The starter dose for semaglutide: what it does, and how to think about it

Why the starter dose exists, and why skipping it would backfire

Semaglutide slows gastric emptying and acts on GLP-1 receptors in the brain to reduce appetite. Both effects are dose-dependent, which means the higher the dose, the more pronounced they become. That is precisely why introducing the drug gradually matters: starting at a low dose gives the gastrointestinal tract time to adapt before the full therapeutic load arrives.

The most common early side effects (nausea, loose stools, indigestion) are not random. They follow directly from this mechanism, and they are most intense after a step up. Starting at 0.25mg rather than jumping to a higher level substantially reduces that early burden for most people. The Wegovy starter dose guidance reflects a titration schedule designed specifically around this tolerability logic, not around speed.

A question our prescribers hear fairly often is whether someone who previously tolerated a GLP-1 medicine well can skip the starter phase. The answer is always a clinical one, made case by case, previous history matters, but so does how long someone has been off treatment. That conversation belongs with your prescriber, not with a general guide.

What the titration schedule looks like from here

After four weeks at 0.25mg, the standard Wegovy schedule moves to 0.5mg, then 1.0mg, then 1.7mg, and finally 2.4mg, each step held for roughly a month. The clinical reasoning behind each starting point stays the same throughout: slow enough to tolerate, fast enough to make progress.

Since January 2026, a 7.2mg maintenance option has also been available in the UK following MHRA approval, with a dedicated single-dose pen approved in April 2026. That higher ceiling is not relevant to the starting phase, but it does change how people think about the ceiling of treatment. The titration to reach 7.2mg still begins at 0.25mg; nothing about the end-point changes the beginning.

The full breakdown of Wegovy dose steps sets out what each level is designed to achieve. Worth reading before you start, so the gradual climb makes sense rather than feeling like a delay.

Deciding whether Wegovy is clinically appropriate for you at all

Before the starter dose question even becomes relevant, there is a prior question: is semaglutide the right treatment for this person? The licensed criteria for Wegovy in the UK cover adults with a BMI of 30 or above, or 27 to 29.9 alongside at least one weight-related condition such as high blood pressure, which Wegovy can itself affect in ways worth understanding before you start, obstructive sleep apnoea or type 2 diabetes. Lower BMI thresholds apply for some ethnic backgrounds under UK guidance. But the licence is a floor, not a ceiling, a prescriber still considers the whole picture, including other medicines, medical history, and whether the goals are realistic.

Semaglutide is a prescription-only medicine and must be assessed and prescribed by a qualified clinician. The STEP 1 trial, published in the New England Journal of Medicine, found an average body-weight reduction of around 15% over 68 weeks at the 2.4mg maintenance dose, a figure that reflects months of titration, not days at 0.25mg.

The eligibility considerations for starting semaglutide for weight loss are worth understanding before booking a consultation, so you arrive with realistic expectations. If you'd like to understand the broader landscape first, the weight-loss treatment overview covers how GLP-1 medicines fit alongside other options.

Practical life with the starter dose

The pen needs to be stored in the fridge, most people keep it in the fridge door, which is convenient as long as the temperature doesn't fluctuate too much when the door opens frequently. For exact storage windows and what to do if a pen has been out of the fridge, the Patient Information Leaflet that comes with your medicine is the definitive source; the NHS semaglutide page also summarises the key practical points in plain language.

Injections are given once a week, on the same day each week if possible, into the abdomen, thigh, or upper arm, rotating sites each time. The starter-dose pen feels identical to every subsequent pen, the difference is only in the medicine cartridge, not the device. Some people feel almost nothing at 0.25mg in terms of appetite change; that is expected and not a sign it isn't working. The adjustment is happening even when it isn't perceptible.

Nausea, when it does appear, tends to peak in the first few days after an injection and then ease. Eating smaller meals, avoiding very rich or fatty foods, and staying well hydrated all help. If side effects feel unmanageable at any point, the prescriber is the right first call, not a decision to simply stop. That conversation is part of what aftercare is for.