An honest comparison
Orlistat (Xenical / Alli) vs Phentermine
Orlistat (Xenical / Alli) and Phentermine both target weight loss and metabolic health — but through different mechanisms, with different evidence bases, and for different populations. The honest comparison favours one over the other only for specific reader profiles; for many adults, the right answer is "neither, here's what fits."
At a glance
| Metric | Orlistat (Xenical / Alli) | Phentermine |
|---|---|---|
| Sustainability | 4/10 | 3/10 |
| Short-term effect | 5/10 | 6/10 |
| Long-term effect | 4/10 | 4/10 |
| Cost / month | ~$70 | ~$30 |
| Visible results | ~30 days | ~14 days |
| Evidence quality | strong | moderate |
Who should pick Orlistat (Xenical / Alli)
Orlistat (Xenical / Alli) fits adults who adults willing to combine with a low-fat diet (the side effects are mainly when high-fat meals are consumed).
Who should pick Phentermine
Phentermine fits adults who adults with moderate obesity who can't access glp-1 drugs (cost, supply, insurance), as a short-term boost.
The honest verdict
Orlistat (Xenical / Alli) scores 4/10 on sustainability and 4/10 long-term, with strong evidence. Phentermine scores 3/10 sustainability and 4/10 long-term, with moderate evidence. They're roughly equivalent long-term in the literature. The choice should be driven by which one you can actually sustain.
Why both might fail you (and what to do instead)
Both can fail when the underlying drivers (sleep, stress, ultra-processed-food saturation, metabolic adaptation in repeat dieters) aren't addressed. If you've already tried both or one and bounced, the issue isn't macros — it's protocol fit. The Metabolic Damage Assessment maps your profile to a starter protocol that addresses the actual gap.
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Still not sure which fits?
The Metabolic Damage Assessment maps your profile to a starter protocol matched to your specific patterns — not a generic comparison.