Has anyone compared Wegovy and Xenical in the same trial?

No head-to-head trial has compared these two drugs. Wegovy's figures come from STEP 1 (68 weeks) and Xenical's from Sjostrom 1-year RCT (52 weeks), which enrolled different people for different lengths of time. Numbers from separate trials can be read side by side, but they are not a measured difference.

What does each one cost per month?

Wegovy is listed at $349–$399/month (with the manufacturer savings programme; list price ~$1,349). Xenical is listed at $40–$400/month (over-the-counter strength; prescription runs to $400). The full price note for each is set out in the cost section above. What you pay depends on your insurance, your dose and your pharmacy.

Can I switch from Wegovy to Xenical?

Switching between weight-loss medicines is a decision for the prescriber who knows your history, your other medicines and how you have responded so far — this site cannot make it for you. What switching involves in practice, including dose steps and the gap between drugs, is set out on the switching page.

Which side effects were reported most often?

In STEP 1 (68 weeks), the reaction reported most often with semaglutide was nausea — 44% of participants. In XENDOS (208 weeks), the reaction reported most often with orlistat was oily/fatty stools (steatorrhoea) — 27% of participants. Rates come from different trials with different participants, and a rate is not a prediction for any one person.

Wegovy vs Xenical: trials compared

At a glance

Wegovy and Xenical compared on form, trial results, cost and reported side effects
Attribute	Wegovy	Xenical
Form	Weekly injection	3x daily with meals
How often	Injection: once-weekly	Three capsules daily, taken with each fat-containing meal
Weight loss in trials	Up to 14.9% — STEP 1 (68 weeks)	Up to 8.5% — Sjostrom 1-year RCT (52 weeks)
FDA approved	2021	1999
Made by	Novo Nordisk	Roche (Xenical) / GSK (Alli OTC)
How it works	A GLP-1 analogue with an extended half-life of approximately one week.	Blocks pancreatic lipase enzymes in the small intestine, preventing approximately 30% of dietary fat from being broken down and absorbed.
Monthly cost, self-pay	$349–$399/mowith the manufacturer savings programme; list price ~$1,349	$40–$400/moover-the-counter strength; prescription runs to $400
Most reported reaction	Nausea 44% (STEP 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.

Wegovy(semaglutide)14.9%

STEP 1 (68 weeks)

Xenical(orlistat)8.5%

Sjostrom 1-year RCT (52 weeks)

In clinical trials, participants taking semaglutide lost on average up to 14.9% of their starting body weight, and participants taking orlistat lost on average up to 8.5%. Those numbers come from two different studies: STEP 1 enrolled 1,961 adults with obesity or overweight with comorbidities, no type 2 diabetes over 68 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.

Wegovy$349–$399/mo

with the manufacturer savings programme; list price ~$1,349

Self-pay via NovoCare Pharmacy: $349/month for the 0.25–2.4 mg pens, $399/month for the Wegovy HD 7.2 mg pen. New patients pay a $199/month introductory price for the first two months on the 0.25 mg or 0.5 mg starting doses (offer runs through December 31, 2026, then the regular price applies). ~$25/month with eligible commercial insurance, capped at $100/month in savings. List price ~$1,349/month. The Wegovy pill is priced separately (see the oral pill entry). Per wegovy.com and novocare.com on 17 September 2026.

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. Wegovy: $349–$399/month. Xenical: $40–$400/month. Insurance, dose and pharmacy all change both figures.

Side effects reported in the trials

STEP 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.

Wegovy

Nausea44%
Diarrhoea30%
Vomiting24%
Constipation24%

From STEP 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

Wegovy — Two forms: once-weekly injection (2.4 mg) OR once-daily pill (25 mg). Same drug, similar results, very different cost and convenience.
Xenical — Oral capsule 120 mg, three times daily with meals (prescription). Also available OTC as Alli at 60 mg.

How soon it acts

Wegovy — Noticeable effects within 4–8 weeks; maximum weight loss typically reached by 60–68 weeks
Xenical — Weight effects begin from the first week (related to calorie malabsorption), but significant loss takes 8–12 weeks

Heart and metabolic findings

Wegovy — The SELECT trial (n=17,604) showed a 20% reduction in major adverse cardiovascular events against placebo.
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

Wegovy — 20% reduction in heart attacks and strokes (SELECT trial, established CVD); improved blood pressure and cholesterol across STEP trials
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

Wegovy — In STEP 4, stopping semaglutide after a 20-week run-in led to significant weight regain.
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

How this site is built →

Next step most people take

Compare all optionsEvery approved drug side by side, plus the other head-to-head pages Wegovy in fullWegovy & Ozempic — results, side effects, cost and how it is taken Xenical in fullXenical & Alli — results, side effects, cost and how it is taken Take the option finder quizAnswer a few questions and see which options fit your situation

Built with agentic AI tools and not a substitute for medical advice

Last reviewed: September 2026

Was this page helpful?

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. Prices shown are United States self-pay or list prices and vary by insurance and country.