Starting Wegovy for the First Time: the Decision and What Comes Next

How the gradual dose schedule actually works for you

The starting dose of 0.25mg is not the dose that drives weight loss. Its job is to let your body adjust to semaglutide before the medicine reaches its working range. The titration schedule (0.25mg, then 0.5mg, then 1.0mg, then 1.7mg, then 2.4mg, each step roughly four weeks apart) is set by your prescriber and exists because pushing too quickly is the main reason people experience persistent nausea. Moving through it steadily makes the process more manageable.

You can read more about what the opening days specifically involve on our guide to your first day on Wegovy, which covers what to prepare before your pen arrives and what to expect hour by hour. The pace of titration is always a clinical decision; if a step feels difficult, your prescriber can slow things down. That conversation matters more than sticking to a rigid calendar.

The semaglutide overview page explains how the medicine works at a biological level, including the GLP-1 receptor mechanism that slows gastric emptying and signals fullness to the brain. Understanding the mechanism can help the slower start feel more purposeful rather than frustrating.

Side effects to recognise, and what actually warrants concern

Nausea is the side effect most people encounter in the first few weeks. For many, it is mild and settles within days of each new dose. Vomiting, diarrhoea, constipation, indigestion and low appetite are also commonly reported, particularly close to injection day. Eating smaller portions, avoiding fatty or rich food, and staying well hydrated tend to help. These are not signs that the medicine is not working — they are signs that the adjustment is under way.

Some symptoms do need prompt attention. Severe stomach pain that persists and radiates toward the back, with or without vomiting, should be assessed medically straight away, this can indicate pancreatitis, which the MHRA highlighted in a January 2026 Drug Safety Update as an infrequent but serious risk with GLP-1 medicines. Signs of a serious allergic reaction, sudden changes in vision, or symptoms of gallbladder problems also warrant urgent review. If anything feels wrong, the MHRA Yellow Card scheme lets you report suspected side effects directly, and you should contact a healthcare professional without delay.

The first Wegovy injection guide covers the injection technique itself (site rotation, angle, what to do if you see a bubble) which is a practical worry many people have before they start.

What the evidence shows about first-time results, and when to expect them

The STEP 1 clinical trial, published in the New England Journal of Medicine, followed 1,961 adults without diabetes over 68 weeks. Participants using semaglutide 2.4mg alongside lifestyle changes lost an average of around 15% of body weight. That figure carries important context: it reflects the full 68-week period, not the first month. In the early weeks, the dose is still low and the primary experience is adjustment, not dramatic change.

Weight loss typically becomes more noticeable as the dose increases, particularly from 1.0mg onward. What changes earlier is appetite, most people find they feel full sooner and think about food less, which is the mechanism doing its job. If you are considering how Wegovy compares with other licensed options, our weight loss treatments page covers the full picture, including tirzepatide (Mounjaro), which works through a different dual-receptor mechanism and showed greater average weight loss in the SURMOUNT-5 head-to-head trial.

Wegovy's effectiveness in NICE's assessment also led to its recommendation under NICE technology appraisal TA875, though NHS eligibility criteria are strict and tied to specialist services. Many people starting Wegovy for the first time do so through a private prescriber, which is where a service like ours comes in.

Getting the practical things right before your first pen

Wegovy pens are refrigerated between 2°C and 8°C. Before your first injection, the pen should reach room temperature, and the exact window for how long it can remain outside the fridge is detailed in the Patient Information Leaflet, always follow that rather than any general figure. Inject into the abdomen, thigh or upper arm, rotating sites between doses to avoid irritation building up at one spot.

Timing your weekly injection consistently makes the routine easier to sustain. If you are deciding when to schedule it, our page on choosing the best time for your first Wegovy injection walks through the practical factors worth considering, including how injection-day timing interacts with any side effects and your weekly schedule.

Women using oral contraceptives should be aware that NHS guidance addresses absorption interactions during GLP-1 treatment, worth raising with your prescriber before you start. The same applies if you are taking other regular medicines that need to be absorbed at predictable rates. For a broader look at the lived experience of beginning treatment, our taking Wegovy for the first time page draws together the practical details beyond the injection itself. And if you are still deciding whether to proceed, our guide for anyone using Wegovy for the first time is a sensible place to start before anything else.