Is aleniglipron better than orforglipron?

Its Phase 2 figures are higher, but the comparison is indirect — different trials, durations and populations, and orforglipron has Phase 3 data and an approval while aleniglipron has neither.

Why do sources quote 12.1% and others 16.3%?

Two different trials. 12.1% is ACCESS at 36 weeks on 120 mg, absolute. 16.3% is ACCESS II at 44 weeks on 180 mg, placebo-adjusted.

Is aleniglipron available anywhere?

No. It has completed Phase 2 and holds no marketing authorisation in any jurisdiction.

GLP-1 & Incretin Science

What Is Aleniglipron? The Second Oral Small-Molecule GLP-1

JMWritten & reviewed by Jack Muncaster · Founder, UK PeptidesLast reviewed 2026-08-233 cited sources

Aleniglipron is a once-daily oral non-peptide GLP-1 receptor agonist developed by Structure Therapeutics. Its Phase 2b ACCESS trial, published in Nature Medicine on 10 August 2026, reported 12.1% mean weight reduction at 36 weeks on 120 mg. The separate ACCESS II trial reported 15.3% absolute reduction at 44 weeks on 180 mg.

Key facts

Class: Oral non-peptide GLP-1 receptor agonist
Developer: Structure Therapeutics
Administration: Once daily, oral
ACCESS (Phase 2b): 230 adults, 36 weeks, 38 US centres
ACCESS 120 mg result: −12.1% absolute vs −0.5% placebo
ACCESS II: 85 adults, 44 weeks
ACCESS II 180 mg: −15.3% absolute, −16.3% placebo-adjusted
Status: Phase 2 complete; not authorised anywhere

Why it matters that this is the second one

Orforglipron established that a small molecule could activate the GLP-1 receptor well enough to be a licensed medicine. Aleniglipron is the compound that questions the assumption which followed — that the oral route necessarily costs you effect size. Orforglipron reported 11.2% at 72 weeks on its highest dose. Aleniglipron's ACCESS II reported 15.3% absolute at 44 weeks on 180 mg, in a shorter trial, with the reduction curve still descending at the end.

The two trials, and why they report different numbers

ACCESS is the larger Phase 2b: 230 adults across 38 US medical centres over 36 weeks, published in Nature Medicine on 10 August 2026. Its 120 mg arm reported 12.1% absolute reduction against 0.5% on placebo. ACCESS II is a smaller, longer study — 85 adults over 44 weeks — testing 120 mg, 180 mg and 240 mg. Both are correct; they are different trials with different sizes, durations and dose ranges, and coverage routinely quotes one figure without saying which trial produced it.

A case where placebo-adjusted exceeds absolute

ACCESS II reported 15.3% absolute and 16.3% placebo-adjusted for the 180 mg arm. Placebo-adjusted is the larger of the two, which surprises people who assume adjustment always shrinks a number. The reason is that the placebo arm gained 1.1%, so subtracting it adds to the difference. Compare ACCESS, where placebo lost 0.5% and adjustment would reduce the figure. Whether placebo-adjusted is bigger or smaller than absolute depends entirely on which direction the placebo arm moved.

The dose-response is not monotonic

ACCESS II reported 13.6% at 120 mg, 15.3% at 180 mg and 15.0% at 240 mg on the absolute measure. The highest dose did not produce the largest reduction. With 85 participants split across four arms this is well within the noise a small trial produces, but it is the kind of detail that matters for Phase 3 dose selection and it is not what a clean dose-response curve looks like.

Tolerability and the safety database

Adverse events were primarily gastrointestinal, with nausea and vomiting most common during titration — the class pattern. Discontinuation due to adverse events was reported at 3.7% across active arms at 120 mg or higher between weeks 28 and 44. Across a database of more than 625 participants, Structure Therapeutics reported no drug-induced liver injury, no persistent liver-enzyme elevations and no QTc prolongation.

What is still unknown

These are Phase 2 results, and ACCESS II in particular is small. No Phase 3 data exist, the compound holds no authorisation anywhere, and the absence of a plateau at 44 weeks means the eventual effect size is genuinely unknown rather than merely unreported. An open-label extension reported 16.2% at 56 weeks on 120 mg, which is consistent with the curve continuing.

Quick reference

Trial	n	Duration	Dose	Absolute	Placebo-adjusted
ACCESS	230	36 wks	120 mg	−12.1%	—
ACCESS II	85	44 wks	120 mg	−13.6%	−14.7%
ACCESS II	85	44 wks	180 mg	−15.3%	−16.3%
ACCESS II	85	44 wks	240 mg	−15.0%	−16.0%
ACCESS OLE	—	56 wks	120 mg	−16.2%	—

Extended research context

The GLP-1 & Incretin Science deep dive

Deep dive: the two routes to a bigger effect

Every compound trying to beat GLP-1 alone has taken one of two routes. The first adds more receptors from the same hormone family — GIP in tirzepatide, GIP and glucagon in retatrutide. The second adds a non-incretin satiety hormone, which in practice means amylin: CagriSema combines cagrilintide with semaglutide, and amycretin engages both receptors from one molecule. Both routes work, because they recruit signalling pathways that do not fully overlap. Neither has escaped the constraint that binds all of them, which is that gastrointestinal tolerability worsens as effect size grows.

Deep dive: why a percentage is not a result

The most-quoted numbers in this field are the least comparable. REDEFINE 1 reported 22.7% and 20.4% for the same compound in the same trial — the first among participants who adhered to treatment, the second across everyone randomised. TRIUMPH-1 reported 28.3% in an uncomplicated obesity population while TRIUMPH-3 reported up to 22.6% in adults with established cardiovascular disease, using the same compound. Before any two figures can be compared they have to match on estimand, population, duration, comparator and whether the number is placebo-adjusted. Most published comparisons match on none of them.

Deep dive: what happens after the trial stops

Every headline figure describes weight while treatment continues. The STEP-1 extension found that a year after semaglutide was stopped, participants had given back roughly two-thirds of what they lost, moving from 17.3% mean reduction to a net 5.6% — though average weight remained below baseline and nearly half stayed at least 5% down. Meta-analysis puts regain at around 0.8 kg per month. This is why maintenance studies such as TRIUMPH-6 matter more to the field's future than another two points of peak reduction.

Research applications

▸Comparing incretin and amylin compounds on a like-for-like basis
▸Interpreting estimands, thresholds and placebo-adjusted figures in trial reports
▸Tracking the obesity pipeline across sponsors and jurisdictions
▸Understanding receptor pharmacology behind GLP-1, GIP, glucagon and amylin
▸Distinguishing licensed medicines from investigational compounds

Handling checklist

✓Identify which estimand a quoted percentage comes from before citing it
✓Check the trial population and baseline BMI against the comparison you are making
✓Confirm the duration and whether the reduction curve had plateaued
✓Read discontinuation rates alongside efficacy figures
✓Verify every NCT identifier against ClinicalTrials.gov rather than secondary reporting

Common research-handling mistakes

Learnt from thousands of researcher orders across our UK labs.

✗ Comparing headline percentages across different trials

Fix: Population, duration, estimand and comparator all differ; the numbers are not interchangeable.

✗ Quoting the larger of two figures from the same trial

Fix: Name the estimand. Efficacy and treatment-policy answer different questions.

✗ Treating peak reduction as a durable outcome

Fix: Substantial regain follows cessation across the class; peak figures describe a maintained state.

✗ Assuming an oral route means a weaker mechanism

Fix: Route and receptor count are independent. Orforglipron is weaker because it hits one receptor, not because it is a tablet.

✗ Reading investigational compounds as available treatments

Fix: Most of this pipeline holds no authorisation anywhere; mazdutide is approved only in China.

Continue researching

Peer-reviewed guides, comparators and matched reference materials.

Frequently asked questions

Is aleniglipron better than orforglipron?: Its Phase 2 figures are higher, but the comparison is indirect — different trials, durations and populations, and orforglipron has Phase 3 data and an approval while aleniglipron has neither.
Why do sources quote 12.1% and others 16.3%?: Two different trials. 12.1% is ACCESS at 36 weeks on 120 mg, absolute. 16.3% is ACCESS II at 44 weeks on 180 mg, placebo-adjusted.
Is aleniglipron available anywhere?: No. It has completed Phase 2 and holds no marketing authorisation in any jurisdiction.

Primary sources & clinical trials

Peer-reviewed research and registered trials from PubMed, ClinicalTrials.gov, PubChem, FDA and NIH. All links open in a new tab and point to the primary source, so every claim can be verified at origin.

Written and reviewed by

Jack Muncaster · Founder, UK Peptides

Jack founded UK Peptides in Manchester after repeatedly receiving research compounds with missing or recycled paperwork. He is responsible for supplier selection, batch release decisions and the content published in this research library. Every article here is sourced to primary literature and every product page to a signed third-party certificate.

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