants due to their unique mechanism of action and effects.
Our full guide to depression medications provides more information on how these medications work, as well as their key differences.
The risk of weight gain varies hugely between different antidepressant drugs, with some more associated with weight gain than others.
For example, in one review and meta-analysis published in the Journal of Clinical Psychiatry in 2010, researchers found that the antidepressants amitriptyline, mirtazapine, and paroxetine all had a significant association with weight gain, whereas other medications did not.
In general, clinical studies don’t suggest that Effexor XR or generic venlafaxine are associated with significant weight gain.
For example, one large-scale, population-based study looked at the effects of several common antidepressant medications on weight, including venlafaxine.
Although the number of participants that used venlafaxine was small, there was little long-term change in weight observed. In fact, the researchers estimated that venlafaxine may contribute to a small amount of weight loss with long-term use.
Large-scale clinical trials of venlafaxine, which took place prior to its approval by the FDA, also failed to show any evidence of significant weight gain. Instead, most young people prescribed venlafaxine lost a small amount of weight (approximately one pound over eight weeks).
With this said, a small amount of research has found that venlafaxine may cause weight gain in some people. For example, a study published in the journal General Hospital Psychiatry in 2015 found a link between several antidepressants and weight gain, one of which was venlafaxine.
Overall, the link between Effexor XR, generic venlafaxine and weight gain isn’t very clear, with a mix of studies showing either weight gain, mild weight loss or no significant changes in average body weight.
This could mean that Effexor XR or generic venlafaxine are treatment options worth considering if you’re concerned about weight gain from other antidepressants.
Although weight gain from Effexor XR is not common, Effexor XR and generic venlafaxine still have the potential to cause side effects.
Common adverse effects of Effexor XR and venlafaxine include:
Somnolence (drowsiness or sleepiness)
Effexor XR and generic venlafaxine can also cause sexual side effects, including a reduction in your sex drive, difficulty achieving orgasm and other forms of sexual dysfunction.
Men who use Effexor XR or generic venlafaxine may experience sexual function issues such as erectile dysfunction (ED) and abnormal ejaculation.
Other potential side effects of Effexor XR and generic venlafaxine include headache, dizziness, weakness, nightmares, vomiting, diarrhea, heartburn, stomach pain, a change in your ability to taste food, loss of appetite, shaking, numbness or tingling and hot flashes or flushing.
Some people who use Effexor XR or generic venlafaxine also experience urination issues, such as frequent urination or difficulty urinating.
In rare cases, Effexor XR and generic venlafaxine may cause more severe adverse reactions or signs of an allergic reaction.
Contact your healthcare provider as soon as possible if you experience difficulty with breathing or swallowing, rash, hives, itchy skin, a fast or irregular heartbeat, chest pain, unusual bleeding or bruising, fever, sweating, blurred vision or seizures.
It’s also important to seek immediate medical help if you experience confusion, changes in your coordination, hallucinations or coma.
Like other antidepressants, venlafaxine may interact with other medications. When it’s used with other medications that increase serotonin levels, Effexor XR or venlafaxine may contribute to an increased risk of serotonin syndrome — a potentially serious side effect.
To avoid drug interactions while using Effexor XR or generic venlafaxine, make sure to tell your healthcare provider about all medications you currently use or have recently used, including all medications you’ve taken within the last 14 days.
It’s also important to closely follow your healthcare provider’s instructions and only use Effexor XR or generic venlafaxine at the prescribed daily dose.
While these side effects may sound alarming, it’s important to keep in mind that the majority of people who use venlafaxine do so safely without any issues.
Because Effexor generally doesn’t have as much of an effect on your eating habits or weight as other antidepressants, it shouldn’t be too difficult to maintain your normal body composition and weight while you’re using this medication.
Use the following tips to keep yourself healthy and maintain a steady weight while using Effexor XR or generic venlafaxine to treat psychiatric disorders such as depression or anxiety:
Eat a balanced, healthy diet. Many common nutrients in food, including fatty acids and proteins, can have an effect on your brain health and function. Research even suggests that many people with depression have poor eating habits.
Try to eat a healthy, balanced diet while you’re taking Effexor XR. Not only will this help you to maintain a consistent weight, but it may also improve your mood and assist you to recover from depression.
Keep yourself physically active. Exercise not only burns calories and helps to prevent weight gain — it also promotes an increase in endorphin production and changes in brain function that can make you feel better.
Try to keep yourself physically active, even if this just means going for a short walk every other day. Even a small amount of physical activity can have a big impact on your mental and physical wellbeing.
Avoid undereating. Although antidepressants are usually associated with an increased food intake and some degree of weight gain, it’s also possible to eat too little while you’re taking part in treatment for depression.
If you notice your weight starting to drop while taking Effexor XR or generic venlafaxine, try to increase your food intake until you’re able to comfortably maintain your usual body weight. And, of course, speak to your healthcare provider.
Don’t use weight loss supplements with Effexor XR. It’s important not to use weight loss agents with Effexor XR or generic venlafaxine. These supplements may cause side effects and increase your risk of experiencing safety issues.
Talk to your healthcare provider if you notice significant weight loss. According to clinical trials, just under 10 percent of people who use Effexor XR develop some degree of anorexia, an eating disorder characterized by not eating enough food.
If you suddenly no longer feel like eating, or feel like you should deliberately avoid food or exercise excessively, it’s important to get help as soon as possible by reaching out to your mental health provider for medical advice.
So Effexor doesn’t cause weight issues, then? Not exactly. In fact, Effexor has been found to be responsible for the opposite problem: it can cause unexpected or unnecessary weight loss.
How much weight loss is another question entirely. Clinical studies haven’t firmed up a number or percentage, and even in the last few years, the work done on antidepressant-related weight loss hasn’t really included enough venlafaxine users to arrive at any conclusions.
It’s entirely possible that one person could lose ten ounces and another ten percent of their body weight, but most of the study data suggests the amount might be negligible.
Perhaps a better question to consider is whether Effexor weight loss matters.
Look, we get that in the real world, there are many women (and men) who aren’t happy with their bodies, with their weight or with their health. So an antidepressant that can simultaneously lead to weight loss sounds great in theory, doesn’t it?
The problem, however, is that uncontrolled medication-induced weight loss is rarely healthy. And in addition to the side effects noted above, Effexor can be particularly dangerous for people who already have trouble keeping weight on, as well as for children who are still growing. In fact, it’s recommended that children avoid taking Effexor, since it can stunt growth.
And that’s not the only warning. In fact, there are warnings for people who are currently using weight loss drugs to avoid taking venlafaxine, and vice versa, as this drug combination may result in excessive weight loss, serotonin syndrome or cardiovascular problems like high blood pressure.
For a patient dealing with obesity or other weight gain issues, this medication may offer an unexpected benefit. But abusing that benefit or selecting this medication for that perceived beneficial outcome is… dumb.
Effexor isn’t necessarily a medication you should avoid or not avoid. If a healthcare provider is concerned with you being underweight, for instance, they may advise you to use something else. Or, a healthcare professional might prescribe you a different medication if your quality of life is negatively affected by Effexor side effects. But in other cases, Effexor might be the right antidepressant for you.
The reality is that treating depression is complicated, and as much as we’d like to give you a clear answer on whether or not you should take Effexor, you need to consider the larger, holistic portrait of your mental health — the stuff beyond pills.
Mental health medications are most effective when used in combination with other forms of treatment, like therapy. Well-known versions of therapy these days don’t look like the couch-and-Freud stuff you see on TV. In fact, cognitive behavioral therapy (CBT) — the most effective kind of therapy for many people with depression — is more like a training strategy for your brain than a feelings exploration.
CBT helps you learn to isolate depressive thoughts and ways of thinking and reprogram them over time. Medication may give you the chemical supply to be happy, but therapy is how you get your brain to start being happy.
And back to weight, the elephant in the room when it comes to depressive symptoms might be the effects of some of your lifestyle habits, like dietary choices, exercise, drug and alcohol use, tobacco use and social activity.
Let’s talk about the big picture for a moment: is your depression medication really the way you want to solve ongoing issues with your weight? Is a side effect of a mood stabilizer really the solution to weight problems? Do you even need to lose weight?
Questions like these are designed to make you think, but truth be told, you might not be able to answer them alone. Problems with your mental health and your weight can’t be diagnosed, addressed or resolved on your own. To do that, you need the support of a healthcare professional.
Healthcare professionals are there to help you consider the symptoms of depressive disorders and figure out if you may actually have one. From there, they can help you determine the right way to handle treatment.
The same goes for weight issues. These are professional concerns, and while you can easily improve your diet and exercise habits without medical care, medication is where the line has to be drawn. So get help from the right people.
Trying to do just that? Consider using our mental health resources guide to learn more about various mental illness symptoms, symptoms of depression and what treatments are out there. You can also learn about other types of antidepressant drugs like tricyclic antidepressants and selective serotonin reuptake inhibitors, as well as other medications designed to treat mental health conditions like panic disorder, generalized anxiety disorder, social anxiety disorder and bipolar disorder.
But if you’re ready to take the next step in solving the problem, consider clicking a different link — one toonline therapy.
Whether it’s physical or mental health, professionals are ready to help you with your worries. All you have to do is reach out.
Effexor XR, which contains the active ingredient venlafaxine, is one of several medications used as an effective treatment for the symptoms of anxiety and depression.
In general, the link between Effexor XR and weight gain isn’t clear. Some studies suggest that it may contribute to weight gain, while others suggest that it may cause weight loss or don’t show any significant changes in weight.
You can maintain a stable weight while using Effexor XR or generic venlafaxine by following the tips above. If you notice your weight changing while using this medication, it’s best to reach out to your healthcare provider for assistance.
We provide venlafaxine and other antidepressants online as part of our range of depression and anxiety medications, following a private consultation with a licensed healthcare provider who will determine if a prescription is appropriate.
We also offer a full range of online mental health services, including online therapy and support groups to help you deal with depression, anxiety, stress and other mental health conditions and concerns.
Interested in learning more about managing depression? Our guide to the best medications for depression goes into more detail about your treatment options, from SNRIs such as Effexor XR to other medications for lifting your mood and providing relief from your symptoms.