How Much Water Should You Drink on Wegovy, and What Does Treatment Actually Cost?

Why water intake is a genuine clinical question on Wegovy, not just lifestyle advice

A question our prescribers hear most weeks is some version of: 'I feel sick and I'm barely drinking anything, is that okay?' It isn't, and it matters for safety. Semaglutide reduces appetite and delays the time food takes to leave your stomach, which is exactly how it supports weight loss. But the same mechanism means nausea and reduced thirst can travel together, and if vomiting or diarrhoea are also present, fluid loss can build up faster than it feels.

The NHS guidance on semaglutide specifically lists dehydration as a risk to watch for, particularly in people who experience severe gastrointestinal side effects. The general recommendation is to keep up regular fluid intake, roughly 1.5–2 litres of water or other non-caffeinated, non-alcoholic drinks across the day. That figure is not fixed: body size, activity level, climate and how your body is responding all play a part, which is why your prescriber gives the definitive advice rather than any general guide. You can find more detail on daily fluid targets in our dedicated page on how much water to drink on Wegovy, and if you want a closer look at the numbers, our page covering how much water you should drink on Wegovy goes into further detail on individual factors that affect your daily target.

Practically, sipping small amounts regularly tends to work better than large glasses at once, especially in the first few weeks after a dose increase. Plain water is usually the easiest on the stomach. If you find nausea is preventing you from drinking adequately, tell your prescriber, it may affect the pace of your titration.

What private Wegovy treatment actually costs in the UK, and what that price should cover

Private Wegovy pricing in the UK is quoted per pen, per month, and it varies. That variation reflects dose (the starting pen and the maintenance pen are different prices), provider overhead, and what the headline figure actually includes. Since Eli Lilly's list-price adjustment for Mounjaro in September 2025 drew wider attention to GLP-1 pricing, there has been renewed interest in what 'the price' really means across the market, and we explain how our own pricing compares on our Wegovy price match page.

What headline prices often exclude is worth knowing before you compare. Some providers charge separately for the initial consultation, the prescription fee, delivery, and ongoing clinical check-ins. A per-pen price that looks sharp may become considerably less so once those are added. The Wegovy price breakdown we publish walks through each component in detail, so you know what to ask any provider before you commit. NHS England's guidance on weight-management injections also sets out what a complete, clinically supported treatment pathway should include, useful context when evaluating what any private service actually offers.

At nume, one price covers the consultation, the prescription, the medicine and next-working-day DPD delivery. We are not the cheapest option in the market, and that is a deliberate choice. Clinical review before every order, seven-day aftercare and a GPhC-registered pharmacy are not optional extras we stripped out to sharpen a headline number. Current treatment pricing is on our treatment page.

Why 'cheapest' is the wrong question for a prescription medicine

For a Prescription-Only Medicine, the price is only one part of the picture. The MHRA has issued public warnings about counterfeit weight-loss pens sold through unverified online channels, pens that have, in documented cases, contained insulin rather than semaglutide. In 2025 alone, enforcement operations seized around 20 million doses of illegally traded weight-loss medicines with an estimated street value of around £45 million. A first illicit UK manufacturing site for fake tirzepatide pens was raided in late 2025.

The right question is not which provider quotes the lowest number, but whether the provider is GPhC-registered, whether a qualified prescriber is reviewing your case, and whether the medicine is sourced through the licensed UK supply chain. You can check any online pharmacy on the GPhC register, nume's premises registration number is 9012878. Red flags include pens offered without a prescription, social-media sellers, and prices far below the typical private market range. You can report suspect sellers at the MHRA's Yellow Card scheme.

Wegovy is a prescription medicine requiring ongoing clinical oversight, dose titration, side-effect management, hydration guidance, and periodic review of whether treatment is still appropriate for you. That infrastructure is part of what a legitimate price pays for. Our clinical team reviews every order personally, and our Wegovy overview sets out exactly what the treatment involves from first pen to maintenance dose, including preparation questions such as how much water you add to semaglutide and how much water you mix with semaglutide if you are using a reconstituted form. If you have questions before starting, our FAQs cover the most common ones.