Can Cymbalta cause weight gain?

Major depressive disorder (MDD) affects over 8% of American adults yearly. Cymbalta (duloxetine) is an SNRI antidepressant also used for anxiety and chronic pain. Like other antidepressants, it can cause weight changes—some people gain weight, others lose appetite and weight. Most weight gain is minimal but can be bothersome.

What is Cymbalta?

Cymbalta is a serotonin and norepinephrine reuptake inhibitor taken once daily in delayed-release capsules. It is FDA-approved for:

• Major depressive disorder
• Generalized anxiety disorder
• Diabetic peripheral neuropathy
• Fibromyalgia
• Chronic musculoskeletal pain

Common side effects

• Nausea
• Drowsiness or fatigue
• Dry mouth
• Loss of appetite
• Excessive sweating
• Trouble sleeping
• Diarrhea or constipation
• Dizziness
• Stomach pain
• Low sex drive or sexual dysfunction

Rare but serious effects include suicidal thoughts, low blood pressure, liver damage, serotonin syndrome, severe skin reactions, low sodium, seizures, worsening glaucoma, urinary problems, and discontinuation syndrome if stopped abruptly.

How does Cymbalta affect your body weight?

Antidepressants often cause weight gain more than weight loss. MAOIs and TCAs carry the highest risk. SNRIs and SSRIs vary: some (paroxetine, mirtazapine) cause significant gain, while others (sertraline, fluoxetine, venlafaxine, escitalopram, bupropion) are more weight-neutral.

Clinical studies of Cymbalta show:

• Short-term weight loss during the first 5 months of treatment
• Long-term weight gain after one year of use
• In children, 14–16% experienced weight loss; weight gain is not reported in pediatric labeling

How can I prevent weight gain from Cymbalta?

• Eat a healthy, low-calorie, low-fat diet rich in fruits, vegetables, and whole grains
• Get regular exercise; consult your provider before starting new routines
• Maintain good sleep habits (7–9 hours per night)

If weight gain persists, talk to your provider about adjusting medication or further strategies.

Sources

• Lee SH et al. Is increased antidepressant exposure a contributory factor to the obesity pandemic? 2016. Accessed Apr 11, 2025.
• Tourian KA et al. Desvenlafaxine and weight change in MDD. Primary Care Companion J Clin Psychiatry. 2010. Accessed Apr 11, 2025.
• Wise TN et al. Effects of duloxetine on body weight: analyses of 10 clinical studies. PCC J Clin Psychiatry. 2006. Accessed Apr 11, 2025.
• Cymbalta [package insert]. Lilly USA, LLC. Last updated 8/2023. Accessed Apr 11, 2025.
• Duloxetine [package insert]. American Health Packaging. Last updated 3/2025. Accessed Apr 11, 2025.