Wegovy headaches: how to get rid of them and when to ask for help

You've just had your first injection and your head is pounding

It's an unpleasant surprise. You did everything right (took the pen out of the fridge the night before, injected at the right time, followed the steps in the leaflet) and now you're sitting with a dull ache behind your eyes. Headache during the first week or two of semaglutide is common, and it usually has a straightforward explanation: the medicine slows gastric emptying and changes how your gut signals the brain, which can temporarily disrupt fluid balance and blood sugar rhythm. Both of those shifts can trigger a headache.

The most effective immediate steps are also the most boring ones. Drink more water than you think you need, GI effects like nausea can quietly dehydrate you, and dehydration is a reliable headache trigger. Eat smaller, more regular meals rather than skipping food to avoid nausea; low blood sugar feeds the discomfort. If light and noise are making things worse, rest in a darker room. Over-the-counter paracetamol is generally appropriate, but check your full medication list with your prescriber first, particularly if you take other medicines regularly. Most people find the headaches thin out considerably after the first few injections, because the dose-escalation schedule gives the body time to adapt.

If the pain is severe, comes on suddenly, or is accompanied by visual changes, weakness or confusion, stop and get medical help straightaway, those are not typical Wegovy side effects and need assessment. The MHRA Yellow Card scheme also allows you to report any suspected side effect, which helps regulators monitor medicines in real-world use.

Why the dose schedule matters for headache frequency

Wegovy's dose-escalation pathway exists for good reason. Treatment starts low and steps up gradually (roughly every four weeks) so your system can adjust before the dose rises again. Headaches and other GI symptoms tend to cluster around injection one and after each step-up, then ease in the weeks that follow. That pattern is worth knowing, because some people assume the headaches mean the medicine isn't suiting them, when in fact they're inside a normal adjustment window.

Your prescriber decides when it's appropriate to increase your dose and whether to hold at a lower level longer if you're struggling. Changing the pace yourself (waiting longer, injecting more frequently) is not advisable without clinical sign-off. If you're finding each step-up difficult, that conversation with your clinician is the right move, not experimenting with timing. For more context on how side effects across the first weeks tend to unfold, the guide to managing Wegovy side effects walks through the adjustment period in more detail, including what's typical and what warrants a call to your team.

Nausea often accompanies the headache in early treatment, and they can reinforce each other, if you're feeling sick you drink less, and then the headache deepens. Addressing both at once is worth reading about; our page on managing nausea on Wegovy covers practical approaches that tend to help with both symptoms together.

Getting Wegovy legally and safely in the UK, and what to watch for online

Wegovy is a prescription-only medicine. The only legal route to it in the UK is a prescription issued after a clinical assessment by a qualified prescriber. There is no shortcut to that, and any seller offering it without that step is operating outside the law.

The MHRA has issued repeated warnings about counterfeit weight-loss pens sold online and via social media, some fake pens have contained insulin, which can be life-threatening in someone without diabetes. Large quantities of illegally traded pens have been seized across the UK, including a site producing counterfeit tirzepatide pens. You can check whether any online pharmacy is legitimate using the GPhC pharmacy register, every UK-regulated online pharmacy must be listed there. Red flags include sellers who contact you on social media, prices that seem far below the market rate, and anyone who can supply the medicine without a prescription. Report suspect sellers through the MHRA Yellow Card scheme.

For a full breakdown of how to find and verify a legitimate source, the guide to buying Wegovy online safely covers what to look for and what to avoid. If you're in the early stages of exploring treatment rather than already on it, how to get Wegovy in the UK explains the NHS and private routes clearly. Once you finish a course of treatment, our guide to disposing of Wegovy pens explains how to do so safely and in line with UK guidelines.

How nume works, and why clinical oversight makes a difference to side effects

At nume, every consultation is personally reviewed by a GPhC-registered Independent Prescriber. Not a chatbot, not an automated scoring system, a clinician who reads your answers and makes a clinical judgement. That matters for headaches specifically, because some cases (a history of migraines, blood pressure that sits high, other medicines that interact with semaglutide) change the picture, and a prescriber needs to see the full context.

If you order by 12pm Monday to Friday and are approved, your treatment goes out the same day and arrives with DPD the next working day, useful if you're planning around a busy patch at work or want treatment to arrive before a bank holiday weekend rather than after. Our prescribers are available for aftercare seven days a week, which means if you're a week into treatment and the headaches aren't letting up, you have somewhere to turn that isn't a general web search.

Wegovy is not available on the NHS through standard GP appointments for most people; the NHS route via specialist services typically involves waiting. Private treatment through a GPhC-registered pharmacy is the practical alternative for those who are clinically suitable. A full overview of the medicine itself is on our Wegovy information page, and if you want to explore treatment options more broadly, the weight-loss treatments overview is a good place to start.

When you're ready, start your free consultation and a prescriber will review your application the same day.