What to do before starting Wegovy: a practical guide

What should you tell your prescriber before Wegovy is prescribed?

The most useful thing you can do before starting is to write down every medicine, supplement and over-the-counter product you take regularly, and our guide on what to do before taking Wegovy walks you through exactly how to prepare that information. Wegovy slows how quickly food leaves your stomach, and that same slowing can affect how quickly your body absorbs other medicines. Oral contraceptive pills are the clearest example: if you take the pill, NHS guidance recommends adding a non-oral method of contraception for the first four weeks of treatment. Your prescriber also needs to know about any history of pancreatitis, gallbladder disease or medullary thyroid carcinoma, because these affect whether Wegovy is suitable at all.

It is also worth mentioning if you are on any medicines where even a small shift in absorption timing matters, blood-pressure tablets, thyroid medication and anticoagulants are common ones. You do not need to stop them; the prescriber needs the information to make a safe decision. The NHS semaglutide medicines page lists categories of interaction to raise with your doctor or pharmacist.

At our pharmacy, every consultation is read by a GPhC-registered Independent Prescriber before any treatment is approved or dispatched. They look at the full picture, not a checklist. That is the right time to raise anything you are unsure about, our contact team can also answer questions before you start.

How should you adjust your diet in the days before your first injection?

You do not need a special pre-treatment diet, but a few straightforward changes reduce the likelihood of a rough first week, and our page covering things to know before starting Wegovy goes into each of them in more detail. Wegovy slows gastric emptying noticeably from the first dose, so arriving at your first injection already eating very large portions or high-fat meals tends to amplify nausea and bloating. Trimming portion sizes modestly a few days before you start gives your stomach a chance to adjust to a new baseline before semaglutide adds to that effect.

Alcohol is worth reducing too. It contributes to nausea on its own, and combining it with the GI effects of a new GLP-1 medicine often makes the first week harder than it needs to be. Staying well hydrated matters more than it might sound: one of the risks during early treatment is that persistent nausea leads to reduced fluid intake, which can spiral into dehydration. Starting with a good hydration habit means you have a buffer.

Protein is the other practical priority. As appetite drops, many people find that overall food intake falls faster than they expected, and if most of what remains is carbohydrate, muscle loss can follow. Building a habit of protein-first meals before treatment starts means the pattern is already in place when you need it. The NHS offers straightforward healthy weight and diet guidance that works well alongside GLP-1 treatment.

What do you need to know about the first few weeks of side effects?

Knowing what to expect is genuinely different from being warned, and our detailed guide on what to do when starting Wegovy covers the practical steps that help you through those early weeks. Wegovy's most common side effects are gastrointestinal, nausea, loose stools, constipation, reflux, burping and sometimes fatigue or mild headaches. They tend to be most noticeable in the days after the first injection and after each dose increase. Most people find they settle within a week or two. That is the licensed dose schedule working as intended: the escalation exists precisely to give your body time to adjust.

A small number of people experience something more significant. Severe, persistent stomach pain that reaches into the back (especially with vomiting) needs prompt medical attention. This is a sign to rule out pancreatitis, which is a rare but serious known risk. The MHRA highlighted acute pancreatitis in a Drug Safety Update for GLP-1 medicines in January 2026 and is clear that any such symptoms warrant urgent review. You can also report unexpected side effects at Yellow Card, the MHRA's reporting service.

Practically: know where your nearest urgent care or A&E is before you inject for the first time. Keep the Patient Information Leaflet. Wegovy arrives in plain, unbranded packaging, your pen will come tracked by DPD and should go straight into the fridge door when it arrives. Check injection sites (abdomen, thigh or upper arm), rotate them, and read the leaflet before you use the pen rather than after.

Is there anything to sort financially or logistically before you begin?

Treatment costs are worth thinking through before you commit, rather than after the first pen has arrived, and our full overview of starting Wegovy covers both the financial and practical steps to work through in advance. Wegovy is a prescription-only medicine and is not available to buy without a valid prescription following a clinical assessment. On the NHS, access is currently limited to people meeting specific BMI and comorbidity thresholds through specialist weight management services; waiting times vary widely. Private treatment through a regulated online pharmacy is the route most people take when they do not meet NHS criteria or prefer not to wait.

Our Wegovy cost page sets out what private treatment typically involves. The price you see from any legitimate provider should include the prescription and clinical review, if it does not, that is a practical reason to look more carefully at what you are actually buying. For a prescription medicine, the question of cost is better framed around what is included than around which number is lowest.

Eligibility covers more than your BMI figure. A full clinical picture is what any GPhC-registered prescriber works from. If you want to understand where you stand before committing to a consultation, our FAQs cover the most common eligibility questions. When you are ready, a free consultation with our prescribers is the next step. There is no obligation, and your answers are reviewed by a real clinician the same day.