Foundayo and Mounjaro are different medications
Because the two medications come from the same company and treat the same conditions, many people assume Foundayo is a tablet form of Mounjaro.
There’s no tablet form of Mounjaro, though, and Foundayo doesn’t contain tirzepatide; we’ve covered the “Mounjaro pill” confusion separately in our guide to whether there’s a Mounjaro pill.
It helps to separate the three medications people most often mix up:
- Foundayo (orforglipron): a once-a-day tablet that mimics GLP-1. Approved in the UK in August 2026, and covered in full in our Foundayo guide.
- Mounjaro (tirzepatide): a once-a-week injection that mimics GLP-1 and GIP. Available in the UK since 2023.
- The Wegovy pill (oral semaglutide): the other weight-loss tablet, made by Novo Nordisk. It’s a different drug from both, with its own rules about taking it on an empty stomach.
| Feature |
Foundayo |
Mounjaro |
| Drug |
Orforglipron |
Tirzepatide |
| Drug class |
GLP-1 receptor agonist (a small molecule, not a peptide) |
Dual GIP and GLP-1 receptor agonist (a peptide) |
| How you take it |
A tablet once a day, at any time, with or without food |
An injection under the skin once a week |
| Average weight loss in trials |
11.2% over 72 weeks (ATTAIN-1, highest dose)2 |
20.9% over 72 weeks (SURMOUNT-1, 15 mg)1 |
| Time to the highest dose |
About 5 months, though any dose from 5.5 mg can be continued long term |
About 16 to 20 weeks |
| Most common side effects |
Nausea, vomiting, diarrhoea, constipation6 |
Nausea, diarrhoea, vomiting, constipation5 |
| UK status |
Available privately since 24th August 2026; not yet available on the NHS |
Available since 2023, privately and on the NHS through a phased rollout |
Why one is a tablet, and one is an injection
Mounjaro is a peptide drug, a chain of amino acids similar to the hormones it mimics.
Swallowed as a tablet, a peptide would be broken down in the stomach like the protein in food, so tirzepatide has to be injected under the skin, where most of the dose reaches the bloodstream slowly over the week.
Orforglipron is a small molecule rather than a peptide. It isn’t broken down in the stomach in the same way, so it can be absorbed like an ordinary tablet.2
Because orforglipron is a small molecule rather than a peptide, Foundayo doesn’t have the same food, water, or timing restrictions as the Wegovy pill.
The Wegovy pill contains a peptide (semaglutide), so you must take it on an empty stomach and wait 30 minutes before eating. You can take Foundayo at any time of day, with or without food.4
Foundayo mimics one gut hormone, while Mounjaro mimics two. Orforglipron mimics GLP-1, which slows how quickly the stomach empties, signals fullness to the brain, and quiets food noise (the constant, intrusive thoughts about food).
Tirzepatide mimics GLP-1 and a second gut hormone, GIP, which works alongside it to reduce appetite further and help the body manage blood sugar.5
The dual action of Mounjaro is likely the reason it leads to more weight loss than Foundayo, and any other GLP-1 medication on the market.
Foundayo doesn’t need refrigeration and may suit people who prefer a daily tablet to a weekly injection. Still, Mounjaro produces more weight loss on average and is often the first choice for individuals looking to maximise weight loss.
A fair comparison of weight loss in trials
Foundayo and Mounjaro haven’t been compared directly in the same trial. The best available evidence is each drug’s main Phase 3 trial (large human studies with thousands of participants). Both trials tested adults with obesity, or overweight with a weight-related condition, without type 2 diabetes, over 72 weeks.
In SURMOUNT-1, people taking Mounjaro lost an average of 15.0% of their body weight on the 5 mg dose, 19.5% on 10 mg, and 20.9% on 15 mg, compared with 3.1% on placebo.1
In ATTAIN-1, people taking Foundayo’s highest trial dose lost an average of 11.2% of their body weight, compared with 2.1% on placebo.2
This comparison is often quoted as 22.5% versus 11.1%. The figures were calculated differently, so comparing them directly overstates the difference.
The 22.5% is Mounjaro’s average weight loss among people who stayed on treatment for the full trial.1
The 11.1% is Foundayo’s most conservative figure, the average weight loss for all participants who joined the trial, including those who stopped taking the medication.6
It’s important to ensure we’re comparing the outcomes that measured the same thing. Among everyone who enrolled, average weight loss was 20.9% with Mounjaro and 11.2% with Foundayo. Among participants who stayed on treatment, it was 22.5% and 12.4%, respectively.1,2
We use the 20.9% and 11.2% figures throughout our guides because they reflect what tends to happen across a real-world group, rather than only among people who complete a full course.
Either way, Mounjaro seems to produce about 9 to 10 percentage points more average weight loss than Foundayo.
In SURMOUNT-1, 57% of people on the 15 mg dose lost at least 20% of their body weight, compared with 18.4% on Foundayo’s highest dose.1,2
Just over half of people on Foundayo’s highest dose lost at least 10%, and alongside the weight loss they saw improvements in waist size, blood pressure, triglycerides, and cholesterol.2
ATTAIN-1 tested orforglipron in an earlier formulation at doses up to 36 mg. The licensed tablet goes up to 17.2 mg, and at that dose the prescribing information reports an average weight loss of 11.1%, almost identical to the trial result.6
| Measure |
Mounjaro |
Foundayo |
| Average weight loss across everyone enrolled |
20.9% |
11.2% |
| Average weight loss among participants who stayed on treatment |
22.5% |
12.4% |
| Participants who lost at least 20% of their body weight |
57% |
18.4% |
| Trial length |
72 weeks |
72 weeks |
These figures come from separate trials rather than a direct comparison between Foundayo and Mounjaro.1,2
Side effects compared
The most common side effects are the same for both medications: nausea, vomiting, diarrhoea, and constipation. They usually appear as the dose increases and settle as the body adjusts to the drugs, and most cases in the trials were mild to moderate.1,2
In weight-management trials, nausea affected 26% to 35% of people taking Foundayo and 24.6% to 29% taking Mounjaro, depending on the dose.5,6
Vomiting affected up to 24% of people at Foundayo’s highest dose, compared with 4% on placebo.6
Mounjaro also causes vomiting, most often during dose increases, but its UK product information doesn’t report a pooled figure.5
In ATTAIN-1, 5.3% to 10.3% of participants stopped taking Foundayo because of side effects, depending on the dose. In SURMOUNT-1, 4.3% to 7.1% stopped taking Mounjaro for the same reason.1,2
Foundayo also lists hair loss as a common side effect. This is usually temporary and linked to losing weight too quickly rather than to the drug itself.6
Because Foundayo is absorbed and processed like an ordinary tablet, it has some drug interactions Mounjaro doesn’t:
- Simvastatin: the simvastatin dose should be halved when taken with Foundayo.8
- Some antibiotics, antifungals, and epilepsy medications: drugs that strongly slow the liver enzyme that clears orforglipron cap Foundayo’s dose at 9 mg, while drugs that strongly speed it up, including carbamazepine, phenytoin, rifampicin, and St John’s wort, should be avoided with it.6
- Oral contraceptives: this advice applies to both medications, not just Foundayo. On either drug, the guidance is to switch to a non-oral method or add a barrier method for around a month after starting and after each dose increase.5,6
Switching from Mounjaro to Foundayo
One trial tested switching from Mounjaro to Foundayo after participants’ weight loss had plateaued. It measured how much of their weight loss they maintained over the following year.3
In ATTAIN-MAINTAIN, 376 people who had finished 72 weeks on either Mounjaro or Wegovy injections were switched to daily Foundayo or to a placebo tablet for a year.
Participants who switched from Mounjaro to Foundayo maintained 74.7% of their previous weight loss, compared with 49.2% among those switched to placebo.
Participants who switched from Wegovy to Foundayo maintained 79.3% of their weight loss, compared with 37.6% among those who switched to placebo.3
Still, it’s important to be aware that the trial compared switching to Foundayo with switching to placebo. It didn’t compare Foundayo with continuing Mounjaro.3
There’s also no official guidance on switching from Mounjaro to Foundayo.
The MHRA supported switching between the Wegovy injection and the Wegovy pill, but those are two forms of the same drug, semaglutide.
Foundayo and Mounjaro are different drugs, and there’s no established dose conversion between them. The UK Foundayo prescribing information starts treatment at 0.8 mg and doesn’t give a different starting dose for people switching from Mounjaro.8
So if Mounjaro is working for you and you’re tolerating it, there’s no obvious clinical reason to switch while you’re still losing weight.
Foundayo may be an option for maintaining weight loss after Mounjaro once weight has plateaued.
A tablet may also suit people who dislike injections or need medication that doesn’t require refrigeration. We explain the evidence in more detail in our guide to oral medications for weight maintenance.
Appetite and food noise can gradually return once a GLP-1 medication leaves the system. In ATTAIN-MAINTAIN, participants who stopped Mounjaro and switched to placebo regained about half of their previous weight loss within a year.3
Weight regain isn’t inevitable, and it depends largely on whether time on medication built sustainable eating habits.
Weight regain is much more likely when the medication is stopped suddenly (compared to a gradual titration), and if the individual hasn’t developed a healthier lifestyle to manage hunger and cravings without the drug.
Cost and availability in the UK
Mounjaro has been available in the UK since 2023. On a private prescription, it costs from around £129 to £179 a month at the starting doses, rising to about £329 or more at the 15 mg dose. It’s also prescribed on the NHS through a phased rollout for people meeting specific criteria.
Foundayo became available on private prescription in the UK on 24th August 2026.
Through Second Nature, the first month at 0.8 mg costs £54 on the 12-month plan or £79 on the flexible monthly plan. Both prices include a £50 introductory discount.
After the first month, the 12-month plan costs £104 a month for 0.8 mg, 2.5 mg, or 5.5 mg, £124 for 9 mg, and £154 for 14.5 mg or 17.2 mg.
The flexible plan costs £129, £149, and £179 a month across the same dose bands. Our guide to how much Foundayo costs in the UK explains the full pricing schedule.
NICE (the body that decides which medications the NHS funds) is already appraising Foundayo for weight management, with guidance expected on 18th November 2026. Until then, it’s available on private prescription only; our guide to Foundayo and the NHS explains this in more detail.
Which might suit you
If the priority is the largest average weight loss, then Mounjaro is the obvious choice. No other GLP-1 medication matches the average weight loss of Mounjaro.1,2
However, for individuals who don’t like needles, Foundayo is a good option and still supports significant weight loss. You can take it any time of day, with or without food and water.
For individuals currently on Mounjaro or Wegovy injections who want to switch to a pill for weight maintenance, Foundayo is also a reasonable option, as evidence suggests it can help to maintain most of the weight lost.3
If you take simvastatin, certain epilepsy medications, or St John’s wort, tell your prescriber before considering Foundayo, because the interactions above may mean you need to stay at a lower dose or that you’re not able to take Foundayo at all.
Frequently asked questions
Is Foundayo the same as Mounjaro?
No. Foundayo is orforglipron, a once-a-day tablet that mimics the appetite hormone GLP-1.
Mounjaro is tirzepatide, a once-a-week injection that mimics two hormones, GLP-1 and GIP. Both are made by Eli Lilly, but they’re different drugs.
Is Foundayo a form of tirzepatide?
No. Foundayo contains orforglipron, a small-molecule GLP-1 drug. Tirzepatide is only available as an injection, sold as Mounjaro in the UK and as Zepbound in the U.S. for weight loss.
Is Foundayo as good as Mounjaro for weight loss?
No. Compared on the same basis, Mounjaro produced an average weight loss of 20.9% at its highest dose in trials, and Foundayo 11.2%.1,2 Just over half of the people on Foundayo’s highest dose still lost at least 10% of their body weight.2
Can you take Foundayo and Mounjaro together?
No. Foundayo’s prescribing information advises against combining it with any other GLP-1 medication, and Mounjaro acts on the same GLP-1 receptor.6 Taking both would add side effects without evidence of extra benefit.
How do I switch from Mounjaro to Foundayo?
You’d make the switch through your prescriber. There’s no official dose-conversion guide, and the UK Foundayo prescribing information starts treatment at 0.8 mg, including after another weight-loss medication.8
Is Foundayo cheaper than Mounjaro?
Yes. Through Second Nature, Foundayo is cheaper at every corresponding stage of the six-step dose schedule.
On the flexible monthly plan, Foundayo costs £129 to £179 a month, compared with £229 to £349 for Mounjaro. Foundayo is between 44% and 55% cheaper at each stage, and 49% cheaper on average.
On the 12-month plan, Foundayo costs £104 to £154 a month, compared with £204 to £324 for Mounjaro. Foundayo is between 49% and 61% cheaper at each stage, and 54% cheaper on average.
These are the ongoing prices after the first month. The comparison matches the same stage of each medication’s dose schedule; the doses themselves aren’t clinically equivalent.
Can you get Foundayo on the NHS?
It’s not available on the NHS yet. Foundayo is licensed in the UK, but on private prescription only for now. NICE guidance on NHS funding for weight management is expected on 18th November 2026.
Does Foundayo have food or water restrictions like the Wegovy pill?
No. You can take Foundayo at any time of day, with or without food or water.4
The Wegovy pill needs to be taken on an empty stomach because it’s less effective if you don’t. We’ve compared the two tablets in our Wegovy pill vs Foundayo guide.
What happens if I miss a dose of Foundayo?
Take the missed tablet as soon as possible, but don’t take more than one tablet in a day. Continue with the usual schedule afterwards.8
Take home message
Foundayo and Mounjaro aren’t the same medication, and Foundayo isn’t a tablet form of Mounjaro. Foundayo is a daily tablet that mimics one appetite hormone; Mounjaro is a weekly injection that mimics two.
When researchers included everyone who enrolled in each trial, average weight loss was 20.9% with Mounjaro and 11.2% with Foundayo.
Among participants who stayed on treatment, the figures were 22.5% and 12.4%. Comparing Mounjaro’s 22.5% result with Foundayo’s 11.1% result combines figures calculated differently and overstates the difference.
Foundayo is worth considering if you don’t like injections. It’s a once-a-day tablet with no food or timing rules, and you can keep it at room temperature.
If Mounjaro is working for you, there’s no obvious clinical reason to switch. Switching to Foundayo when you’ve reached your weight loss goal is an option, but even then that comes with risks, as you don’t know if your body will respond well to the drug. In this scenario, staying on a lower dose of Mounjaro for maintenance may be a better option.
Whichever medication you take, they should always be combined with healthy lifestyle changes to improve overall health and wellbeing and help to prevent weight regain in the future.
Second Nature’s programme combines medication support with personalised nutrition guidance from registered dietitians and nutritionists, built around a balanced plate of vegetables, protein, complex carbohydrates, and healthy fats.
A peer-reviewed study published in JMIR Formative Research found that active subscribers on Second Nature’s semaglutide-supported programme lost an average of 19.1% of their body weight at 12 months, with 77.7% achieving at least 10% weight loss.7
Second Nature's Mounjaro and Wegovy programmes
Second Nature provides Mounjaro or Wegovy as part of our Mounjaro and Wegovy weight-loss programmes.
Why choose Second Nature over other medication providers, assuming you're eligible?
Because peace of mind matters.
We've had the privilege of working with the NHS for over eight years, helping people across the UK take meaningful steps toward a healthier, happier life.
Our programmes are designed to meet people where they are, whether that means support with weight loss through compassionate one-to-one health coaching, or access to the latest weight-loss medications (like Mounjaro and Wegovy) delivered alongside expert care from a multidisciplinary team of doctors, psychologists, dietitians, and personal trainers.
At the heart of everything we do is a simple belief: real, lasting change comes from building better habits, not relying on quick fixes. We're here to support that change every step of the way.
With over a decade of experience, thousands of lives changed, and a long-standing record of delivering programmes used by the NHS, we believe we're the UK's most trusted weight-loss programme.
We hope to offer you something invaluable: peace of mind, and the support you need to take that first step.
