Semaglutide route of administration: injection, tablet, and what the evidence says

Why the same medicine needs two completely different doses depending on how it's given

The gap between 2.4mg (injection) and 25mg (tablet) surprises most people who encounter it. It's not a typo. Semaglutide taken orally faces a steep absorption challenge: the acidic stomach environment degrades peptide medicines quickly, and very little reaches the bloodstream without help. Novo Nordisk solved this by co-formulating the tablet with sodium N-(8-[2-hydroxybenzoyl] amino) caprylate (SNAC) an absorption enhancer that temporarily raises local stomach pH and helps semaglutide cross the gastric lining. Even so, oral bioavailability is roughly 1% of the dose, so the tablet delivers a much larger amount to compensate. The injection bypasses all of this: it deposits semaglutide into subcutaneous fat, where it absorbs steadily over several days. This pharmacokinetic difference is why the two formulations aren't interchangeable milligram-for-milligram. Patients established on the 2.4mg weekly injection who switch to the tablet move directly to the 25mg maintenance tablet, subject to clinical review, the prescriber makes that call based on the full picture, not a conversion formula. For practical detail on how to administer Wegovy, including the step-by-step process for the injection itself, the guide on this site covers everything you need to know.

What the phase-3 evidence actually shows for each route

The STEP 1 trial enrolled adults with obesity or overweight plus at least one weight-related condition, without diabetes, and found an average weight reduction of around 15% over 68 weeks at 2.4mg weekly semaglutide alongside lifestyle changes, a result that helped underpin the NICE recommendation for Wegovy (TA875). The oral route's primary evidence comes from the OASIS 4 phase-3 trial: 307 adults, 64 weeks, the same population profile. Average weight loss was around 13.6% versus roughly 2.4% with placebo regardless of adherence. Among participants who stayed fully on the programme, the figure rose to about 16.6%. That last number gets quoted often; the honest framing is that it describes a subgroup, not the average for everyone who started the trial. Both sets of results were achieved alongside a reduced-calorie diet and increased physical activity, the medicine works in context, not in isolation. If you're weighing these two routes against each other, it's worth reading the full semaglutide overview for the broader clinical picture.

Practical differences that actually matter day to day

The injection is given once a week, on any consistent day you choose. It needs refrigerating between 2°C and 8°C (check the patient information leaflet for the exact room-temperature window if you're travelling). A fresh needle is used each time. The abdomen, thigh and upper arm are all suitable sites; rotating prevents localised reactions. If injection technique is new to you, a short administration video can help before your first dose. The tablet, by contrast, needs no cold chain at all, a meaningful advantage if you travel frequently or your fridge situation is unpredictable. It does come with a firm timing rule: first thing in the morning, swallowed whole with a small amount of plain water (up to around 120ml), then a 30-minute wait before any food, coffee or other oral medicines. Miss that window and absorption drops sharply. One thing patients sometimes ask: if they're away over a bank holiday or their first pen arrives on a Friday, does the start date matter? The day itself is flexible, what counts is consistency week to week (for the injection) or the morning routine (for the tablet). Our prescribers at nume are available seven days a week to answer exactly this kind of question. For a closer look at choosing injection sites, and the wegovy administration instructions that cover each step of the process, this guide to Wegovy administration sites goes into the specifics.

Who each route is licensed for, and where the prescription conversation starts

Both formulations share the same broad eligibility threshold: adults with a BMI of 30 or above, or 27 or above alongside at least one weight-related condition such as high blood pressure, type 2 diabetes, dyslipidaemia or obstructive sleep apnoea. Lower BMI thresholds apply for some ethnic backgrounds under UK guidance. The injection (Wegovy) carries NICE backing under TA875, within specialist weight management services for NHS patients. The tablet was approved by the MHRA on 11 June 2026 and does not yet have a NICE appraisal, meaning it's available privately but not routinely on the NHS. Neither route is suitable during pregnancy, breastfeeding or when actively trying to conceive, and neither is licensed for under-18s. A history of pancreatitis or certain thyroid conditions requires particular care, the prescriber weighs these before recommending anything. The question of how semaglutide is administered is often the first one people ask; which form is appropriate comes down to the clinical conversation. You can explore the full range of weight-loss treatment options on our treatments page, where our prescribers can assess your situation properly.