Medications and Weight Gain: What You Should Know

Managing your health involves a balance of medication and lifestyle. If you're concerned about weight gain as a side effect of your prescriptions, discuss it with your doctor. They can help you explore alternatives or integrate diet and exercise to find the best plan for you.

Have you ever started a new medication and noticed the number on the scale creeping up? You’re not alone. Many prescription medicines can cause weight gain as a side effect. This can feel frustrating, especially if you’re working hard to eat well and stay active.

The good news is—understanding why this happens, and knowing what you can do about it, can help you take back control.

Why Do Some Medications Cause Weight Gain?

Noticing unexpected weight gain after starting a new prescription? You aren't alone. Medications can sometimes affect appetite or metabolism. If you have concerns, talk openly with your doctor about alternatives or lifestyle changes that can help you manage your weight.

Medicines can affect weight in different ways:

• They may increase appetite, so you feel hungrier.

• They can slow down metabolism, changing how your body uses energy.

• Some make the body hold on to extra fluid.

The effect depends on the type of medicine, the dose, and how long you take it.

Medicines That May Cause Weight Gain

Not everyone will gain weight, but these are some common categories:

• Diabetes medicines – Certain insulin and pills (like glipizide or pioglitazone) may lead to weight gain.

• Antidepressants – Some older antidepressants (like amitriptyline, paroxetine, mirtazapine) are more likely to cause weight gain.

• Antipsychotics – Medicines such as olanzapine, quetiapine, risperidone, and clozapine can increase weight.

• Seizure medicines – Gabapentin, pregabalin, valproic acid, and carbamazepine are linked to weight gain.

• Steroids – Long-term use of prednisone or similar drugs may cause increased weight and fluid retention.

• Blood pressure medicines (beta-blockers) – Drugs like metoprolol, propranolol, and atenolol may contribute.

• Hormones and contraceptives – Some injections (Depo-Provera) and hormone therapies may cause weight gain.

• Allergy medicines – Older antihistamines (like diphenhydramine) can sometimes increase appetite and weight.

What Can You Do?

• Talk to your healthcare provider

  If you notice weight gain after starting a medicine, don’t stop taking it on your own. Instead, ask your provider if there are alternatives with fewer side effects.

• Make lifestyle changes

  Healthy eating, regular activity, and tracking your weight can help offset medication-related weight gain. Even small daily changes—like walking after meals or cutting back on sugary drinks—make a difference.

• Adjustments may be possible

  Sometimes your provider can lower the dose or switch you to a different medication. Always discuss changes before making them.

• Additional help

  In certain cases, another medication (like metformin) may be added to balance out weight-related side effects, especially with antipsychotics.

When to Seek Help

If you gain more than 5 pounds in a month or more than 7% of your body weight, talk to your provider. Sudden or unexpected weight gain may mean your medication needs to be reviewed.

Remember

Not everyone gains weight from these medicines, and sometimes the health benefits of the treatment outweigh the risks of a few extra pounds. The most important step is open communication with your healthcare team.

👉 If you have concerns about your medicines and weight, don’t hesitate to ask your doctor. Together, you can find a plan that works for your health and your lifestyle.