Foundayo (orforglipron) and Mounjaro (tirzepatide) are both prescription weight-management medicines, but they work and are taken very differently: Foundayo is a once-daily oral GLP-1 pill taken any time of day, while Mounjaro is a weekly self-injection that acts on two gut-hormone receptors. This article explains those differences factually so you can understand the options — a decision that is always made with a GPhC-registered prescriber.
Before going further, one important point about availability. Mounjaro is available through our service now. Foundayo received a UK marketing authorisation on 10 August 2026, but we do not supply it yet; we intend to offer it once we are able to obtain it. A marketing authorisation means a medicine is permitted to be prescribed in the UK — it does not mean any particular pharmacy stocks it.
The quick comparison
| Feature | Foundayo (orforglipron) | Mounjaro (tirzepatide) |
|---|---|---|
| Type | Small-molecule GLP-1 receptor agonist | Dual GLP-1 and GIP receptor agonist |
| Form | Once-daily oral tablet | Once-weekly injection |
| Timing | Any time of day, with or without food or water | Weekly, on the same day each week |
| Maximum licensed dose | 36mg | 15mg |
| Trial weight change (highest dose) | 12.4% over 72 weeks (ATTAIN-1) | 22.5% over 72 weeks (SURMOUNT-1) |
| Availability with us | Not supplied yet; we intend to offer it once we can obtain it | Available now after consultation |
How each medicine works
Mounjaro activates two gut-hormone receptors at once — GLP-1 and GIP. GLP-1 helps you feel fuller sooner and for longer and slows how quickly the stomach empties; adding GIP is a second, complementary pathway involved in appetite and how the body handles energy.
Foundayo is a single-target GLP-1 receptor agonist. What makes it notable is its chemistry: it is a small molecule designed to survive digestion, so it can be taken as an ordinary tablet rather than an injection. This is why it can be swallowed at any time of day, with or without food or water.
Because Mounjaro engages two receptors and Foundayo one, they are structurally different classes of medicine — not simply the same drug in two formats.
How you take them
Mounjaro is a weekly injection. You start on a 2.5mg starter dose and step up gradually — 5mg, 7.5mg, 10mg, 12.5mg — to a maximum licensed dose of 15mg. Titrating slowly helps your body adjust and can reduce side effects.
Foundayo is a once-daily pill titrated from a lower starting dose up to a licensed maximum of 36mg. Its practical appeal is flexibility: no injection technique, no cold-chain storage worries, and no fixed timing rule.
It is worth noting how Foundayo differs from the oral Wegovy Tablet (oral semaglutide). The Wegovy Tablet must be taken first thing on an empty stomach with a small sip of plain water, then you wait at least 30 minutes before eating, drinking or taking other medicines. Foundayo has no such restriction. If you are weighing up oral options, that difference matters.
What the trials showed
In the SURMOUNT-1 trial, participants on the Mounjaro 15mg dose lost on average 22.5% of body weight over 72 weeks, alongside lifestyle support. Individual results vary; not everyone reaches this.
In the Phase 3 ATTAIN-1 trial, participants on the Foundayo 36mg dose lost on average 12.4% of their body weight over 72 weeks, alongside lifestyle counselling. Individual results vary; not everyone reaches this.
These figures come from separate trials with different participants and designs, so they are not a head-to-head comparison. Comparing percentages between two unrelated studies can be misleading, and the numbers alone cannot tell you which medicine suits you. Suitability depends on your health, your preferences, and a prescriber's clinical judgement.
Side effects
Both medicines act on the GLP-1 pathway, so they share a broadly similar side-effect profile. The most common effects (more than 1 in 10 people) include nausea, diarrhoea, constipation, vomiting, decreased appetite and fatigue. These are often most noticeable when starting or increasing a dose and tend to settle over time.
Rare but serious risks associated with this class include severe allergic reaction, acute pancreatitis, severe hypoglycaemia (particularly if combined with certain diabetes medicines), severe gastrointestinal disease, and — for people with diabetes — worsening diabetic retinopathy. Seek medical advice promptly if you experience severe or persistent symptoms.
If you experience a side effect from any medicine, you can report it through the MHRA Yellow Card scheme at https://yellowcard.mhra.gov.uk/.
Who these medicines are for
Eligibility criteria are consistent across our weight-management treatments. In general you may be considered if you are aged 18 or over and have a BMI of 30 or above, or a BMI of 27–30 with a weight-related condition such as type 2 diabetes, high blood pressure or sleep apnoea.
These medicines are not suitable for everyone. They are generally not appropriate if you are pregnant, planning pregnancy or breastfeeding; have type 1 diabetes; have a personal or family history of medullary thyroid carcinoma or MEN2; have a history of pancreatitis; have severe gastrointestinal disease, an active eating disorder, or severe liver or kidney impairment; or are allergic to the active ingredient.
Cost
Mounjaro pricing depends on the dose, starting at £160 per month for the 2.5mg dose. You can see the full dose-by-dose pricing on the Mounjaro page.
There is no published UK price for Foundayo, and no confirmed NICE timetable for possible NHS funding — NHS funding is a separate decision from the MHRA licence. Rather than estimate, we will publish accurate pricing if and when we are able to supply it.
How to find the right option
The most useful next step is a clinical assessment rather than a pros-and-cons list. Our free online consultation is reviewed by a GPhC-registered independent prescriber who checks whether a treatment is clinically appropriate and safe for you. A prescription is only issued if suitable — treatment is never guaranteed.
You can also explore all our treatments, compare the weight-loss injections, or read more on the blog. To understand how our regulated UK pharmacy service works, see our about page.
This article is for information only and is not a substitute for personalised medical advice. Weight-loss medicines are prescription-only, are not suitable for everyone, and are prescribed only after a clinical consultation with a GPhC-registered prescriber. Individual results vary. Always speak to a UK-registered pharmacist or doctor before starting or changing any prescription medication.
