How Much Sterile Water Do You Need to Reconstitute 5mg Semaglutide?

Does licensed semaglutide for weight loss ever need reconstituting with sterile water?

No. Wegovy, the semaglutide injection licensed by the MHRA for weight management in the UK, is supplied as a pre-filled, pre-dosed pen. You take it out of the fridge, let it reach room temperature, and inject it once a week. The NHS medicines page for semaglutide describes this clearly: no powders, no diluent, no syringes drawn up by the patient.

Reconstitution (dissolving a lyophilised (freeze-dried) powder in sterile or bacteriostatic water) is a compounding technique used in research and certain clinical settings. It is not part of how any licensed semaglutide weight-loss product works in the UK. If you have come across instructions asking how much water you add to semaglutide, the product in question is not the licensed Wegovy that a GPhC-registered pharmacy can legally dispense. Our page on bacteriostatic water and semaglutide covers the distinction in more detail, but the short answer is the same: the mixing question does not apply to genuine UK-licensed treatment.

That matters enormously. The MHRA has warned publicly about counterfeit and unlicensed weight-loss products, including vials sold online. Fake pens have been found to contain insulin rather than semaglutide. A price that seems to undercut the market significantly, or a product format that requires home reconstitution, is a red flag worth taking seriously. If you are looking at a 5 mg vial specifically, our guide on how much water to add to 5mg semaglutide explains why that question only arises with unlicensed compounded products, not with anything a legitimate UK pharmacy can dispense.

What does legitimate semaglutide for weight loss actually cost in the UK?

UK private pricing for licensed Wegovy varies by dose and provider. Following Eli Lilly's list-price revision in autumn 2025 (which affected the tirzepatide market), the wider landscape for GLP-1 weight-loss medicines shifted; as widely reported, monthly costs for these treatments through private providers typically sit in the range of roughly £149 to £375 depending on the dose and the service. Any legitimate price includes a clinical assessment and a prescription, you cannot legally supply these medicines without one.

What headline prices do not always include is worth knowing before you compare. Some providers charge separately for the consultation, the prescription fee, delivery, and ongoing clinical support. A number quoted per pen or per month may not reflect what you actually pay by the time your treatment arrives. Our Wegovy cost guide sets out what to look for when you read a private provider's pricing page.

On the question of discount codes: if you have been searching for semaglutide vouchers or promotional offers, our page on Wegovy coupons explains why those searches tend to lead somewhere unreliable. Legitimate pharmacies dispensing prescription medicines do not run discount codes; the appearance of one should prompt the same caution as a reconstitution vial.

Why is 'cheapest' the wrong test for a prescription medicine?

A small saving on a prescription-only medicine is not actually a saving if the product is counterfeit, the dose is unverified, or no clinician has assessed whether the treatment is appropriate for you. The MHRA's guidance on GLP-1 medicines for weight loss is direct on this point: these are not medicines for quick or cosmetic use, and they carry real clinical considerations including gastrointestinal effects, interactions with oral contraceptives during dose increases for tirzepatide, and the need for ongoing monitoring.

A clinician reviews your consultation at nume personally, your answers reach a GPhC-registered prescriber, not a triage algorithm. That review happens the same day you submit. You can verify our pharmacy on the GPhC register at registration number 9012878. We are not the cheapest option available, and that is a deliberate choice: one price, one provider, full clinical oversight from first consultation to repeat prescriptions.

For a broader look at what licensed weight-loss treatment involves, the Wegovy treatment page covers the licensed indication, how the titration schedule works, and what a genuine supply-chain pen looks like when it arrives. If you are still deciding between treatment options, the weight-loss treatments overview may be a useful starting point.

How do you verify that a UK online pharmacy is legitimate before ordering?

The GPhC (General Pharmaceutical Council) registers every legally operating UK pharmacy, including those operating online. Searching the GPhC pharmacy register by name or registration number takes under a minute. A pharmacy dispensing prescription medicines without appearing on that register is operating illegally, regardless of how professional its website looks.

Beyond the register check, look at what the ordering process actually involves. A legitimate service will require you to complete a clinical consultation, verify your identity, and confirm your weight before a prescriber reviews your case. There will be no route to obtaining a prescription-only medicine without that assessment. If the path from landing page to checkout skips the clinical step entirely, that is your answer about the product being offered.

Our about us page sets out how nume's pharmacy and prescribing model is structured, and our FAQs cover common questions about the process. For anything more specific, contact our team directly.