Med Consumer Watch
Mounjaro vs Qsymia for Weight Loss
Back to Articles
Research10 min readApril 5, 2026

Mounjaro vs Qsymia for Weight Loss

A detailed comparison of Mounjaro and Qsymia. Which weight loss medication is more effective and which has fewer side effects?

By Med Consumer Watch Team
Mounjaro (tirzepatide) and Qsymia (phentermine/topiramate) both help with weight loss, but they're very different medications. Here's how they compare.

Weight Loss Results

Head-to-head comparison: • Mounjaro: 20-26% average weight loss at maximum dose • Qsymia: 7-10% average weight loss at maximum dose Mounjaro produces significantly more weight loss in clinical trials.

How They Work

Different mechanisms:
  • Mounjaro - GLP-1/GIP dual agonist; mimics satiety hormones; slows digestion; improves insulin sensitivity
  • Qsymia - Stimulant (phentermine) plus anticonvulsant (topiramate); suppresses appetite through different pathways

Side Effects

Mounjaro side effects: • Nausea, vomiting, diarrhea • Constipation • Injection site reactions • Fatigue Qsymia side effects: • Tingling (paresthesia) • Cognitive effects ("brain fog") • Dry mouth • Constipation • Insomnia, anxiety

Both medications have serious contraindications. Qsymia carries significant birth defect risks; Mounjaro has thyroid tumor warnings.

Administration

How you take them: • Mounjaro: Weekly injection • Qsymia: Daily oral pill Some prefer pills; others don't mind weekly injections.

Cost

Typical costs: • Mounjaro: $1,000+/month without insurance • Qsymia: $200-300/month Qsymia is significantly cheaper, but produces less weight loss.

The Bottom Line

Mounjaro is more effective for weight loss but more expensive and requires injections. Qsymia is less effective but cheaper and oral. For maximum weight loss, Mounjaro wins. For those who can't access or afford GLP-1s, or who can't tolerate injections, Qsymia remains a viable option.

Sources & References

  • FDA - Mounjaro and Qsymia Prescribing Information

Medical Disclaimer

This article is for informational purposes only and is not intended as medical advice. Always consult with a qualified healthcare provider before making decisions about your health or medications. Individual experiences may vary.

Related Articles

Topiramate for Weight Loss

Read more

Best Appetite Suppressant

Read more
Back to All Articles

Enter to Win a $1,788 CoreAge Rx Gift Card

Enter for a chance to use it toward eligible CoreAge Rx products and services.

The gift card may be applied toward eligible CoreAge Rx products and services. Prescription products additionally require completing the intake process and evaluation by a licensed healthcare provider, who alone decides eligibility and treatment. Winning does not guarantee that you will qualify for a GLP-1 medication or any other prescription treatment.

No purchase necessary. Prescription products require provider evaluation and approval. See Official Rules. Official Rules · Gift Card Terms · Privacy Policy · Terms