Oral Semaglutide Weight-Loss Evidence: The OASIS Trials, Plainly
The question "does oral semaglutide work?" has a precise answer and a vague one, and most pages give the vague one. The precise answer is: a specific branded tablet, at a specific strength, tested in two trials, produced weight loss close to the injection. Whether that answer applies to the capsule a compounding pharmacy makes is a different question, and this page keeps the two apart.
The oral semaglutide page explains why the oral route is hard. This page is what happened when Novo Nordisk solved it.
OASIS 1: the proof of concept
OASIS 1 randomized 667 adults with overweight or obesity, without diabetes, to a high-strength oral semaglutide tablet or placebo for 68 weeks. Mean weight loss was 15.1% on the tablet against 2.4% on placebo. Around 85% of the semaglutide group lost at least 5% of their body weight, and more than a third lost 20% or more.
Those figures are, within the noise, the same as STEP 1 — the injectable semaglutide trial — at the same timepoint. The oral route, done properly, was not a weaker route.
The tablet in OASIS 1 was a strength far above the diabetes product Rybelsus, made with the same SNAC absorption enhancer, and taken under the same empty-stomach conditions. It was not a product anyone could buy.
OASIS 4: the product that was approved
OASIS 4 tested a lower-strength tablet than OASIS 1 — the one that became the approved Wegovy pill — in 307 adults over 64 weeks. Counting everyone regardless of whether they stayed on treatment, weight loss was 13.6% against 2.2% on placebo; among those who took it as prescribed, 16.6% against 2.7%. About a third of adherent participants lost a fifth of their body weight. Serious adverse events were less frequent on semaglutide than on placebo. Among participants with prediabetes, 71% returned to normal glucose against 33% on placebo.
That result is what the FDA approved on December 22 2025 — see the comparison page — and it is the evidence base for "an oral semaglutide that works for weight loss."
What the trials cannot tell you
Nothing about a compounded capsule. OASIS tested a SNAC-formulated tablet whose absorption had been characterized in years of pharmacokinetic work. A compounded capsule uses a different enhancer, or none, at a strength the prescriber chooses, with absorption that has never been measured. It may absorb well. It may absorb a fraction. The trial results describe the tablet, and they do not describe the capsule any more than a trial of a patch describes a cream.
Nothing about taking it wrong. The 13.6%-versus-16.6% gap in OASIS 4 is the adherence gap, and it is a reminder that the empty-stomach ritual is not a formality. Participants who did not keep to it lost less. Outside a trial, adherence is worse.
Nothing beyond 68 weeks. The injectable has SELECT and its three-year follow-ups; the tablet does not yet, though the same molecule at equivalent exposure is expected to behave the same way — the FDA carried the cardiovascular indication over on that reasoning.
How we use this
For a patient choosing the oral route, the approved tablet is the product the evidence describes, and where it is accessible it is the one we would reach for. Where a compounded capsule is prescribed, the conversation is explicit: the same molecule, a route the trials validated for a different formulation, and a result that will be less predictable. The main page says the same thing in its own words, and we would rather say it twice than have a patient learn it from the scale.
Frequently asked questions
The approved tablet does: 13.6% weight loss over 64 weeks in OASIS 4, 16.6% among those who took it as prescribed — close to the injection's results.
A 68-week trial of a high-strength oral semaglutide tablet in 667 adults: 15.1% weight loss against 2.4% on placebo, essentially matching the injectable STEP 1 trial.
In the trials of the branded tablet, yes, within a few percentage points. Adherence to the empty-stomach routine is what makes the difference in practice.
No. The trials tested a specific SNAC-formulated tablet. A compounded capsule has a different, untested absorption profile.
Because absorption depends on the empty-stomach ritual. In OASIS 4, the gap between everyone and those who followed it was three percentage points of body weight.
Not its own trial yet. The FDA extended the injectable's cardiovascular indication to the tablet on the basis of equivalent exposure to the same molecule.
Where this fits in your plan
The Semaglutide Oral Capsules page covers how the oral route is used here; the comparison page covers which oral product. A baseline panel comes first.
We measure first. Then we act.
References
- Knop FK et al. Oral semaglutide taken once per day in adults with overweight or obesity (OASIS 1): a randomized, double-blind, placebo-controlled, phase 3 trial. The Lancet 2023;402:705–719. [title abridged]
- OASIS 4: oral semaglutide in adults with overweight or obesity — phase 3 results. NEJM 2025.
- Novo Nordisk. Wegovy pill FDA approval — company announcement, December 22 2025.
- Wilding JPH et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). NEJM 2021;384:989–1002.
- Buckley ST et al. Transcellular stomach absorption of a derivatized glucagon-like peptide-1 receptor agonist. Science Translational Medicine 2018;10:eaar7047 — the SNAC mechanism.
- Back toSemaglutide Oral Capsules
- Compounded oral semaglutide vs Rybelsus and the Wegovy pillThree oral semaglutides now exist and only two have trials. How the Wegovy pill, Rybelsus and a compounded capsule differ in absorption, evidence and what they are for.Read
- Semaglutide and heart riskThe one weight-loss drug with a finished cardiovascular outcomes trial in people without diabetes. Who was in SELECT, what it found, and what it means if your ApoB is high.Read
- Oral tirzepatide vs orforglipronOne is an approved pill with a 72-week trial and no food rules. The other is a compounded capsule of a stronger molecule with no trial at all. How to think about the choice.Read
How we write and review our content
ACT 2 Health provides clinician-led care. Treatments are available only to eligible patients following clinical evaluation and within applicable regulations. This content is educational and is not medical advice. Individual results vary.
All medical decisions are made solely by licensed healthcare professionals. Medications are prescribed only when medically necessary. GLP-1 medications are not suitable for everyone. Results may vary.
Compounded medication. Prepared by a licensed compounding pharmacy under a prescription written for you. Compounded medications are not FDA-approved, are not reviewed by the FDA for safety or effectiveness, and are not equivalent to or interchangeable with any branded product. Prescribed only when a licensed provider determines it is medically appropriate.
Care is delivered via telemedicine by healthcare professionals licensed in the state where the patient is located. Services are available only in states where our providers are licensed.