How much water do you add to 5mg semaglutide — and why this question is a safety signal

You've been handed a vial and told to add water: here's what that means

Picture the scenario: you've found semaglutide online at a price that seemed reasonable. It arrived as a small glass vial (powder or liquid) with a separate syringe and instructions to add bacteriostatic water before injecting. You're now trying to work out the right water volume for what's labelled 5mg.

Licensed semaglutide for weight management in the UK does not work this way. Wegovy is supplied as a pre-filled injection pen: the dose is pre-set, the needle is covered, and nothing is mixed. The licensed UK maintenance doses run from 0.25mg up to 2.4mg weekly, with a higher 7.2mg single-dose pen approved by the MHRA in April 2026 for adults with a BMI of 30 or above. A 5mg semaglutide vial sits entirely outside that schedule. If you want to understand the general question of water and semaglutide more fully, that page covers the licensed products in detail.

Vials requiring reconstitution are not MHRA-licensed products for weight management. The MHRA has warned publicly about counterfeit and unlicensed weight-loss injectables sold online, some seized products have contained insulin rather than the labelled compound, leading to hospitalisations. Reporting a suspect product is straightforward via the MHRA's Yellow Card scheme. The search you just ran is a useful prompt to pause and check what you've actually been sent, and if you're wondering about staying properly hydrated while on this medication, our guide on how much water to drink on semaglutide covers that in full.

How private Wegovy pricing works in the UK, the honest picture

UK private weight-loss treatment is priced per pen per month, and it varies between providers. Since Eli Lilly raised Mounjaro's UK list price in September 2025, the broader market shifted, and Wegovy pricing has moved alongside it. Typical private prices reported across the market since then range roughly £149 to £375 per month depending on dose and provider, these are widely reported figures, not specific quotes. For a fuller breakdown of what drives that range, the Wegovy price page sets it out clearly.

What a headline price often doesn't tell you is what's inside it. Some providers charge separately for the initial consultation, the prescription itself, delivery, and any aftercare. A figure that looks competitive at first glance can climb once those are added. It's worth spending sixty seconds reading the checkout page of any provider carefully: does the quoted price include clinical review, or is that a separate line? Is there a delivery charge? Is follow-up support included or billed separately? That one-minute check is something our prescribers suggest to anyone comparing options.

The full cost of semaglutide in the UK covers how to read a provider's pricing page, and what questions to ask before committing.

What nume's price actually includes, and why we're not competing on cost

At nume, one price covers everything: the clinical consultation, the prescription, the treatment, and free next-working-day tracked delivery by DPD in plain packaging. There are no hidden charges, no subscription you need to cancel, and no automatic renewal. Every repeat order goes through a fresh clinical review, a real GPhC-registered prescriber reads your case each time, not a system that rubber-stamps the last decision.

We don't pitch ourselves as the lowest-cost option. That's a deliberate choice. The services built around safety (live weight verification before dispensing, photo-ID checks, GP notification in line with GPhC guidance, seven-day aftercare) cost something to run properly. A price low enough to undercut that infrastructure is a price that's cut something out. What affordable Wegovy actually looks like is a question worth reading before assuming the cheapest listing is also the safest one.

If you're already on treatment elsewhere and want to understand whether transferring is straightforward, the nume team page explains how transfer patients are assessed. Nothing automatic, evidence of your current dose is reviewed before anything changes.

For a prescription medicine, 'cheapest' answers the wrong question

Wegovy is a Prescription-Only Medicine. A clinician assesses whether it's appropriate for you before it's dispensed, that's not a formality, it's the legal and clinical basis of the whole process. The NHS semaglutide page explains the medicine's profile clearly, including contraindications that make it unsuitable for some people regardless of their BMI.

When a vial arrives labelled 5mg semaglutide and requires you to add water, the question of how much water is the least important thing to resolve. The questions that matter are: who manufactured this, where from, under what quality controls, and has a prescriber who has reviewed your medical history decided this is appropriate for you? Unlicensed products bypass every one of those steps. The MHRA's guidance on GLP-1 medicines for weight loss is direct on this point.

If you want to start weight management treatment through a regulated route, speak to our prescribers, the consultation is free, and you'll know the same day whether you're clinically suitable.