Oral semaglutide (Rybelsus, Ozempic tablets, Wegovy tablets): the peptide that survives the stomach

Peptides are digested. Oral semaglutide gets around that by being co-formulated with an absorption enhancer, salcaprozate sodium (SNAC), which lets a small fraction of the dose cross the stomach lining before digestive enzymes reach it. That is why the label is so specific about how the tablet is taken, and why the milligram numbers on the three tablets bear no simple relationship to the injection doses on the semaglutide injection entry.

Mechanism and receptor profile

Identical to injected semaglutide: a GLP-1 receptor agonist with no GIP or glucagon activity. The difference is entirely in delivery. Because absorption is low and variable, the tablet doses are far larger than the weekly injection doses (25 mg a day of tablet against 2.4 mg a week of injection) and the label makes the 30-minute fasting window a condition of use rather than advice.

The three tablets and their approvals

The current Rybelsus label covers both tablet sets and states in its first line that Rybelsus and Ozempic tablets are not substitutable on a milligram-to-milligram basis. Wegovy tablets share the 1.5, 4 and 9 mg escalation strengths but are approved under their own application for different indications.

Dosing as the labels state it

Take one tablet once daily on an empty stomach in the morning with up to 4 ounces of plain water, swallow whole, then wait at least 30 minutes before food, drink or other oral medicines.

For Wegovy tablets the label adds: if 25 mg is not tolerated, consider switching to the 1.7 mg weekly injection; a patient on the 2.4 mg injection may start 25 mg tablets one week after the last injection; a patient on 25 mg tablets may start the 2.4 mg injection the day after the last tablet.

Pivotal trials and their numbers

The Wegovy label reports OASIS 4 as Study 7 with slightly different imputation: minus 13.6% against minus 2.4%, difference minus 11.2 points (95% CI minus 13.6 to minus 8.8). The 25 mg result sits between the 2.4 mg injection (STEP 1, minus 14.9%) and the older 3 mg liraglutide injection (SCALE, about minus 8%), which is a useful mental anchor as long as you remember these are three different trials.

Adverse reactions from the label

For the 25 mg Wegovy tablet the label reports that 6.9% of patients discontinued for adverse reactions against 5.9% on placebo, that gastrointestinal reactions were the most common reason (3.4% against 2%), and that the types and frequencies of common adverse reactions were similar to the injection's Table 3 (nausea 44%, diarrhea 30%, vomiting 24%, constipation 24% on 2.4 mg weekly). It does not publish a separate rate table for the tablet.

Boxed warning

All three tablets carry the thyroid C-cell tumor boxed warning and the contraindication for personal or family history of medullary thyroid carcinoma or MEN 2. The Rybelsus label's warning list matches Ozempic's: pancreatitis, retinopathy complications, hypoglycemia with insulin or secretagogues, acute kidney injury, severe gastrointestinal reactions, hypersensitivity, gallbladder disease, and aspiration under anaesthesia.

Status and manufacturer

Approved and marketed by Novo Nordisk. No compounded oral semaglutide is FDA approved; the absorption enhancer and the tablet manufacturing are what make the oral route work, and a pharmacy-made capsule or sublingual product has no label and no trial behind it.

Where next

The other oral GLP-1, the small molecule orforglipron (Foundayo), takes a different route to the same receptor and has no food or water restriction. Compare the two in the agent comparison table. Injection dosing, including the new 7.2 mg dose, is on the semaglutide injection entry.