How long until semaglutide is out of your system

Five weeks after your last injection, what the numbers mean day to day

You've decided to stop, or you're wondering what would happen if you did. Either way, you want a straight answer rather than a vague "it depends". Here it is: semaglutide's elimination half-life sits at roughly seven days in adults. That is a relatively long half-life compared to most medicines, which is exactly why Wegovy works as a once-weekly injection in the first place, steady concentrations, no daily peaks and troughs.

After your final dose, concentrations roughly halve each week. By week three, you are down to about 12.5% of peak levels. By week five, traces are below 3% of what was circulating at steady state. Clinically, most prescribers consider five weeks the practical clearance window, and if you want to understand how long it takes for semaglutide to get out of your system in more detail, that page breaks down the week-by-week picture. Trace amounts beyond that are unlikely to be pharmacologically active for most people.

The pace of clearance is broadly similar regardless of which maintenance dose you were on, because the half-life is a property of the molecule itself, not the quantity injected. If you want to understand how long Wegovy stays in your system at different stages of treatment, that page walks through the steady-state concentrations that build over the first few months too.

When do the appetite-suppressing effects wear off?

This is usually what people are actually asking. The pharmacokinetics tell you when the drug is gone; the experience of your appetite returning is a slightly different question.

Semaglutide slows gastric emptying and acts on appetite centres in the brain via GLP-1 receptors. As concentrations fall after stopping, those signals weaken. Most people notice hunger returning within one to two weeks of their last injection. For some it is sooner; a minority describe a more gradual shift. By around four weeks, the subjective appetite suppression is generally gone.

What follows that is the part worth being honest about. Clinical trials including STEP 1, published in the New England Journal of Medicine, followed participants after stopping semaglutide and found that weight regain began relatively quickly once the drug was out of the system and lifestyle support was reduced. Around two-thirds of lost weight was regained within a year of stopping in that extension cohort. That is not a reason to feel defeated, it reflects the biology of obesity, not a character flaw. It does explain why clinical guidance increasingly frames these medicines as long-term treatments rather than short courses. If you are weighing up whether to continue or stop, a conversation with a prescriber is more useful than a self-managed taper. Our Wegovy expected weight loss page puts the trial evidence into plain context.

Practical considerations: surgery, pregnancy, switching treatments

Knowing the clearance window matters for a few specific situations beyond simple curiosity.

If you are planning a surgical procedure, NHS England guidance is clear: tell your anaesthetist and surgical team that you have been on a GLP-1 medicine. Some anaesthetists request a pause before general anaesthesia because of the gastric-emptying effects, the exact period they ask for varies, so follow their instruction rather than a generic online figure.

Pregnancy is a harder line. Semaglutide is not recommended during pregnancy, breastfeeding, or when actively trying to conceive. The MHRA advises using effective contraception while on treatment and for a washout period after stopping before attempting conception. If you are trying to work out how long before semaglutide is out of your system ahead of planning a pregnancy, five weeks aligns with the pharmacokinetic clearance, but your prescriber or GP should advise on the specific timing for your circumstances.

If you are thinking about switching from Wegovy to another weight management treatment, the five-week clearance window is relevant to prescribers assessing overlap. People who have been asking themselves how long till Wegovy is out of your system ahead of a switch will find that our page on how long Wegovy is out of your system covers the week-by-week picture in more detail, though it is always worth bringing that question to your prescriber directly. For context on what other licensed options look like, our weight loss treatments overview covers what is currently available in the UK and how they differ.

If you have questions about how Wegovy fits your specific situation, or you are weighing whether treatment is right for you in the first place, start a free consultation with our prescribers. There is no obligation, and your answers are reviewed by a real clinician on the same day.