Home Health 25 Common Medications That Could Be Causing Your Weight Gain
Health By Chu E. -

Unintentional weight gain can be both frustrating and confusing, especially when you’re already making healthy lifestyle choices. Sometimes, the culprit may not be your diet or lack of exercise, but rather something hidden in your medicine cabinet. Many widely used prescription and over-the-counter medications list weight gain as a potential side effect, whether through increased appetite, a slower metabolism, or water retention. Recognizing these connections is the first step toward regaining control over your weight. In this article, we’ll explore 25 common medications that could be influencing your body weight—and what you can do about it.

1. Prednisone (Corticosteroids)

25 Common Medications That Could Be Causing Your Weight Gain
“A bottle of Prednisone pills prominently sits alongside informative pamphlets, underlining its essential role in treating inflammatory conditions.” | Image source: thuocdantoc.vn

Prednisone is a corticosteroid often prescribed for inflammation, allergies, and autoimmune disorders. A well-documented side effect of prednisone is weight gain, caused by increased appetite, water retention, and changes in how your body stores fat. Patients may notice rapid weight changes, especially during prolonged courses. Long-term use can make weight management more difficult and may even lead to fat redistribution in certain areas, such as the face and abdomen. Other steroids may produce similar effects, but prednisone remains one of the most common culprits. Read more from Mayo Clinic

2. Paroxetine (Paxil)

25 Common Medications That Could Be Causing Your Weight Gain
“Close-up view of Paroxetine pills, known as an effective antidepressant, neatly aligned on a clean steel surface.” | Image source: mantracare.org

Paroxetine, better known by its brand name Paxil, is a selective serotonin reuptake inhibitor (SSRI) prescribed for depression and anxiety. This particular antidepressant is frequently linked to notable weight gain. Research indicates that paroxetine may disrupt metabolism and stimulate cravings for carbohydrates, making it more likely to cause weight gain than other SSRIs such as fluoxetine. People taking Paxil often report gaining several pounds over time, which can be frustrating during treatment. For further insight, visit Harvard Health Publishing.

3. Insulin

25 Common Medications That Could Be Causing Your Weight Gain
A close-up of a hand preparing an insulin syringe, highlighting the daily routine of diabetes management. | Image source: thuocdantoc.vn

Insulin is essential for managing diabetes, but it often comes with the unwanted side effect of weight gain. This occurs because insulin helps the body store glucose as fat, particularly when blood sugar levels are kept under tight control. All types of insulin can contribute to this effect, making it a widespread concern among people with diabetes. Patients may find it challenging to balance effective glucose management with maintaining a healthy weight. Learn more at the American Diabetes Association.

4. Amitriptyline

25 Common Medications That Could Be Causing Your Weight Gain
A close-up view of amitriptyline tricyclic antidepressant pills, their distinctive shape and color neatly arranged in a blister pack. | Image source: ihs.org.vn

Amitriptyline, a tricyclic antidepressant, is commonly prescribed for depression, migraines, and nerve pain. One of its notable side effects is weight gain, often attributed to its sedative nature and its ability to boost appetite. Patients taking amitriptyline may find themselves eating more or feeling less motivated to be physically active. Compared to many newer antidepressants, the risk of weight gain is significantly higher with this medication. For more details, see this Cleveland Clinic resource.

5. Olanzapine (Zyprexa)

25 Common Medications That Could Be Causing Your Weight Gain
A blister pack of olanzapine tablets, an antipsychotic medication, lies neatly arranged on a clean surface. | Image source: medicamentcontreanxiete.com

Olanzapine, sold as Zyprexa, is an atypical antipsychotic used to treat schizophrenia and bipolar disorder. It stands out among antipsychotics for causing rapid and significant weight gain in many patients. This is primarily due to metabolic changes and an increase in appetite triggered by the medication. Weight gain with olanzapine often occurs within the first few months of treatment and can be difficult to manage. For a deeper look at this medication, visit the National Alliance on Mental Illness.

6. Gabapentin (Neurontin)

25 Common Medications That Could Be Causing Your Weight Gain
A close-up of gabapentin capsules scattered on a white surface, commonly used to relieve nerve pain. | Image source: youmed.vn

Gabapentin, commonly prescribed for nerve pain and seizures, has been associated with weight gain in some users. This side effect is thought to result from increased appetite and mild fluid retention, though it’s generally less severe than with certain antidepressants. Even so, patients should be aware of this possibility when starting gabapentin. Monitoring your weight and discussing any concerns with your doctor is advisable. For more side effect details, see this Drugs.com article.

7. Risperidone (Risperdal)

25 Common Medications That Could Be Causing Your Weight Gain
A close-up view of white risperidone antipsychotic tablets scattered across a reflective surface, highlighting their distinctive shape. | Image source: ambientebio.it

Risperidone, marketed as Risperdal, is frequently used to treat schizophrenia and bipolar disorder. Like other antipsychotics, it is associated with weight gain, although the effect is generally less pronounced than with olanzapine. The weight increase is likely due to a combination of increased appetite and shifts in metabolism. Patients should be mindful of these changes, especially during the early stages of treatment. For a comprehensive overview, refer to this MedlinePlus overview.

8. Mirtazapine (Remeron)

25 Common Medications That Could Be Causing Your Weight Gain
A prescription bottle labeled mirtazapine sits on a countertop, representing a commonly used antidepressant medication. | Image source: bmj.com

Mirtazapine, known by the brand name Remeron, is an antidepressant well-known for its tendency to increase weight more than many other similar drugs. Its appetite-stimulating effects are sometimes beneficial for patients who are underweight or have trouble eating. However, for others, this side effect can be a significant concern and may lead to rapid weight gain. If you’re prescribed mirtazapine, monitoring your appetite and weight is important. For more details, see this Psychiatry Advisor article.

9. Propranolol

25 Common Medications That Could Be Causing Your Weight Gain
A blister pack of propranolol tablets sits beside a prescription bottle, representing a common beta-blocker heart medication. | Image source: thuocdantoc.vn

Propranolol is a beta-blocker commonly prescribed for high blood pressure and various heart conditions. One of its potential side effects is a slowed metabolism, which can lead to modest weight gain over time. This is a trend seen with several medications in the beta-blocker class. While the weight increase is usually mild, it can still be concerning for some patients. For a thorough look at propranolol’s effects, visit this WebMD resource.

10. Lithium

25 Common Medications That Could Be Causing Your Weight Gain
A white pill bottle labeled “Lithium” sits open on a table, spilling out small round mood stabilizer tablets. | Image source: Photo by SHVETS production on Pexels

Lithium is a mood stabilizer frequently prescribed for bipolar disorder. A common side effect is weight gain, often resulting from increased thirst—which can prompt greater consumption of sugary beverages or snacks—and alterations in metabolism. The amount of weight gained can vary significantly from person to person, but many find it challenging to manage over the course of treatment. If you are taking lithium, regular weight monitoring and open communication with your healthcare provider is essential. For more information, see the National Institutes of Health.

11. Sulfonylureas (e.g., Glipizide, Glyburide)

25 Common Medications That Could Be Causing Your Weight Gain
A close-up view of white sulfonylurea tablets, a common oral medication used to manage type 2 diabetes. | Image source: youtube.com

Sulfonylureas, such as glipizide and glyburide, are oral medications used to help control blood sugar in people with diabetes. They work by stimulating the pancreas to release more insulin. This increased insulin production often leads to weight gain, making it difficult for some patients to manage their weight effectively. The effect is similar to what is seen with insulin injections. To learn more about how sulfonylureas may affect your weight, visit Johns Hopkins Medicine.

12. Quetiapine (Seroquel)

25 Common Medications That Could Be Causing Your Weight Gain
A silver blister pack of quetiapine tablets sits on a white surface, highlighting this essential antipsychotic medication. | Image source: thuocdantoc.vn

Quetiapine, marketed as Seroquel, is prescribed for mood disorders like bipolar disorder and schizophrenia. A frequent side effect of this medication is weight gain, which can be significant for some individuals. Studies have shown that quetiapine’s impact on weight is comparable to other atypical antipsychotics. Monitoring weight and discussing concerns with your doctor can help manage this effect. For additional information, see this Medscape reference.

13. Valproic Acid (Depakote)

25 Common Medications That Could Be Causing Your Weight Gain
A close-up view of white valproic acid pills, a common seizure medication, scattered across a reflective surface. | Image source: thuocdantoc.vn

Valproic acid, also known as Depakote, is commonly prescribed for seizures and bipolar disorder. A significant side effect of this medication is weight gain, which may result from increased appetite and changes in metabolism. Compared to some other anticonvulsants, valproic acid is more likely to cause noticeable weight increases. Patients taking this medication should be aware of these risks and discuss strategies for weight management with their healthcare provider. For more details, visit the Epilepsy Foundation.

14. Nortriptyline

25 Common Medications That Could Be Causing Your Weight Gain
A close-up view of prescription nortriptyline antidepressant pills, neatly arranged beside their labeled medication bottle. | Image source: wallpaperflare.com

Nortriptyline, a tricyclic antidepressant, is known for its potential to cause weight gain. This is mainly due to increased appetite and the sedative effects that can lower physical activity. While its impact is similar to that of amitriptyline, the degree of weight gain varies from person to person. If you’re concerned about this side effect, regular check-ins with your healthcare provider are recommended. For more specifics, see the Mayo Clinic information.

15. Carbamazepine (Tegretol)

25 Common Medications That Could Be Causing Your Weight Gain
A prescription bottle of carbamazepine anticonvulsant tablets sits on a countertop, ready for daily medication management. | Image source: wikidoc.org

Carbamazepine, sold under the brand name Tegretol, is prescribed for epilepsy and bipolar disorder. While weight gain can occur, it is generally less common than with medications like valproic acid. Some individuals may still notice changes in their weight during treatment, making regular monitoring important. Discussing any new or unusual weight changes with your doctor is always recommended. For more details on carbamazepine’s side effects, visit NHS UK.

16. Leuprolide (Lupron)

25 Common Medications That Could Be Causing Your Weight Gain
A healthcare professional prepares a syringe of leuprolide for hormone therapy, emphasizing careful handling and precise dosing. | Image source: medscape.com

Leuprolide, known by the brand name Lupron, is prescribed for hormone-sensitive cancers and endometriosis. A common side effect of this medication is weight gain, often resulting from hormonal changes and fluid retention. These shifts can make it difficult to maintain previous weight levels during treatment. Patients may also notice bloating or swelling as part of this effect. More information about leuprolide’s side effects can be found at this MedlinePlus resource.

17. Antihistamines (e.g., Diphenhydramine, Cetirizine)

25 Common Medications That Could Be Causing Your Weight Gain
A close-up of white antihistamine tablets in a blister pack, ready to provide fast allergy relief. | Image source: wtcs.pressbooks.pub

Certain antihistamines, particularly first-generation versions like diphenhydramine, are linked to weight gain. This is often due to increased appetite and the sedative effects that reduce overall activity levels. Second-generation antihistamines, such as cetirizine, may still cause some weight gain, but the effect is generally milder. If you notice changes in your weight while treating allergies, your medication could be a factor. For more information, see this helpful Healthline guide.

18. Metoprolol

25 Common Medications That Could Be Causing Your Weight Gain
A close-up of white Metoprolol tablets, a commonly prescribed beta-blocker used to manage heart conditions. | Image source: wikidoc.org

Metoprolol is a beta-blocker prescribed for high blood pressure and various heart conditions. Like other medications in its class, it can cause modest weight gain in some individuals. This effect is usually mild but may become noticeable over long-term use. Patients who are concerned about weight changes should discuss options with their healthcare provider. To explore more about metoprolol and its side effects, visit this Drugs.com overview.

19. Contraceptive Pills (Oral Contraceptives)

25 Common Medications That Could Be Causing Your Weight Gain
A close-up of a blister pack filled with colorful oral contraceptive pills, neatly organized for daily birth control. | Image source: flickr.com

Some oral contraceptives, particularly older versions, have been associated with weight gain. This is often due to fluid retention and shifts in hormone levels brought on by the medication. Fortunately, many modern, low-dose birth control pills tend to have less impact on weight. Still, some people may notice mild changes when beginning or switching pills. It’s always wise to discuss any concerns or noticeable weight changes with your healthcare provider. Learn more from this Planned Parenthood resource.

20. Pioglitazone (Actos)

25 Common Medications That Could Be Causing Your Weight Gain
A close-up of white pioglitazone diabetes medication pills scattered across a reflective surface, highlighting their smooth texture. | Image source: wikidoc.org

Pioglitazone, sold under the brand name Actos, is used to manage type 2 diabetes. A common side effect of this medication is weight gain, which typically results from fluid retention and increased fat accumulation. This effect is also seen in other drugs from the thiazolidinedione class. If you’re prescribed pioglitazone, it’s important to monitor your weight and discuss any concerns with your healthcare provider. For additional information, see this WebMD information.

21. Sertraline (Zoloft)

25 Common Medications That Could Be Causing Your Weight Gain
A close-up of sertraline tablets, a commonly prescribed SSRI antidepressant, neatly arranged on a clean white surface. | Image source: thuocdantoc.vn

Sertraline, known by the brand name Zoloft, is a widely prescribed SSRI antidepressant. Although weight gain with sertraline is generally less common than with medications like paroxetine, it can still occur, particularly during long-term treatment. Some individuals may notice gradual increases in weight over months or years. If you’re concerned about this side effect, ongoing communication with your healthcare provider is important. For further reading, check out this Verywell Mind article.

22. Clozapine (Clozaril)

25 Common Medications That Could Be Causing Your Weight Gain
A blister pack of clozapine tablets rests beside a prescription bottle, highlighting this essential antipsychotic medication. | Image source: tac.org

Clozapine, sold as Clozaril, is an antipsychotic typically used for treatment-resistant schizophrenia. Among all psychiatric medications, clozapine carries one of the highest risks for weight gain. The increase in weight is often greater than that seen with other antipsychotics like olanzapine or risperidone. This side effect can develop quickly and be difficult to manage without careful monitoring. To learn more, visit the National Institute of Mental Health.

23. Cortisone Injections

25 Common Medications That Could Be Causing Your Weight Gain
A healthcare professional administers a cortisone injection with a syringe to relieve persistent joint pain in a patient’s knee. | Image source: sportdoctorlondon.com

Cortisone injections are commonly used to relieve joint pain and inflammation. A possible side effect is temporary weight gain, typically caused by fluid retention rather than increased body fat. While most people experience only short-term changes, repeated or prolonged use can heighten this risk. It’s important to monitor your body’s response to cortisone and discuss any concerns with your healthcare provider. For more information, see this Cleveland Clinic information.

24. Tenofovir/Emtricitabine (Truvada)

25 Common Medications That Could Be Causing Your Weight Gain
A white pill bottle labeled Truvada stands open, revealing the blue HIV medication pills inside. | Image source: wikidoc.org

Tenofovir/emtricitabine, marketed as Truvada, is a cornerstone medication for HIV prevention and treatment. Some users experience weight changes, including weight gain, particularly when Truvada is combined with other antiretrovirals. The reasons for these changes can vary, and not all patients are affected in the same way. Regular monitoring and communication with your healthcare team can help address any concerns about body weight. For more details, refer to the AIDSinfo fact sheet.

25. Cyproheptadine

25 Common Medications That Could Be Causing Your Weight Gain
A close-up view of Cyproheptadine prescription antihistamine pills, neatly arranged beside their labeled medication bottle. | Image source: wikidoc.org

Cyproheptadine is an antihistamine that’s occasionally prescribed to help stimulate appetite, especially in underweight patients. As a result, weight gain is a well-recognized and often intentional side effect. For others taking cyproheptadine for allergy symptoms, this effect might be less desirable. If you notice a change in your appetite or weight while using this medication, speak with your healthcare provider. Find more information in this MedlinePlus overview.

Disclaimer

25 Common Medications That Could Be Causing Your Weight Gain
A bold medical disclaimer appears on a digital screen, reminding viewers to consult a doctor before making health decisions. | Image source: Photo by Alex Green on Pexels

This article is intended for informational purposes only and does not replace professional medical advice. Always consult your healthcare provider before making any changes to your medications or health routines. Your wellbeing deserves personalized, expert guidance—stay informed and proactive about your health.

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