Foundayo vs Mounjaro: Daily Tablet or Weekly Injection?
Different drug classes, different routes, very different evidence—and only one of them is available on the NHS. What you're actually trading, and for what.
Part of the Overweight and Obesity condition guide.
The headline: In their respective 72-week trials, tirzepatide at 15 mg produced roughly double the average weight loss of orforglipron at its highest dose. Foundayo's advantage is that it's a tablet—not that it works as well. Mounjaro is also available on the NHS under NICE TA1026; Foundayo isn't.
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This comparison is different from comparing two tablets. Foundayo (orforglipron) and Mounjaro (tirzepatide) are different classes of medicine, given by different routes, with substantially different evidence behind them—and only one of them is currently available on the NHS.
If you're weighing these two, the honest framing isn't "which is better" but "what am I trading, and for what."
| Foundayo | Mounjaro | |
|---|---|---|
| Active ingredient | Orforglipron | Tirzepatide |
| How it works | GLP-1 receptor agonist | Dual GIP and GLP-1 receptor agonist |
| Form | Daily tablet | Weekly injection (pre-filled pen) |
| Manufacturer | Eli Lilly | Eli Lilly |
| UK approval for weight management | 10 August 2026 | Licensed since 2023 |
| Doses | 0.8–17.2 mg daily | 2.5–15 mg weekly |
| Typical trial weight loss | ~11–12% at highest dose over 72 weeks | ~21–22.5% at 15 mg over 72 weeks |
| NHS availability | No | Yes, under NICE TA1026, phased |
| Storage | Room temperature | Refrigerated before first use |
Both are prescription-only medicines. This page is general information, not a recommendation.
The mechanism difference is real
Foundayo acts on the GLP-1 receptor alone. Mounjaro acts on two gut hormone receptors—GLP-1 and GIP (glucose-dependent insulinotropic polypeptide).
This isn't marketing. Dual agonism appears to be a genuine reason tirzepatide has produced larger average weight reductions than single-agonist GLP-1 medicines across trials. The two hormone pathways affect appetite, insulin secretion and fat metabolism through partly separate routes, and hitting both seems to do more than hitting one. Our guide to how Mounjaro works goes into the detail.
That matters for how you read the numbers below: the gap between these two medicines isn't simply a tablet-versus-injection artefact. It reflects a difference in what the drugs do.
Effectiveness: what the trials showed
These two medicines have never been compared head-to-head. The figures come from separate trials. That said, unusually for such comparisons, they are more alike than most—both ran for 72 weeks, both were placebo-controlled, both enrolled adults with obesity or overweight with a weight-related condition, and both were run by the same manufacturer. The comparison is still indirect, but it's less of a stretch than usual.
Foundayo — ATTAIN-1
3,127
Adults enrolled, over 72 weeks
−11.1%
At 17.2 mg (treatment-policy), vs −2.1% placebo; −12.4% under the efficacy estimand
71.5%
Lost at least 5% of body weight
Mounjaro — SURMOUNT-1
2,539
Adults enrolled, over 72 weeks
−20.9%
At 15 mg (treatment-regimen), vs −3.1% placebo; −22.5% under the efficacy estimand
39.7%
Lost at least 25% of body weight; 96% lost at least 5%
What this means
Comparing like-for-like estimands, tirzepatide produced roughly double the average weight loss of orforglipron in their respective trials. That's a large difference, and it's consistent across both estimands and across every weight-loss threshold measured.
This is worth being clear about, because a lot of coverage of new oral GLP-1s implies rough parity with injectables. On the published evidence, there's no parity. Foundayo's advantage is that it's a tablet—not that it works as well.
That said: averages aren't predictions. Some people lose a great deal on orforglipron and relatively little on tirzepatide. Response varies widely, and a medicine you take consistently will outperform one you don't.
Practical differences
Taking it
Foundayo
One tablet daily, any time, with or without food, no water restrictions, stored at room temperature. Nothing to learn, nothing to carry, nothing to refrigerate.
Mounjaro
One injection weekly using a pre-filled pen, into the abdomen, thigh or upper arm, rotating sites. Pens need refrigeration before first use. There's a short learning curve, and travel takes a little planning.
For people with a genuine needle phobia, this isn't a minor consideration—it can be the difference between starting treatment and not. For most others, weekly injecting turns out to be less of an obstacle than anticipated, and a weekly action is arguably easier to remember than a daily one.
Titration
| Foundayo | Mounjaro | |
|---|---|---|
| Starting dose | 0.8 mg daily | 2.5 mg weekly |
| Step interval | Minimum 30 days at each strength | Every 4 weeks as tolerated |
| Number of increases | Up to 5 | Up to 5 |
| Maximum | 17.2 mg daily | 15 mg weekly |
| Time to maximum | About 5 months minimum | About 5 months minimum |
Both escalate slowly, for the same reason: gastrointestinal side effects track with dose. See the Foundayo titration schedule and the Mounjaro dose schedule for the detail.
Side effects and shared class warnings
Both share the GLP-1 class profile, and the commonest effects for both are gastrointestinal—nausea, constipation, diarrhoea, vomiting—worst after each dose increase, easing with time. Mounjaro adds injection-site reactions.
Both carry a boxed warning for thyroid C-cell tumours and are contraindicated in anyone with a personal or family history of medullary thyroid carcinoma or with MEN 2 syndrome. Both carry warnings for pancreatitis, gallbladder disease, dehydration and acute kidney injury, hypoglycaemia when combined with insulin or a sulfonylurea, and worsening diabetic retinopathy. Both carry aspiration risk under anaesthesia—tell any surgeon, anaesthetist, endoscopist or dentist well before any procedure. Neither should be used in pregnancy, and they shouldn't be taken together.
Foundayo has specific CYP3A4 interactions: maximum 9 mg daily with a strong inhibitor, avoid strong inducers including St John's wort, and limit simvastatin to 20 mg daily. Both may reduce absorption of oral contraceptives—raise this specifically with your prescriber. Compare the full detail in the Foundayo safety guide and our guide to Mounjaro side effects.
The access difference, and it's the big one
This is where the practical decision often gets made, and it points the opposite way from convenience.
Mounjaro is available on the NHS
Under NICE TA1026, tirzepatide is recommended for adults with:
- a BMI of at least 35 kg/m²—or 32.5 kg/m² for people of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean background—and
- at least one weight-related condition, such as established cardiovascular disease, treated hypertension, dyslipidaemia, obstructive sleep apnoea or type 2 diabetes
Rollout is phased over several years through both specialist weight management services and primary care, with the earliest cohorts being those with the highest BMI and most comorbidities. Access has been prioritised rather than universal, so eligibility on paper doesn't mean immediate availability—but the pathway exists.
Foundayo is not available on the NHS
No NICE appraisal has concluded, and NHS funding can't be considered until one does. Access is by private prescription only, and no UK price had been confirmed at the time of writing—see Foundayo UK cost and access.
So the trade is sharper than it first appears. The tablet is more convenient to take but must be paid for privately; the injection is less convenient but may be free at the point of use if you meet the criteria and can access the pathway.
How to think about the choice
Mounjaro may suit you better if
Maximising weight loss is the priority, you meet the NICE criteria and can access the NHS pathway, cost is a significant factor, or you'd prefer a weekly action over a daily one.
Foundayo may suit you better if
You have a genuine needle phobia, you can't access NHS treatment and are paying privately either way, travel or storage makes refrigerated pens impractical, or a daily tablet fits your routine better.
Either way, both are licensed as an adjunct to a reduced-calorie diet and increased physical activity—the trial results describe the medicine plus lifestyle support, not the medicine alone.
The first question to ask a prescriber isn't which of these two is better, but whether you meet the NICE criteria for NHS tirzepatide. That answer reframes everything else.
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Order Foundayo →Frequently Asked Questions
Is Foundayo as effective as Mounjaro?
No, on current evidence. In their respective 72-week trials, tirzepatide at 15mg produced roughly double the average weight loss of orforglipron at its highest dose: around 20.9% against 11.1% on the comparable treatment-policy analysis. The two medicines have never been compared directly, but the gap is consistent across both estimands and every weight-loss threshold measured.
Why would anyone choose the tablet if the injection works better on average?
Needle phobia, travel, storage, personal preference, or simply that the medicine you will actually take every day beats the one you will not. Mounjaro pens need refrigeration before first use, which complicates travel, and for someone with a genuine needle phobia the choice can be between a tablet and no treatment at all. Effectiveness in a trial and effectiveness in your life are not the same measure.
Can I switch from Mounjaro to Foundayo?
That is a clinical decision for your prescriber, who will advise on timing and starting dose. The two should never be taken together, because both act on the GLP-1 receptor. Given the difference in average effect, switching from the injection to the tablet may mean accepting a smaller result in exchange for convenience, so it is worth being clear about why you are switching.
Do I still pay for Mounjaro on the NHS?
Where you meet the NICE TA1026 criteria and can access the pathway, tirzepatide is provided on NHS prescription subject to the normal prescription charges that apply to you. Rollout is phased over several years and access has been prioritised, with the earliest cohorts being those with the highest BMI and most weight-related conditions, so eligibility on paper does not mean immediate availability.
Can I get Foundayo on the NHS?
Not currently. A NICE technology appraisal would be needed before NHS funding could be considered, and none has concluded. Access to Foundayo in the UK is by private prescription only at present, following a consultation with a registered prescriber.
Do Foundayo and Mounjaro cause the same side effects?
Broadly, yes. Both are dominated by gastrointestinal effects such as nausea, constipation, diarrhoea and vomiting, which are worst after each dose increase and ease with time, and both share the same class warnings including the boxed warning about thyroid C-cell tumours. Mounjaro adds injection-site reactions, and Foundayo has specific CYP3A4 drug interactions that the injection does not.
What are the NICE criteria for tirzepatide on the NHS?
Under NICE TA1026, tirzepatide is recommended for adults with a BMI of at least 35, or at least 32.5 for people of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean background, together with at least one weight-related condition such as established cardiovascular disease, treated hypertension, dyslipidaemia, obstructive sleep apnoea or type 2 diabetes. Rollout is phased through both specialist weight management services and primary care.
Which is easier to fit into daily life?
Foundayo is a tablet taken once a day at any time, with or without food, and stored at room temperature, so there is nothing to learn and nothing to carry. Mounjaro is a weekly injection using a pre-filled pen, rotating between the abdomen, thigh and upper arm, with refrigeration needed before first use. Some people find a weekly action easier to remember than a daily one, so easier is not the same answer for everyone.
Tablet or injection, with Access Doctor
Access Doctor is a GPhC-registered UK online pharmacy supplying licensed weight management medicines by private prescription. Our consultation is free and reviewed by a pharmacist independent prescriber, who will discuss whether you may be eligible for NHS treatment before recommending a private option. There's no obligation to order.
Weight Loss · Rx
Foundayo (Orforglipron)
Once-daily GLP-1 tablet, room temperature storage, no injections and no fasting routine.
View product →Weight Loss · Rx
Wegovy Tablets
Oral semaglutide up to 25 mg, the other licensed tablet, taken fasted each morning.
View product →Compare tablets and injections side by side on our weight loss treatments page.
References
- Medicines and Healthcare products Regulatory Agency. UK first in Europe to authorise orforglipron for weight management and type 2 diabetes. 10 August 2026. gov.uk
- US Food and Drug Administration. FOUNDAYO (orforglipron) tablets — Prescribing Information. 2026. accessdata.fda.gov
- Eli Lilly and Company. SURMOUNT-1 results published in the New England Journal of Medicine. investor.lilly.com
- Eli Lilly and Company. Complete ATTAIN-1 results published in the New England Journal of Medicine. 2026. lilly.gcs-web.com
- NHS England. Interim commissioning guidance: NICE TA1026 tirzepatide. england.nhs.uk
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment. In a medical emergency, call 999.