Read Off Label rates the evidence for Orlistat as Strong and the benefit magnitude as low-med, producing an overall grade of B (6.9/10). XENDOS trial: modest weight loss (~3% above placebo at 4 years) and ~37% reduction in progression to T2D.

Orlistat has a low-med risk profile in published human data. Legal status: OTC (Alli) / Rx (Xenical). This is not medical advice — see the disclaimer.

Orlistat

Metabolic Health · Lipase inhibitor

Also known as: Xenical ·Alli

Tier B

Reviewed by Read Off Label · Last reviewed Jun 7, 2026 · How we grade

lipase-inhibitorotc

6.9 / 10

Tier B

Ev 8 Bn 3.5 Sf 7

Bottom line

Read Off Label grades Orlistat as B (6.9/10) based on strong evidence, low-med benefit magnitude, and a low-med-risk safety profile.

XENDOS trial: modest weight loss (~3% above placebo at 4 years) and ~37% reduction in progression to T2D.

Typical use: 60 mg (OTC) or 120 mg TID with meals — OTC (Alli) / Rx.

What this is

XENDOS trial: modest weight loss (~3% above placebo at 4 years) and ~37% reduction in progression to T2D. Steatorrhea and "anal leakage" are common and notorious. Now largely displaced by GLP-1 era drugs.

Mechanism

Inhibits pancreatic/gastric lipases — prevents absorption of ~30% of dietary fat; unabsorbed fat excreted in stool

Dose & route

60 mg (OTC) or 120 mg TID with meals

Citations

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Common questions

Does Orlistat work?: Read Off Label rates the evidence for Orlistat as Strong and the benefit magnitude as low-med, producing an overall grade of B (6.9/10). XENDOS trial: modest weight loss (~3% above placebo at 4 years) and ~37% reduction in progression to T2D.
Is Orlistat safe?: Orlistat has a low-med risk profile in published human data. Legal status: OTC (Alli) / Rx (Xenical). This is not medical advice — see the disclaimer.
What is the typical dose for Orlistat?: 60 mg (OTC) or 120 mg TID with meals
How does Orlistat work?: Inhibits pancreatic/gastric lipases — prevents absorption of ~30% of dietary fat; unabsorbed fat excreted in stool

This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.