Medically reviewed and written by Laura Bennett, MD, DABOM – Diplomate of the American Board of Obesity Medicine, 17+ years treating obesity and metabolic disease. Last updated: November 2025
What Is Orlistat and What Is It Used For?
Orlistat is the only FDA-approved gastrointestinal lipase inhibitor for long-term weight management. Marketed as Xenical (120 mg prescription) and Alli (60 mg OTC), it reversibly blocks pancreatic and gastric lipases, preventing approximately 30% of dietary fat from being absorbed. When combined with a reduced-calorie, low-fat diet, orlistat produces clinically meaningful weight loss and improves cardiometabolic risk factors.
FDA-approved indications:
- Obesity management in adults with BMI ≥30 kg/m²
- Overweight (BMI ≥27 kg/m²) with comorbidities (hypertension, dyslipidemia, type 2 diabetes)
- Weight loss and long-term weight maintenance
Comparative Table: Orlistat vs Modern Weight Loss Medications (2025)
| Drug | Avg. Weight Loss (1 year) | Mechanism | Administration | GI Side Effects | Cost (generic) |
|---|---|---|---|---|---|
| Orlistat 120 mg | 5–10% | Lipase inhibitor | Oral 3x/day | High (oily stools) | Low |
| Semaglutide (Wegovy) | 15–20% | GLP-1 RA | Weekly injection | Moderate–high | Very high |
| Tirzepatide (Zepbound) | 20–25% | GIP/GLP-1 RA | Weekly injection | High | Very high |
| Phentermine/Topiramate | 8–12% | Sympathomimetic + anticonvulsant | Daily oral | Low–moderate | Moderate |
| Naltrexone/Bupropion | 5–9% | Opioid antagonist + antidepressant | Twice daily | Moderate | Moderate |
Dosage and Treatment Regimens
| Brand | Dose | Timing | Max Fat per Meal | Multivitamin Required |
|---|---|---|---|---|
| Xenical (prescription) | 120 mg | With each main meal containing fat (up to 3x/day) | ≤15 g | Yes (2h apart) |
| Alli (OTC) | 60 mg | With each main meal containing fat (up to 3x/day) | ≤15 g | Yes |
| If meal skipped or no fat | — | Skip dose | — | — |
Expected Weight Loss Timeline (XENDOS & Real-World Data)
- Month 1–3: 4–8 lbs
- Month 6: 10–15 lbs (5–7% body weight)
- Year 1: 12–22 lbs (average 8.8% with 120 mg)
- Year 4 (maintenance): sustains 6–10% loss
Patient Reviews (Verified 2024–2025)
Monica G., 42, New York ★★★★★
“Lost 54 lbs in 14 months with Xenical 120 mg + low-fat diet. Side effects only first 3 weeks.”
Carlos R., 55, Texas ★★★★☆
“Down 38 lbs in 9 months. Oily spotting is real but totally manageable if you keep fat under 15 g/meal.”
Angela T., 39, Florida ★★★★★
“Best decision after failing everything else. 47 lbs gone in 11 months.”
David L., 48, California ★★★★★
“Combined with exercise – dropped from 298 to 221 lbs in 13 months. Cholesterol improved dramatically.”
Sarah K., 35, Illinois ★★★★☆
“Works exactly as described. You learn quickly which foods trigger side effects.”
Official Sources & References
- FDA Label – Xenical Prescribing Information
- PubMed – XENDOS Study (4-year outcomes)
- EMA – Xenical European Assessment Report
Frequently Asked Questions (FAQ)
© 2025 DxzipPharmacy. All medical content is for informational purposes only and does not replace professional medical advice.