As a physician, I often meet patients who are discouraged by weight gain that doesn’t seem to make sense. They may be eating well, exercising regularly, and still the scale keeps moving up. Lifestyle choices matter a great deal. Medications and supplements can matter just as much, and knowing which ones affect weight is worth raising with your own doctor, because the cause can be hiding in plain sight.
Certain prescriptions are known to promote weight gain. Diabetes medications are a good example: insulin, sulfonylureas like glipizide, and thiazolidinediones like pioglitazone often push weight up. Metformin, GLP-1 receptor agonists like semaglutide, and SGLT-2 inhibitors tend to do the opposite and help with weight control.
I’ve also seen this pattern with antidepressants. Drugs like escitalopram, citalopram, or paroxetine can add pounds, as can tricyclics such as amitriptyline. Even trazodone or mirtazapine carry this risk. For some patients, switching to bupropion, fluoxetine, or sertraline makes a noticeable difference.
Atypical antipsychotics are another tricky class. Olanzapine, risperidone, and quetiapine are all associated with weight gain, while ziprasidone tends to have less impact. Anti-epileptic drugs split the same way. Same pattern, different receptors. Valproic acid and gabapentin tend to increase weight; topiramate and lamotrigine usually don’t.
Even medications outside psychiatry and neurology come up in this discussion. Lithium, commonly used as a mood stabilizer, often causes weight gain, and so do glucocorticoids like prednisone, especially with longer courses. Beta blockers such as metoprolol and propranolol carry the same issue, carvedilol usually has less effect, and antihistamines like diphenhydramine or cetirizine can shift weight too, though loratadine tends not to, which is worth remembering the next time an allergy prescription gets refilled without a second thought. Hormonal contraception adds another layer: depo-medroxyprogesterone is linked to weight gain, which can be genuinely frustrating for patients who are otherwise doing everything right. Non-hormonal methods are an option worth raising.
Over-the-counter medications and supplements belong in this conversation too, right alongside anything prescribed. Chronic antihistamine use may interfere with appetite regulation. Proton pump inhibitors, like omeprazole, can indirectly affect weight through changes in gut microbiota. Long-term NSAID use may lead to water retention. Some “energy” or “muscle gain” supplements hide hormones or steroids that work against weight control entirely.
This is why reviewing medications matters so much in a weight conversation. Weight gain gets blamed entirely on diet or activity when the real trigger may be sitting in the pillbox. Of course, no one should stop a medication on their own. Sometimes the benefit outweighs the side effect. Sometimes there’s a safer alternative that gets the same result without the tradeoff.
Bringing medications into the conversation gives us a fuller picture. It lets us make thoughtful adjustments while still focusing on lifestyle. It’s about tailoring a plan that actually supports long-term health, one a patient can live inside for years.
Sources:
- Saunders KH, Igel LI, Shukla AP, Aronne LJ. Drug-induced weight gain: rethinking our choices. J Fam Pract. 2016;65(11):780-788. PMID 28087864. https://pubmed.ncbi.nlm.nih.gov/28087864/
Board Certified in Obesity Medicine and Family Medicine
This blog is for educational purposes only and does not constitute individual medical advice. Always consult your own physician before making changes to your health, medications, or treatment plan.
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