Most comparisons declare a winner in the first paragraph. Here is what they tend to leave out: Wegovy tablets and Mounjaro have never been tested against each other in a clinical trial. What we have instead are separate trials, run in different groups of people over different lengths of time. They tell you a lot, but they do not tell you which medicine is better for you.
What are Wegovy tablets and Mounjaro?
Wegovy tablets contain semaglutide, a GLP-1 receptor agonist. It is the same active ingredient as the Wegovy injection, in a once-daily tablet. It is a different product from Rybelsus, the semaglutide tablet licensed for type 2 diabetes, and the two are not interchangeable. The MHRA licensed the tablet on 11 June 2026 and it became available on private prescription in the UK from July.
Mounjaro contains tirzepatide, given as a once-weekly injection from a pre-filled pen. Both medicines are licensed for weight management alongside a reduced-calorie diet and increased physical activity, for adults with a BMI of 30 or more, or 27 or more with a weight-related health condition. Both are prescription-only, and neither is intended as a short course.
How do they work?
Semaglutide copies a gut hormone called GLP-1. It tells your brain you are full, slows how quickly your stomach empties and helps you feel satisfied on smaller meals. Tirzepatide acts on two receptors rather than one, GLP-1 and GIP, which may explain the larger average loss seen in its trials.
Day to day the effect feels similar: less hunger, less food noise, fuller sooner. The differences you will actually notice are in the routine.
Daily tablet or weekly injection?
| Wegovy tablets | Mounjaro | |
|---|---|---|
| Active ingredient | Semaglutide (oral) | Tirzepatide |
| Receptors | GLP-1 | GLP-1 and GIP |
| Frequency | Once daily | Once weekly, same day |
| Timing rules | Empty stomach after 8 hours without food, sip of water only, then wait 30 minutes | Any time of day, with or without food |
| Dose ladder | 1.5mg, 4mg, 9mg, 25mg maintenance | 2.5mg to a maximum of 15mg |
| Storage | Room temperature, original packaging | Fridge 2-8°C until first use |
| Missed dose | Skip it, take the next one as normal | Take within 4 days, otherwise skip |
| NHS | Private only for now | Available in phases |
The tablet is swallowed whole with up to 120ml of water, about half a glass, after at least eight hours without food. Nothing else to eat or drink, and no other medicines, for at least 30 minutes afterwards. That means no coffee first thing and no just a biscuit, every day.
The routine matters because semaglutide is a peptide your stomach would normally digest. The tablet uses an absorption enhancer to get a small amount through, and anything else in your stomach gets in the way. Mounjaro asks for less discipline and a little more courage: one injection a week into the abdomen, thigh or upper arm, rotating the site each time.
What the trials found
| Trial | Treatment | Length | Average weight change |
|---|---|---|---|
| OASIS 4 | Wegovy tablet 25mg daily | 64 weeks | −13.6% overall, −16.6% among those who took it as intended (placebo −2.2%) |
| SURMOUNT-1 | Mounjaro 15mg weekly | 72 weeks | −20.9% (placebo −3.1%) |
| SURMOUNT-5 | Mounjaro vs the Wegovy injection | 72 weeks | −20.2% vs −13.7% |
| STEP 1 | Wegovy injection 2.4mg weekly | 68 weeks | −14.9% (placebo −2.4%) |
Three things stand out. The tablet’s result sits close to the injection form of the same medicine, which is what you would expect. Mounjaro’s advantage has been shown directly, but only against the Wegovy injection. And the averages hide a wide range: in OASIS 4 around 30% of people on the tablet lost 20% or more of their body weight, while others lost considerably less.
Side effects
Both medicines slow digestion and reduce appetite, so the common side effects are the same: nausea, vomiting, diarrhoea, constipation and stomach discomfort. They are usually mild to moderate, tend to appear around dose increases and generally settle as the body adjusts.
| Side effect | Proportion of trial participants |
|---|---|
| Nausea | 46.6% |
| Vomiting | 30.9% |
| Constipation | 20.1% |
| Diarrhoea | 17.6% |
| Altered skin sensation, such as tingling | About 5% |
| Hair loss | 6.4% |
In OASIS 4, gut-related side effects affected 74% of people on the tablet against 42% on placebo, but only around 7% stopped treatment because of them — similar to the placebo group.
For Mounjaro, nausea, diarrhoea, vomiting, constipation and abdominal pain are all listed as very common, with tiredness, dizziness, hair loss, injection-site reactions and gallstones listed as common. In SURMOUNT-1 roughly 4% to 7% of people stopped because of side effects, against about 3% on placebo. In the head-to-head against the Wegovy injection, slightly fewer people on Mounjaro stopped because of gut problems: 2.7% against 5.6%.
Storage and travel
The tablet needs no refrigeration. Keep it in its original packaging away from light and moisture and it will travel anywhere. Mounjaro pens are kept in the fridge between 2°C and 8°C until first use; once in use a pen can stay below 30°C for up to 30 days and is then discarded. Fine for most holidays, less convenient somewhere hot without reliable cooling.
Other medicines, contraception and pregnancy
- The contraceptive pill: Mounjaro can reduce how well it is absorbed. The leaflet advises a barrier method or non-oral contraception for four weeks after starting and four weeks after each dose increase.
- Other tablets: with Wegovy tablets, anything else oral waits at least 30 minutes. Levothyroxine exposure rose by about a third in studies, so thyroid levels may need monitoring, and warfarin means extra INR checks.
- Pregnancy: neither medicine should be used. Semaglutide is stopped at least two months before trying to conceive, tirzepatide at least one month.
- Breastfeeding: the tablet’s licence says semaglutide should not be used; tirzepatide’s says it could be considered.
Missed doses and switching
Miss a tablet and you skip it, then take your usual dose the next day. Never two. Miss a Mounjaro injection and you take it as soon as you remember if you are within four days, then carry on as normal; beyond four days you skip it and inject on your usual day, keeping at least three days between injections.
Switching between them is possible under medical supervision, never by taking both at once. There is no dose of one that equals a dose of the other, so you restart the new medicine at its lowest strength. The one exception sits within the same medicine: people established on the 2.4mg Wegovy injection can move straight to the 25mg tablet, seven days after their last injection.
NHS availability and private prescriptions
Mounjaro is available on the NHS, but in stages. NICE recommends tirzepatide for adults with a BMI of 35 or more and at least one weight-related condition, with lower thresholds for people from some ethnic backgrounds. NHS England began a phased rollout in June 2025, starting with a BMI of 40 or more and at least four qualifying conditions, and full coverage is expected to take years.
Wegovy tablets are private-only for now and will stay that way unless NICE assesses them. Privately, the licence criteria decide eligibility: a BMI of 30 or more, or 27 or more with a weight-related condition. Because both are prescription-only medicines, we do not publish prices in our guides.
Choosing between them
Rather than asking which is best, ask which one you will manage well month after month. Five questions usually get to the answer.
- Can I realistically fast for eight hours and wait 30 minutes every morning? If not, the tablet will be a daily battle.
- Do I take other morning medicines that cannot be moved? Thyroid tablets, for example, complicate the tablet routine.
- Do I have a reliable fridge at home and when I travel? If not, the pen becomes awkward.
- Am I on the contraceptive pill, and happy to add a barrier method during dose increases?
- Have I already tried semaglutide? If it did not do enough, that is a genuine reason to discuss tirzepatide.
Take your answers to a consultation. Your prescriber will weigh them alongside your BMI, your medical history and your blood tests, and explain which options are actually suitable for you.
When to speak to a clinician
Contact your prescriber promptly if vomiting or diarrhoea stops you keeping fluids down for more than a day, if you feel faint when you stand, or if a side effect has you thinking about stopping. Call 111, or 999 in an emergency, for severe and persistent stomach pain, signs of an allergic reaction such as facial swelling or difficulty breathing, or symptoms of low blood sugar if you also use insulin. Do not start, stop or change the dose of either medicine without speaking to a clinician first.
Check which treatment you are eligible forTwo minutes, no charge, reviewed by a prescriber.→
Questions people ask
Is Mounjaro better than the Wegovy tablet?▾
In trials Mounjaro produced the larger average weight loss, and its advantage over the Wegovy injection has been confirmed directly. It has not been compared with the tablet, though, and a daily tablet you take reliably will usually do more for you than a weekly injection you avoid.
Is the Wegovy tablet an easier version of Mounjaro?▾
No. It is a different medicine, and for many people it is not easier. The trade for avoiding needles is an eight-hour fast and a 30-minute wait every morning, every day.
Can I take the tablet with my morning coffee?▾
Not straight away. It is taken with a small sip of water only, up to about half a glass, followed by at least 30 minutes with nothing else to eat or drink and no other medicines.
Which one is available on the NHS?▾
Mounjaro, in phases that began in June 2025 for people with the highest clinical need. Wegovy tablets are private-only for now, pending a NICE assessment. The Wegovy injection is available through some NHS specialist weight-management services for a maximum of two years.
How much weight will I lose on each?▾
Trial averages are about 13.6% over 64 weeks on the 25mg tablet, or about 16.6% among people who took it as intended, and about 20.9% over 72 weeks on Mounjaro 15mg. Your own result depends on your starting point, your dose, how consistently you take the medicine and the changes you make alongside it.
Can I switch from one to the other?▾
Yes, under medical supervision, and never both at once. There is no equivalent dose between them, so you restart the new medicine at its lowest strength and build up over several weeks.
Does either affect my contraception?▾
Mounjaro can reduce absorption of the contraceptive pill because it slows stomach emptying. The leaflet advises a barrier method or non-oral contraception for four weeks after starting and for four weeks after each dose increase.
Do I need a fridge for Wegovy tablets?▾
No. Tablets are kept at room temperature in their original packaging, away from light and moisture. Only Mounjaro pens need refrigeration, between 2°C and 8°C until first use.
- Licensed by the MHRA in June 2026 for weight management in adults
- About 13.6% average weight loss over 64 weeks in OASIS 4
- No needles and no refrigeration
- Prescriber-led dose ladder, reviewed every four weeks
References
- Medicines and Healthcare products Regulatory Agency. Semaglutide tablets approved for weight management, 11 June 2026.
- Electronic Medicines Compendium. Wegovy tablets — Summary of Product Characteristics.
- Electronic Medicines Compendium. Mounjaro KwikPen — Summary of Product Characteristics.
- OASIS 4: oral semaglutide 25mg for weight management. N Engl J Med. 2025.
- Jastreboff AM, et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). N Engl J Med. 2022;387:205-216.
- SURMOUNT-5: tirzepatide versus semaglutide in obesity. N Engl J Med. 2025.
- Wilding JPH, et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). N Engl J Med. 2021;384:989-1002.
- NICE TA1026. Tirzepatide for managing overweight and obesity.
- NICE TA875. Semaglutide for managing overweight and obesity.
- NHS. Tirzepatide (Mounjaro).
- NHS. Semaglutide (Wegovy).
