UK GLP-1 Dosing: 4 week steps to cut side effects and protect muscle
GLP-1 medicines are started at low doses and escalated at manufacturer-recommended intervals to a tolerated maintenance dose. This guide covers semaglutide (oral and injectable), tirzepatide, liraglutide, exenatide and dulaglutide, with the schedules used in UK prescribing. Always confirm your exact dose with your prescriber, and never start or continue any of these medicines during pregnancy or breastfeeding.
TL;DR:
- Most GLP-1 medicines require minimum four-week intervals at each dose before escalation, except liraglutide, which allows one-week steps.
- Switching between form factors, such as injectable and oral semaglutide, alters absorption and should only be managed with clinical guidance.
- Gastrointestinal side effects like nausea and vomiting are common during dose increases and can be mitigated by hydration, diet adjustments, and careful monitoring.
- Missed doses of semaglutide can be taken within five days, while tirzepatide must be used within four days; never double doses to compensate.
- These medicines are contraindicated during pregnancy and breastfeeding, and effective contraception is advised during treatment.
Table of Contents
- Dosing by medication: semaglutide, tirzepatide, liraglutide and more
- Titration schedules at a glance
- Taking GLP-1 medicines correctly day to day
- Side effects, interactions and when to get urgent help
- Missed doses, changing your schedule and stopping safely
- What structured support adds to safe dosing
- Our take: titration charts are a starting point, not the plan
- Getting clinically governed support for your GLP-1 journey
- FAQ
- Sources
Dosing by medication: semaglutide, tirzepatide, liraglutide and more
Each GLP-1 medicine has its own titration pattern, and the step sizes, intervals and maximum doses differ enough that mixing them up is a genuine risk. Here is what the product information sets out for the medicines most commonly prescribed.
- Semaglutide, injectable (Wegovy for weight management, Ozempic for type 2 diabetes): Wegovy escalates over 16 weeks, moving from 0.25 mg weekly for four weeks to 0.5 mg, then 1 mg, then 1.7 mg, each for four weeks, reaching a maintenance dose of 2.4 mg. Prescribers may raise this to 7.2 mg after at least four weeks on 2.4 mg. Ozempic, used for blood glucose control, follows a gentler path: 0.25 mg weekly, stepping up to 0.5 mg after four weeks, with further increases to 1 mg and 2 mg possible at the same four-week minimum spacing. Weekly doses above 2 mg are not recommended for glycaemic control.
- Semaglutide, oral (Rybelsus): This version steps up monthly rather than weekly, typically 3 mg for the first month, then 7 mg, then 14 mg, and must be taken fasted. Switching between the oral and injectable forms changes how much reaches your bloodstream, so any switch needs clinical supervision rather than a DIY swap, a point we cover in more depth in our Wegovy injection vs tablets comparison.
- Tirzepatide (Mounjaro): Starts at 2.5 mg once weekly for four weeks, then increases by 2.5 mg at intervals of at least four weeks, through 5 mg, 10 mg and up to a maximum of 15 mg.
- Liraglutide (Saxenda): For weight management, the starting dose is 0.6 mg once daily, rising by 0.6 mg each week to a maintenance dose of 3.0 mg. If a step isn't tolerated after two weeks, the SmPC supports stepping back down or stopping rather than pushing through.
- Exenatide and dulaglutide: Both are older GLP-1s, less commonly used for weight management specifically and more often seen in type 2 diabetes care, with dosing and frequency set out alongside the others in NICE CKS prescribing guidance.
For a direct head-to-head on how semaglutide and liraglutide differ in practice, our Wegovy vs Saxenda comparison walks through the trade-offs.
Titration schedules at a glance
Use this as a quick reference only. Your prescriber's instructions and the medicine's own product information always take precedence over any chart.
Switching between formulations, such as moving from injectable to oral semaglutide, can change how predictably the medicine is absorbed, so this isn't something to manage without clinical input.
Taking GLP-1 medicines correctly day to day
Getting the practical details right cuts down on side effects and wasted doses.
- Oral semaglutide (Rybelsus): take it fasted, with no more than 120 mL of water, and wait at least 30 minutes before eating, drinking anything else, or taking other oral medicines.
- Weekly injectables: pick a day that suits your routine and stick to it; if you need to change the day, leave at least 72 hours between doses.
- Injection sites: the abdomen, thigh and upper arm all work, and rotating between them reduces irritation at any one spot.
- Pen handling: keep spare needles on hand, never reuse a needle, and follow the priming steps in the device instructions each time.
- Persistent nausea or vomiting: this is a reason to hold off on the next dose increase and speak to your clinician rather than push through.
Pro Tip: During a dose increase, eat smaller, plainer meals for the first few days and keep strongly flavoured drinks like coffee away from mealtimes, it tends to make nausea noticeably more manageable.
Side effects, interactions and when to get urgent help
Gastrointestinal side effects are the most common complaint with every GLP-1 medicine on this list, and they tend to cluster around dose increases rather than staying constant.
More than 1 in 10 patients report gastrointestinal side effects such as nausea, vomiting and diarrhoea, according to MHRA drug safety guidance. The same guidance flags dehydration as a real risk during flare-ups, so keeping fluids up matters more than people expect.
- Dehydration: severe or persistent vomiting needs medical review, not just fluids at home.
- Hypoglycaemia: combining a GLP-1 with insulin or a sulphonylurea raises the risk of low blood sugar; Diabetes UK guidance notes that doses of those other medicines may need reducing, alongside closer glucose monitoring.
- Pancreatitis warning signs: severe, persistent abdominal pain that spreads to the back warrants urgent assessment, not a wait-and-see approach.
- Pregnancy and breastfeeding: these medicines are not used in pregnancy or while breastfeeding; effective contraception is advised, and treatment should stop if pregnancy is planned or confirmed.
Our guide to GLP-1 side effects covers nausea and constipation management in more detail, including when symptoms cross the line into needing medical attention.
Missed doses, changing your schedule and stopping safely
Each medicine has its own rule for a missed dose, and guessing is riskier than it sounds.
- Semaglutide (injectable): take the missed dose within 5 days if you remember in time; beyond that, skip it and resume your normal schedule.
- Tirzepatide: the window is shorter, within 4 days; after that, skip and wait for the next scheduled dose.
- Liraglutide (daily): follow the specific missed-dose window in the product information and never double up to make up for a skipped day.
- Changing your injection day: leave a minimum of 72 hours between doses when shifting to a new weekly slot.
- Stopping treatment: this is a decision for you and your prescriber together, particularly if you have diabetes, since stopping can affect blood glucose control. Our article on stopping GLP-1 treatment covers what to expect afterwards, including appetite and weight changes.
What structured support adds to safe dosing
Following a titration schedule correctly is only part of the picture. What we see matter just as much in practice is protecting muscle and staying properly hydrated while your body adjusts, especially in the first few weeks of any dose increase.
Simple measures go a long way: enough protein at each meal, a couple of sessions of resistance training a week, and deliberate fluid intake around dose days rather than only when thirst kicks in. We cover the detail in our pieces on preventing GLP-1 muscle loss and practical steps for men on GLP-1 medicines. Where side effects are getting in the way of eating or sleeping properly, that's the point to flag it with a clinician rather than quietly struggling through an escalation.
Our take: titration charts are a starting point, not the plan
The dosing numbers matter, but they're the easy part. What tends to get underrated is everything around the injection itself: whether you're eating enough protein to hold onto muscle, whether you're drinking enough water on the days nausea hits hardest, and whether you've actually told anyone that a dose increase is coming so you can plan around it.
Conventional advice often treats titration as a mechanical process, follow the chart, increase on schedule, done. In practice, the right pace for you depends on how your body responds at each step, not just how many weeks have passed. Tolerating 1 mg of semaglutide badly is a legitimate reason to pause an increase, not push through it because the calendar says so.
If we had to pick one priority, it's this: treat side effects as information, not an inconvenience to tolerate. Persistent nausea, fatigue or GI upset is your body telling you the current dose needs more time, and that's worth listening to before chasing the next step up.
— Matt O’Brien
Getting clinically governed support for your GLP-1 journey
We built the Structured Weight-Loss Programme around exactly this gap: clinical assessment, prescribing partner support, and ongoing lifestyle guidance, so dosing decisions aren't made in isolation.
Every stage runs alongside regulated prescribing and monitoring partners, with check-ins built in rather than left to chance. If you're weighing up whether a structured path suits you better than going it alone, our Structured Weight-Loss Shift Programme comparison sets out what's included and what to expect.
This article is general information, not a substitute for advice from a qualified doctor. Consult a qualified healthcare professional about your own circumstances before acting on anything here.
FAQ
What is the correct starting dose for semaglutide?
Injectable semaglutide for weight management starts at 0.25 mg once weekly for four weeks, a dose too low for weight loss itself but designed to let your body adjust. Oral semaglutide starts at 3 mg daily for the first month under the same principle, detailed in Ozempic's product information.
How quickly can you increase a GLP-1 dose?
Most GLP-1 medicines require a minimum of four weeks at each dose before increasing, with liraglutide being the exception at one week per step. Increasing faster than the product information allows raises the risk of severe nausea and vomiting.
What happens if you miss a weekly GLP-1 injection?
For semaglutide, you can take the missed dose within 5 days of the scheduled time; beyond that, skip it and wait for your next planned dose. Tirzepatide's window is shorter, within 4 days, after which you should also skip rather than double up.
Can you take GLP-1 medicines while pregnant?
No, GLP-1 medicines including semaglutide, tirzepatide and liraglutide are not used during pregnancy or breastfeeding. Effective contraception is advised while on treatment, and anyone planning a pregnancy should speak to their prescriber about stopping beforehand.
What is the maximum dose of tirzepatide?
The maximum licensed dose of tirzepatide is 15 mg once weekly, reached by increasing from a 2.5 mg starting dose in 2.5 mg steps no sooner than every four weeks, as set out in MHRA dosing guidance. Not everyone needs to reach the top dose, many people reach a good response at 5 mg or 10 mg.
Sources
- MHRA announcement — semaglutide up to 7.2 mg (Wegovy)
- Ozempic SmPC (semaglutide) — posology and administration
- CKS (NICE) — GLP‑1 receptor agonists prescribing information