Semaglutide weekly: how the once-a-week injection schedule works

Why is semaglutide taken weekly rather than daily?

The answer lies in how semaglutide is engineered. The molecule has a long half-life, achieved by attaching it to a fatty-acid chain that binds to albumin in the blood. This binding slows its clearance, keeping active drug levels stable for a full seven days from a single injection. That pharmacokinetic design is deliberate: it means no daily pill routine, no twice-weekly scheduling, just one injection per week.

For practical purposes this matters quite a bit. You pick a day that suits your routine (a Monday morning before work, a Sunday evening) and it stays the same each week. The NHS guidance on weight-management injections notes that consistency on the same day helps maintain steady drug levels. If you want to understand more about what that rhythm looks and feels like in practice, our page on Wegovy once-weekly dosing covers the routine in detail.

It is also worth being clear that semaglutide is a GLP-1 receptor agonist, acting on receptors in the brain and gut to reduce hunger signals and slow the rate at which the stomach empties. If you have ever wondered whether Wegovy is a weekly treatment, the short answer is yes, the once-weekly injection delivers a sustained effect across all seven days, it is not a drug you feel sharply for a few hours and then feel nothing.

How does the weekly dose build up from the starting point?

Treatment does not begin at the full maintenance dose. The licensed UK pathway starts at 0.25mg weekly for four weeks, then steps up to 0.5mg, then 1.0mg, 1.7mg, and finally 2.4mg, each step approximately four weeks apart. The 7.2mg dose, approved by the MHRA in April 2026, represents a further stage for those who need it, reached after establishing tolerance at lower doses. Your prescribing clinician decides the pace.

The step-up structure exists for a straightforward reason: gastrointestinal side effects (nausea, stomach upset, loose stools) are most common when starting or increasing a GLP-1 medicine. A slower escalation gives your system time to adapt. The STEP 1 trial, which tested semaglutide 2.4mg over 68 weeks in adults with obesity, reported an average weight reduction of around 15%, a figure that applies to people who reached and sustained the maintenance dose, published in the New England Journal of Medicine.

One thing our prescribers hear regularly: people sometimes assume the early doses are doing nothing because the number on the scale hasn't shifted yet. The starter doses are there to settle your system, not to deliver the therapeutic effect straight away. Patience with the schedule pays off.

Who is the weekly semaglutide injection licensed for in the UK?

In the UK, Wegovy is licensed for adults with a BMI of 30 or above, or a BMI of 27 or above alongside at least one weight-related condition such as high blood pressure, high cholesterol, type 2 diabetes or obstructive sleep apnoea. Lower BMI thresholds apply for some ethnic backgrounds under UK clinical guidance, a point worth raising during any consultation.

It is not recommended during pregnancy, breastfeeding or for anyone trying to conceive. It is not licensed for under-18s. Certain medical histories (including a personal or family history of medullary thyroid carcinoma) require a careful prescriber conversation before starting. For a full look at eligibility criteria and what a private consultation covers, the semaglutide overview page sets this out in depth.

NICE has also published guidance on semaglutide (TA875) within specialist NHS weight management services, but NICE criteria and private licence eligibility are different things, and your prescriber assesses the full picture. Worth reading: NICE technology appraisal TA875 explains the NHS recommendation for semaglutide and the conditions attached to it.

If you are considering the cost side of treatment as part of your decision, our Wegovy cost page breaks down what private treatment typically involves financially.

What should you know about the weekly injection in practice?

The pen itself is pre-filled and pre-set at each dose. You inject into fatty tissue (the abdomen, thigh or upper arm) rotating the site each week to avoid irritation. Each pen contains four doses, so one pen lasts a month. When your treatment arrives from a GPhC-registered pharmacy, it comes in plain, unbranded packaging via DPD with tracked delivery, refrigerated for transit, the pen goes straight into your fridge door when you get home.

Storage is refrigerated at 2–8°C; the Patient Information Leaflet specifies the limited window during which a pen can be kept at room temperature, so always read it rather than guessing. Our guide on how Wegovy is taken weekly, including what to expect from the injection schedule, covers what to know before you go alongside our dedicated page on taking Wegovy on a flight.

Missed doses and what to do if you are late on a given week are covered in the Patient Information Leaflet; your prescriber is also the right person to ask, not forums. If you have questions about the process at our pharmacy, the FAQs page covers common queries, or you can contact the team directly.

If weekly semaglutide sounds like something worth exploring properly, speak to our prescribers, a free consultation is reviewed the same day by a GPhC-registered clinician, with no algorithm making the call.