Wegovy (semaglutide)

Wegovy is semaglutide licensed for weight management. Same molecule as Ozempic®, different label, higher ceiling, and a different pen: each Wegovy pen holds a single dose and is discarded after use.

How it works

It acts on the GLP-1 receptor, the same target as the natural gut hormone it is engineered to imitate. Activating that receptor does three things at once: it amplifies insulin release when blood glucose is high, it slows the rate at which the stomach empties, and it changes appetite signalling in the brain.

Those three actions explain almost everything about the experience of taking it. The metabolic benefit comes from the first; the sense of eating less without deciding to comes from the third; and most of the side effects are the second one felt from the inside. The mechanism in full is here.

What sets it apart

The full escalation takes about sixteen weeks, which is longer than most people expect and is the single most common source of early disappointment. The starting dose is not a treatment dose; it exists so your gut can adapt. Judging the medicine at week three is judging it before it has started.

Who it is for

Wegovy is licensed for chronic weight management; cardiovascular risk reduction in some populations. That licence is not a formality: it determines what your prescriber can lawfully prescribe it for, what a health system or insurer will fund, and which dose ceiling applies. Two products containing the same molecule can carry different licences, and that is usually the real difference between them.

Whether it suits you is a separate question, and one that depends on your medical history rather than on the product. The exclusions that come up most often are a personal or family history of medullary thyroid carcinoma or MEN 2, a history of pancreatitis, pregnancy or planned pregnancy, and severe gastrointestinal disease. None of these can be assessed from a web page — they are the reason the first conversation happens with a clinician.

The dose ladder

Treatment starts below a working dose and climbs on a schedule. The starting dose is not a treatment dose — it exists so the gut can adapt.

Maintenance: 2.4 mg weekly. If that is not tolerated, a prescriber may hold at 1.7 mg. The full schedule, with what each rung is for, is here.

What the first months look like

Wegovy reaches a stable blood level in 4–5 weeks, which is why the early weeks so often feel like nothing is happening. They are not a failure of the medicine; they are the medicine still arriving.

• Month one. Blood levels climbing toward their plateau on a starting dose that is not expected to do much. Side effects, if they appear, cluster in the days after each increase.
• Months two and three. The first genuinely therapeutic doses. This is usually where appetite change becomes unmistakable rather than ambiguous.
• Beyond. Either continued escalation or settling at a dose that works. Both are legitimate destinations; the top of the ladder is a ceiling, not a target.

Side effects, in outline

Because Wegovy climbs to a higher dose than Ozempic®, the later steps are where most people meet their tolerance limit. Holding at 1.7 mg is a recognised maintenance strategy, not a failure — a dose you stay on beats a dose you abandon. The common effects — nausea, early fullness, constipation, reflux and fatigue — trace back to a stomach emptying more slowly, and they follow the dose ladder rather than appearing at random. The full picture, including the symptoms that are not side effects to wait out, is here.

Taking it

Once weekly, any day, with or without food. Single-dose pen, one per week. Available strengths: 0.25 mg, 0.5 mg, 1 mg, 1.7 mg and 2.4 mg pens.

Because it is taken weekly, the routine that matters most is consistency — a fixed time you can keep to, and a way of recording that you did. The step-by-step routine is here, and the rule for a late dose is here.

Storage, in brief

Unopened: 2–8 °C. Once in use: 28 days (US label) or up to 6 weeks (EU label) at 8–30 °C. Two clocks run — the printed expiry on an unopened product, and the in-use window that starts at first use and does not reset if the product goes back in the fridge. The detail, including travel, is here.

Stopping

Because Wegovy clears over 4–5 weeks rather than overnight, stopping is a gradual process whether or not you intend it to be. Appetite returns along that curve, which most people describe as something that crept up over weeks rather than an event.

That slow return is worth planning for. The window in which appetite is coming back but is not yet fully back is the window in which habits either hold or do not — and it is a much better time to have a plan than to improvise one. Stopping is also a decision to make with your prescriber rather than unilaterally, particularly where the medicine is treating diabetes rather than weight.

What it does not do

• It does not burn fat. There is no metabolic furnace being switched on. Weight changes because intake falls.
• It does not choose what you lose. Weight lost quickly, on low protein and without resistance training, includes a meaningful share of lean tissue. This is the most consequential under-discussed part of the treatment.
• It does not permanently retrain appetite. The effect is a response to a signal, and the signal stops when the medicine does.

How it compares

• Ozempic vs Wegovy — Same molecule, different label and ceiling.
• Wegovy vs Zepbound — The two weight-management flagships.
• Saxenda vs Wegovy — Daily against weekly, and an older molecule against a newer one.

Wegovy in detail

Common questions about Wegovy

How long does it take to get to the full Wegovy dose?

About sixteen weeks — five doses, four weeks each. This is longer than most people expect and is the most common source of early disappointment. The 0.25 mg starting dose is not a treatment dose; it exists so your gut can adapt.

Which Wegovy dose causes the most side effects?

Usually the later steps — 1.7 mg and 2.4 mg — because they are where most people meet their tolerance limit. The first increase, from 0.25 to 0.5 mg, is also commonly reported as a noticeable jump because it is the first dose doing real work.

I missed a whole week of Wegovy. Do I restart the ladder?

One missed week generally needs no adjustment — take the next dose on your usual day at the same strength. Several consecutive missed weeks is different: levels and tolerance have both fallen, and resuming at your previous dose can reproduce a first escalation at full strength. That is a conversation before restarting.

How long can a Wegovy pen stay out of the fridge?

This is the clearest case of regional divergence in the class: the US and EU labels state different in-use periods for the same product. Use the figure on the leaflet in your box, not one quoted online.

Do I need to prime a Wegovy pen?

No. Each pen holds a single dose and is used once, so there is no priming step and no needle to attach or change. Follow the instructions supplied with your pen — devices differ between regions.