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Foundayo vs Xenical

Quick read · 5 min

Last reviewed: September 2026Based on 2 clinical trialsEvery claim linked to source

Foundayo (orforglipron, daily pill) and Xenical (orlistat, capsule, three times daily with meals) are both approved for weight loss in the United States. No head-to-head trial has compared these two drugs. The figures below come from separate trials, each with its own participants, length and comparison group.

At a glance

Foundayo and Xenical compared on form, trial results, cost and reported side effects
 FoundayoXenical
FormDaily pill3x daily with meals
How oftenOnce-daily pill — no injection, no fasting, no food timingThree capsules daily, taken with each fat-containing meal
Weight loss in trialsUp to 12.4% — ATTAIN-1 (72 weeks)Up to 8.5% — Sjostrom 1-year RCT (52 weeks)
FDA approved20261999
Made byEli LillyRoche (Xenical) / GSK (Alli OTC)
How it worksA small-molecule (non-peptide) GLP-1 receptor agonist.Blocks pancreatic lipase enzymes in the small intestine, preventing approximately 30% of dietary fat from being broken down and absorbed.
Monthly cost, self-pay$149–$349/mo$40–$400/moover-the-counter strength; prescription runs to $400
Most reported reactionNausea 33% (ATTAIN-1)Oily/fatty stools (steatorrhoea) 27% (XENDOS)

Every figure in this table is read from the same trial and label records used everywhere else on this site.

Weight loss in each drug's main trial

No head-to-head trial has compared these two drugs.

Foundayo(orforglipron)12.4%

ATTAIN-1 (72 weeks)

Xenical(orlistat)8.5%

Sjostrom 1-year RCT (52 weeks)

In clinical trials, participants taking orforglipron lost on average up to 12.4% of their starting body weight, and participants taking orlistat lost on average up to 8.5%. Those numbers come from two different studies: ATTAIN-1 enrolled 3,127 adults with obesity or overweight with comorbidities, no type 2 diabetes over 72 weeks against placebo, while Sjostrom 1-year RCT enrolled 743 adults with obesity over 1 year (52 weeks) against placebo. Who took part, how long each trial ran and what each drug was measured against all move the percentage, so the two figures are not a measured difference between the drugs.

Monthly cost, self-pay

The bar spans the range in each drug's price record — lowest listed price to highest.

Foundayo$149–$349/mo

$149/month self-pay at the lowest dose, up to $349/month at the highest dose via LillyDirect. $25/month with the commercial insurance savings card. Medicare Part D coverage expected from July 2026 at ~$50/month.

Xenical$40–$400/mo

over-the-counter strength; prescription runs to $400

Prescription Xenical ~$200–$400/month; over-the-counter Alli (60mg) ~$40–$60/month.

Self-pay prices are what the manufacturer or the pharmacy lists, not what most people end up paying. Foundayo: $149–$349/month. Xenical: $40–$400/month. Insurance, dose and pharmacy all change both figures.

Side effects reported in the trials

ATTAIN-1 and XENDOS did not report the same reactions, so there is no shared row to line up. Each drug's own reported rates are listed below.

Foundayo
  • Nausea33%
  • Vomiting19%
  • Constipation18%
  • Diarrhoea15%

From ATTAIN-1

Xenical
  • Oily/fatty stools (steatorrhoea)27%
  • Faecal urgency22%
  • Oily spotting on underwear27%
  • Faecal incontinence8%
  • Abdominal pain/discomfort14%

From XENDOS

A rate is the share of trial participants who reported that reaction, not a prediction for any one person.

How they differ in practice

How you take it

  • Foundayo — Once-daily oral tablet. No food or water restrictions.
  • Xenical — Oral capsule 120 mg, three times daily with meals (prescription). Also available OTC as Alli at 60 mg.

Dose build-up

  • Foundayo — 3 mg → 6 mg → 12 mg → 36 mg, escalated over several months

Where a drug is not listed here, its prescribing information sets out its own dose steps.

How soon it acts

  • Foundayo — Appetite changes typically within the first 4 weeks; meaningful weight loss by 12–16 weeks
  • Xenical — Weight effects begin from the first week (related to calorie malabsorption), but significant loss takes 8–12 weeks

Heart and metabolic findings

  • Foundayo — Cardiovascular outcomes data pending.
  • Xenical — In the 4-year XENDOS trial, orlistat reduced progression from prediabetes to type 2 diabetes by 37% compared to placebo plus lifestyle changes.

As stated in each drug’s trial record — not a claim about which drug protects the heart more.

Other findings recorded

  • Foundayo — No food or water restrictions — take any time of day; available at $149/month self-pay (lowest dose) or $25/month with commercial insurance
  • Xenical — 37% reduction in progression to type 2 diabetes (XENDOS, 4 years); only approved obesity drug with a 4-year safety dataset

If you stop taking it

  • Foundayo — No withdrawal trial has been published for Foundayo.
  • Xenical — Weight is typically regained after stopping.

Common questions

Written and maintained by one person · Built with agentic AI tools · Every number checked against the cited trial · Not medical advice

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Every approved drug side by side, plus the other head-to-head pages
Foundayo in full
Foundayo — results, side effects, cost and how it is taken
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Xenical & Alli — results, side effects, cost and how it is taken
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Medical disclaimer: This website is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any treatment.