Compare weight loss treatments
Every treatment we prescribe is MHRA licensed for weight management and supplied by a Pharmacy details to be confirmed. Your prescriber recommends the option suited to your history, preferences and goals.
 Mounjaro |  Wegovy |  Wegovy pill |  Foundayo pill | |
|---|---|---|---|---|
| Active ingredient | Tirzepatide | Semaglutide | Oral semaglutide | Orforglipron |
| Works on | GLP-1 and GIP receptors | GLP-1 receptor | GLP-1 receptor | GLP-1 receptor (non-peptide) |
| How you take the medicine | One injection a week, any time of day | One injection a week, any time of day | One tablet each morning, empty stomach, up to 120 ml water, wait 30 minutes | One tablet a day, any time, with or without food |
| Dose range | 2.5 mg to 15 mg | 0.25 mg to 7.2 mg | 1.5 mg to 25 mg | 0.8 mg to 17.2 mg |
| Dose steps | 6 doses, at least 4 weeks each | 6 doses, at least 4 weeks each | 4 doses, at least 1 month each | 6 strengths, at least 30 days each |
| Average loss in the main trial | 20.9%15 mg, SURMOUNT-1, 72 weeks, 2,539 participants | 14.9%2.4 mg, STEP 1, 68 weeks, 1,961 participants | 13.6%25 mg, OASIS 4, 64 weeks, 307 participants | 11.2%17.2 mg, ATTAIN-1, 72 weeks, 3,127 participants |
| Placebo group in the same trial | 3.1% | 2.4% | 2.2% | 2.1% |
| People who lost 10% or more | 83.5% | 69.1% | 59.8% | 54.6% |
| People who lost 15% or more | 70.6% | 50.5% | 47% | 36% |
| Other trial evidence | SURMOUNT-5: 20.2% loss against 13.7% for semaglutide at 72 weeks | SELECT: 20% lower risk of major heart events in adults with heart disease. STEP UP: 18.7% loss on 7.2 mg | Same molecule as the Wegovy pen, which has the SELECT heart outcome data | ATTAIN-MAINTAIN: kept 74.7% of earlier loss after switching from tirzepatide |
| Most common side effect | Nausea, 28% of people on the top dose | Nausea, 43.9% of people on the top dose | Nausea, 46.6% of people on the top dose | Nausea, 33.7% of people on the top dose |
| The contraceptive pill | Can reduce the effect. Use a barrier method for 4 weeks after starting and after each dose increase | No clinically relevant effect reported | No clinically relevant effect reported | Can reduce the effect. Follow the leaflet on barrier or non-oral methods |
| Storage | Fridge, 2 to 8°C. Up to 30 days below 30°C once in use | Fridge, 2 to 8°C before first use. 6 weeks below 30°C once in use | No special temperature. Keep in the blister | Keep in the original pack, away from light |
| Missed dose | Take within 4 days, then skip | Take within 5 days, then skip | Skip, take the next tablet tomorrow | Take when you remember. One tablet a day at most |
| Stop before a planned pregnancy | At least 1 month | At least 2 months | At least 2 months | At least 3 weeks |
| On the NHS | Limited, phased access | Specialist services only | Not available | Not available |
| Price at Aero Clinic | To be confirmed | To be confirmed | To be confirmed | To be confirmed |
| Medicine and dose | Trial | Average loss | Placebo |
|---|---|---|---|
| Mounjaro 15 mg | SURMOUNT-1, 72 weeks | 20.9% | 3.1% |
| Wegovy 2.4 mg | STEP 1, 68 weeks | 14.9% | 2.4% |
| Wegovy pill 25 mg | OASIS 4, 64 weeks | 13.6% | 2.2% |
| Foundayo pill 17.2 mg | ATTAIN-1, 72 weeks | 11.2% | 2.1% |
Each bar counts every participant in the trial, including people who stopped treatment early. All trials ran alongside diet and activity support. These are four separate trials, so the bars give context and do not rank the medicines. In SURMOUNT-5, the one direct comparison, tirzepatide averaged 20.2% and semaglutide 13.7% at 72 weeks. See the evidence for each medicine.
What usually decides the choice
Biggest average loss
Mounjaro has the highest trial average, 20.9% on 15 mg. Wegovy 7.2 mg averaged 18.7% in STEP UP.
Needle-free
The Wegovy pill and Foundayo are daily tablets. Foundayo has no fasting rules. The Wegovy pill is taken on an empty stomach with a short wait before breakfast.
Longest track record
Semaglutide (Wegovy) has the most published safety data in this group, including a large cardiovascular outcomes trial.
Lowest monthly cost
See the price list for every dose. Aero’s prices are not yet confirmed.
The contraceptive pill
Mounjaro can reduce absorption of the contraceptive pill at dose changes. Foundayo carries a similar warning. If the pill is your method, Wegovy or the Wegovy pill may suit better.
Your history decides
Reflux, gallbladder problems, diabetes medicines and past pancreatitis all shape the recommendation. The health check covers each one.
The four plans
MounjaroTirzepatide, 2.5 mg to 15 mg
Prices to be confirmed
20.9% average weight loss on 15 mg in the SURMOUNT-1 trial at 72 weeks
- Works on two appetite hormones, GLP-1 and GIP
- One pen holds four weekly doses
- Six dose steps, raised only when you are ready
WegovySemaglutide, 0.25 mg to 7.2 mg
Prices to be confirmed
14.9% average weight loss on 2.4 mg in the STEP 1 trial at 68 weeks
- Works on the GLP-1 appetite hormone
- Longest safety record in this group of medicines
- Lowest starting price of the four plans
Wegovy pillOral semaglutide, 1.5 mg to 25 mg
Prices to be confirmed
13.6% average weight loss on 25 mg in the OASIS 4 trial at 64 weeks
- Same medicine as the Wegovy pen, with no needle
- One tablet each morning on an empty stomach
- Stores at room temperature
Foundayo pillOrforglipron, 0.8 mg to 17.2 mg
Prices to be confirmed
11.2% average weight loss on the top dose in the ATTAIN-1 trial at 72 weeks
- Once-daily GLP-1 tablet with no needle
- No food or water rules around your dose
- Stores at room temperature
Saxenda, Nevolat and orlistat
Daily liraglutide (Saxenda, or generic Nevolat) and orlistat capsules are older licensed treatments. They cost less and produce smaller average losses, around 8% for liraglutide and 5 to 10% over a year for orlistat. We prescribe them when a weekly pen or daily GLP-1 tablet is unsuitable.
Guides in this series
Page information
- Summary
- Compare weight-management medicine guides by ingredient, routine and evidence. Discuss benefits, risks and suitability with a qualified prescriber.
- Publisher
- Aero Clinic, operated by AERO HEALTHCARE LTD.
- Editorial update
- Clinical review
- Pending. An editorial update is not a clinical sign-off.
Cite as: Compare weight loss treatments, Aero Clinic (https://www.cagri.co.uk), AERO HEALTHCARE LTD. https://www.cagri.co.uk/treatments. Editorial update: 4 November 2026. Clinical review pending.