If you're starting a GLP-1 medication, you won't begin at the full dose. Every GLP-1 weight loss injection uses a process called titration — gradually increasing the dose over several weeks to allow your body to adjust. This is deliberate and important: it significantly reduces the nausea and digestive side effects that are most common when you first start or when the dose goes up.
Here's the dosing schedule for every GLP-1 weight loss injection available in the UK.
Mounjaro (tirzepatide)
Mounjaro increases every 4 weeks. The full titration takes approximately 20 weeks to reach the maximum dose.1
| Period | Weekly dose | What to expect |
|---|---|---|
| Weeks 1–4 | 2.5mg | Starting dose. Primarily for tolerability — don't expect much weight loss yet |
| Weeks 5–8 | 5mg | First therapeutic dose. Some appetite suppression begins. Mild nausea possible |
| Weeks 9–12 | 7.5mg | Appetite reduction more noticeable. Weight loss typically starts |
| Weeks 13–16 | 10mg | Stronger effect. Most people are losing weight consistently by this point |
| Weeks 17–20 | 12.5mg | Approaching maximum. Evaluate whether you need to go higher |
| Week 21+ | 15mg | Maximum maintenance dose. Stay here long-term if tolerated |
Wegovy (semaglutide)
Wegovy also increases every 4 weeks. The standard titration takes about 16 weeks to reach the 2.4mg maintenance dose, with an optional further increase to 7.2mg.2
| Period | Weekly dose | What to expect |
|---|---|---|
| Weeks 1–4 | 0.25mg | Starting dose. Tolerability phase — very low dose |
| Weeks 5–8 | 0.5mg | Slight appetite changes may begin |
| Weeks 9–12 | 1mg | Appetite suppression becomes more noticeable. Weight loss begins for most |
| Weeks 13–16 | 1.7mg | Stronger effect. Nausea most likely during this escalation |
| Week 17+ | 2.4mg | Standard maintenance dose (~15% weight loss in trials) |
| Optional | 7.2mg | Higher dose approved Jan 2026 (~20.7% weight loss). Discuss with prescriber |
Saxenda (liraglutide)
Saxenda titrates weekly rather than every 4 weeks, reaching maintenance in about 5 weeks. However, because it's a daily injection, you take the dose every day.3
| Period | Daily dose | What to expect |
|---|---|---|
| Week 1 | 0.6mg daily | Starting dose — tolerability |
| Week 2 | 1.2mg daily | First increase |
| Week 3 | 1.8mg daily | Appetite suppression begins |
| Week 4 | 2.4mg daily | Approaching maintenance |
| Week 5+ | 3.0mg daily | Maintenance dose (~8% weight loss in trials) |
Why titration matters
Titration isn't optional — it's a fundamental part of how these medications are prescribed. Starting at the full dose would cause severe nausea and vomiting for most people, potentially leading them to abandon treatment entirely. The gradual increase allows your body to adapt to the medication's effects on your digestive system.
Side effects (particularly nausea) are most common during the first week or two at a new dose, then typically improve as your body adjusts. If side effects are severe at any point, your prescriber may recommend staying at the current dose for an extra period before increasing.
Do you have to reach the maximum dose?
No. The maximum dose isn't a target that everyone needs to hit. If you're losing weight effectively and tolerating a mid-range dose well, there's no clinical reason to increase further just because a higher dose exists. Your prescriber will work with you to find the dose that balances effectiveness with tolerability.
Conversely, if you're not seeing results at lower doses, increasing to the maximum may help — the weight loss effect is dose-dependent. This is a conversation to have with your prescriber at each review.
When does weight loss start?
Most people don't see significant weight loss during the first 4 weeks (the starting dose). Meaningful weight loss typically begins around weeks 5–8 for Mounjaro and weeks 9–12 for Wegovy, as the dose reaches therapeutic levels. Weight loss then continues and generally accelerates as the dose increases, with the most rapid loss often occurring between months 3 and 9 of treatment.
For a month-by-month breakdown, see our GLP-1 weight loss timeline.
Practical tips for each dose increase
- Eat smaller meals — your stomach is emptying more slowly, so large portions will make you feel uncomfortably full or nauseous
- Stay hydrated — especially important if you experience vomiting or diarrhoea during adjustment
- Avoid high-fat and very rich foods during the first few days at a new dose — these are more likely to trigger nausea
- Time your injection consistently — same day each week (Mounjaro/Wegovy), with or without food
- Keep a symptom diary — tracking side effects helps you and your prescriber decide when it's safe to increase
Related articles
SafetyGLP-1 Side Effects: What to Expect
Common and rare side effects with practical management tips.
PracticalHow to Inject Mounjaro: Step-by-Step
Injection sites, technique, storage, and missed doses.
ResultsGLP-1 Weight Loss Timeline: Month by Month
What to expect at each stage of treatment.