Semaglutide solution for weight loss: the practical picture

Step 1, understanding what semaglutide solution actually contains

Wegovy is the brand name for semaglutide in its injectable form for weight management, manufactured by Novo Nordisk. Each pre-filled pen delivers a clear, colourless solution subcutaneously (under the skin) at the abdomen, thigh, or upper arm. You rotate injection sites week to week. The active molecule, semaglutide, is a GLP-1 receptor agonist: it mimics a gut hormone that signals fullness to the brain, slows how quickly the stomach empties, and reduces the drive to eat. This is a single-receptor mechanism, in contrast to tirzepatide, which you can read about on our weight-loss treatment overview. Each pen comes pre-loaded and is designed for straightforward self-administration. There is no reconstitution involved, the solution is ready to use, which is worth clarifying because if you want to understand how semaglutide works as a medicine, some older compounded or research-grade preparations did require mixing. The distinction between ready-to-use Wegovy pens and preparations that require reconstitution is an important one for anyone researching this online.

Step 2, the titration schedule and what it is designed to do

Semaglutide solution is not started at its full maintenance dose. The journey begins at 0.25 mg weekly for the first month, a low dose whose purpose is tolerability rather than weight loss. From there, the prescriber increases the dose in roughly four-week steps through 0.5 mg, 1.0 mg and 1.7 mg, arriving at the 2.4 mg maintenance dose. In January 2026 the MHRA also approved a 7.2 mg maintenance dose (initially delivered as three 2.4 mg pens in a single week, and then via a dedicated single-dose pen approved on 14 April 2026) for eligible adults with a BMI of 30 or above. Trial data for the 7.2 mg dose reported an average weight reduction of around 20.7% over 72 weeks, bringing its results closer to those seen with the highest tirzepatide doses. Pacing the titration this way reduces the likelihood of the nausea, diarrhoea and other gastrointestinal effects that are most common when starting or increasing the dose. Your prescriber decides the pace based on how you are tolerating each level; timing decisions belong with the clinician and the patient information leaflet, not with general copy. Our guide to semaglutide 1 mg dosing sets out what licensed weight-management use looks like at each stage, alongside the Wegovy treatment page.

Step 3, the evidence base and what it means for real-world expectations

The pivotal trial for semaglutide 2.4 mg was STEP 1, a 68-week study published in the New England Journal of Medicine. Participants achieved an average weight reduction of around 15%, a meaningful result by any clinical measure, though individual outcomes varied widely. Weight loss is shaped by biology, starting weight, adherence and the lifestyle changes made alongside treatment; the trial average is a reference point, not a promise. NICE recommends semaglutide for weight management under its guidance TA875, subject to use within a specialist weight management service for a maximum of two years, and with BMI and comorbidity criteria that differ from the private-prescription route. On the NHS, access depends on specialist referral and often involves a waiting list. Private prescribing through a regulated pharmacy removes those barriers, the same clinical eligibility principles apply, but assessment is completed before dispensing rather than after a referral queue.

Step 4, storing the pen and staying safe throughout treatment

Once you have the pen, storage matters. Semaglutide solution must be refrigerated between 2°C and 8°C; there is a limited window during which it can be kept at room temperature when travelling, but the exact duration is set by the licensed product information rather than by general advice. Always check the patient information leaflet that comes with your pen. The most common side effects are gastrointestinal: nausea is reported most often, alongside stomach discomfort, loose stools, constipation and fatigue, typically most noticeable in the first weeks or after a dose increase, then settling. Severe, persistent abdominal pain that spreads to the back needs urgent medical attention; pancreatitis is a known but infrequent risk. The MHRA encourages patients to report any suspected side effects through the Yellow Card scheme, which also accepts reports about suspect or counterfeit products. If you have questions during treatment, our support team is available seven days a week. For anyone wondering whether stopping treatment abruptly is ever appropriate, this question is addressed in detail separately, it is genuinely one worth reading before making any changes. Cost context, including how private prices are structured, is covered on our Wegovy pricing and access page. If you'd like to talk through whether semaglutide solution is clinically suitable for you, speak to our prescribers through a free consultation.