Saxenda (liraglutide)

Saxenda is liraglutide, a daily injection for weight management and the oldest product in this class still in wide use. Its short half-life — about 13 hours against semaglutide’s week — changes almost everything about how it behaves.

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

A daily injection means levels rise and fall within each day rather than plateauing across a week. The escalation is correspondingly faster: one step per week rather than one per month, reaching maintenance in five weeks instead of sixteen.

Who it is for

Saxenda is licensed for chronic weight management. 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: 3 mg daily. The full schedule, with what each rung is for, is here.

What the first months look like

Saxenda reaches a stable blood level in about 3 days, 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

The same gastrointestinal profile, arriving faster because the ladder moves weekly. The compressed schedule is why some people find the first month of Saxenda harder than the first month of a weekly product. 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 daily, at any time, with or without food. Multi-dose pen. Available strengths: 0.6, 1.2, 1.8, 2.4 and 3 mg per dose.

Because it is taken daily, 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: 30 days at up to 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 Saxenda clears over about 3 days 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

• Saxenda vs Wegovy — Daily against weekly, and an older molecule against a newer one.
• Saxenda vs Victoza — The same molecule under two labels.

Saxenda in detail

Common questions about Saxenda

Why does Saxenda go up every week instead of every month?

Because liraglutide clears far faster. Its half-life is about 13 hours against semaglutide's week, so a new dose reaches a stable level in about three days rather than a month. The ladder can move weekly because the pharmacology allows it.

Is the first month of Saxenda harder than a weekly injection?

Often, yes — not because the drug is harsher but because the schedule is compressed. Four increases in four weeks means four waves in a month, where a weekly product spreads the same number over four months.

I missed one day of Saxenda. Do I take two tomorrow?

No. Skip the missed dose entirely and take the next one at your usual time. Never take an extra dose to compensate.

How long does a Saxenda pen last once opened?

Thirty days from first use, after which it is discarded even if medicine remains in it. With a daily injection this is usually close to when the pen empties anyway.

Does the time of day matter for Saxenda?

More than it does for weekly products. Because levels rise and fall within a day, keeping roughly to the same time keeps them even. Choose a time you can actually keep to every day rather than an ideal one.