Key points
- Weekly semaglutide (Wegovy) produces roughly twice the weight loss of daily liraglutide (Saxenda)
- Weekly dosing is associated with better long-term adherence and patient satisfaction
- Weekly tirzepatide (Mounjaro) offers the greatest weight loss of all currently available options
- Daily liraglutide remains available for patients who prefer or tolerate it better
- An oral semaglutide tablet may become available in the UK from 2027
The options: daily vs weekly
In the UK, patients currently have access to both daily and weekly injectable GLP-1 medications for weight management. Understanding the differences helps patients and prescribers make informed choices.
Daily injection: liraglutide (Saxenda)
Liraglutide (Saxenda) was the first GLP-1 receptor agonist approved specifically for weight management. Licensed by the MHRA in 2017 for adults with a BMI of 30 or above (or 27 with weight-related comorbidities), it requires a daily subcutaneous injection at a dose of 3.0 mg.
Liraglutide was originally developed for type 2 diabetes (marketed as Victoza at lower doses) and was found to produce meaningful weight loss as an additional benefit. Saxenda is the higher-dose formulation specifically indicated for weight management.
Weekly injections: semaglutide and tirzepatide
Semaglutide (Wegovy) is a once-weekly injection at a maintenance dose of 2.4 mg. It is a more potent GLP-1 agonist than liraglutide, engineered to have a half-life of approximately 7 days. Licensed by the MHRA for weight management and, from April 2026, for cardiovascular risk reduction.
Tirzepatide (Mounjaro) is a once-weekly dual GLP-1/GIP receptor agonist at maintenance doses of 5 mg, 10 mg or 15 mg. It offers the greatest weight loss of any currently approved medication in this class.
Head-to-head efficacy comparison
The most important question for many patients is: how much weight will I lose? Clinical trial data provide clear answers.
| Medication | Frequency | Mean weight loss | Trial |
|---|---|---|---|
| Liraglutide 3.0 mg (Saxenda) | Daily | ~6–8% | SCALE trials |
| Semaglutide 2.4 mg (Wegovy) | Weekly | ~15–17% | STEP trials |
| Tirzepatide 15 mg (Mounjaro) | Weekly | ~20–22% | SURMOUNT trials |
The STEP 8 trial directly compared semaglutide 2.4 mg to liraglutide 3.0 mg over 68 weeks. Semaglutide produced a mean weight loss of 15.8 per cent compared with 6.4 per cent for liraglutide. The difference was statistically significant and clinically meaningful.
Important context: These are average results from clinical trials. Individual weight loss varies considerably and depends on factors including adherence, diet, exercise and baseline metabolic health. Some patients respond better to one medication than another.
Convenience and adherence
The frequency of dosing has a significant impact on treatment adherence and patient quality of life.
The burden of daily injections
Saxenda requires 365 injections per year. For many patients, the daily routine becomes burdensome over time. Common challenges include:
- Remembering to inject at roughly the same time each day
- Carrying the pen when travelling or eating out
- Managing injection-site rotation across 365 injections annually
- The psychological fatigue of a daily medical procedure
- Social situations where injecting can feel awkward
The convenience of weekly injections
Wegovy and Mounjaro require just 52 injections per year. Patients consistently report greater satisfaction and ease with weekly dosing:
- Choose a fixed day of the week (for example, every Sunday evening)
- Less disruption to daily routine
- Easier to travel with (one pen covers 4 weeks)
- Fewer injection-site reactions
- Generally easier to remember than daily dosing
What the adherence data shows
Real-world prescription data from the UK and internationally consistently shows higher persistence rates with weekly GLP-1 injections compared with daily ones. A 2024 analysis published in Diabetes, Obesity and Metabolism found that 12-month persistence was approximately 55 to 60 per cent for weekly semaglutide compared with 30 to 40 per cent for daily liraglutide. Better adherence translates directly into better outcomes.
Side effect comparison
Both daily and weekly GLP-1 injections share the same class of side effects, primarily gastrointestinal. However, the pattern and severity can differ.
| Side effect | Liraglutide (daily) | Semaglutide (weekly) | Tirzepatide (weekly) |
|---|---|---|---|
| Nausea | ~40% | ~44% | ~25–30% |
| Vomiting | ~16% | ~25% | ~10–15% |
| Diarrhoea | ~20% | ~30% | ~15–20% |
| Constipation | ~10% | ~10% | ~10–15% |
Semaglutide tends to produce more gastrointestinal side effects during dose escalation, which is expected given its greater potency. However, these side effects typically improve over time and are managed by the gradual dose-escalation schedule.
Tirzepatide appears to have a somewhat milder gastrointestinal profile than semaglutide at equivalent levels of weight loss, which may be related to its dual receptor mechanism.
Managing side effects: Regardless of which injection you take, eating smaller meals, avoiding fatty foods and staying hydrated can significantly reduce gastrointestinal side effects. See our full guide to GLP-1 side effects.
Cost comparison in the UK
Cost can be a deciding factor, particularly for patients paying privately.
| Medication | Approximate monthly cost (private) | NHS availability |
|---|---|---|
| Saxenda (liraglutide) | £150–220 | Limited; some specialist services |
| Wegovy (semaglutide) | £200–300 | Yes; specialist weight management |
| Mounjaro (tirzepatide) | £180–280 | Yes; some GPs and specialist services |
On the NHS, Wegovy is available through specialist weight management services for patients meeting the criteria (BMI 35+, or 32.5+ for certain ethnic groups, or 27+ with cardiovascular disease). Mounjaro has been available through some GPs since June 2025. Saxenda is available but increasingly being replaced by the newer weekly options.
For full pricing information, see our guide to online weight loss prescriptions.
Patient experience: what people say
Patient forums and clinical feedback consistently highlight several themes when comparing daily and weekly injections.
Switching from daily to weekly
Many patients who have used Saxenda and then switched to Wegovy or Mounjaro report:
- Greater convenience and reduction in treatment burden
- More pronounced appetite suppression
- Better weight loss results
- Initial nausea that can be more intense during dose escalation but that settles
- Overall preference for the weekly schedule
Who might still prefer daily injections
While weekly injections are preferred by most patients, some individuals may benefit from daily dosing:
- Patients who experience prolonged nausea with weekly injections and prefer the more even drug levels of daily dosing
- Those who find the daily routine easier to integrate into existing medication schedules
- Patients who cannot tolerate semaglutide or tirzepatide for other reasons
- Where cost considerations favour Saxenda (depending on local pricing)
The future: oral tablets
The future of GLP-1 therapy is moving beyond injections entirely. Oral semaglutide is already available for type 2 diabetes (Rybelsus), and a higher-dose oral formulation for weight management is in late-stage clinical trials.
The OASIS 1 trial evaluated oral semaglutide 50 mg daily for weight loss, showing approximately 15 per cent weight loss over 68 weeks — comparable to injectable Wegovy. MHRA approval for a weight management oral semaglutide is expected to be considered in late 2026 or early 2027.
If approved, an oral tablet could eliminate the need for injections altogether, potentially improving adherence further and making GLP-1 therapy accessible to patients with needle phobia. However, oral semaglutide requires specific dosing conditions (taken on an empty stomach with a small amount of water, with no food for 30 minutes) that may affect convenience in practice.
How to choose: a decision framework
The choice between daily and weekly injections should be made with your prescriber based on your individual circumstances. Here are the key factors to consider:
- Weight loss goals: If maximising weight loss is the primary goal, weekly semaglutide or tirzepatide offer significantly greater efficacy
- Cardiovascular risk: If you have established cardiovascular disease, semaglutide (Wegovy) has proven cardiovascular benefits
- Convenience: Most patients prefer the simplicity of once-weekly dosing
- Tolerability: If gastrointestinal side effects are a concern, tirzepatide may have a milder profile
- Cost: Consider both NHS eligibility and private pricing for your situation
- Experience: If you have successfully used a daily injection and prefer it, that choice remains valid
Important: Never switch between GLP-1 medications without medical supervision. The dosing, escalation schedules and monitoring requirements differ between products. Always consult your prescriber before making a change.