Foundayo vs Mounjaro: Tablet vs Injection From the Same Company
Foundayo is a daily orforglipron tablet that activates the GLP-1 receptor. Mounjaro is a weekly tirzepatide injection that activates both GIP and GLP-1 receptors. Neither requires fasting. Their separate 72-week trials reported overall average weight loss of 11.2% and 20.9% at the highest studied doses, respectively. These are not head-to-head results and do not predict your personal response. Both treatments require clinical assessment and prescriber approval.
Foundayo vs Tirzepatide: What Is the Difference?
Comparing Foundayo vs tirzepatide means comparing Foundayo’s active ingredient, orforglipron, with the active ingredient in Mounjaro. Tirzepatide is the medicine name and Mounjaro is its brand name; they are not separate treatment options.
Mounjaro contains tirzepatide, which activates GIP and GLP-1 receptors involved in appetite and blood-glucose regulation. It is supplied as a weekly injection. Its effects and dose schedule cannot be inferred from another GLP-1 medicine.
Foundayo contains orforglipron, a non-peptide GLP-1 receptor agonist supplied as a daily tablet. It has no food or water restrictions. Although both medicines come from Lilly, Foundayo is not an oral version of Mounjaro and the doses are not interchangeable. Our weight loss pills vs injections guide explains how daily routines, storage and administration differ across the available formats.
| Foundayo | Mounjaro | |
|---|---|---|
| Manufacturer | Eli Lilly | Eli Lilly |
| Format | Daily tablet | Weekly injection |
| Active ingredient | Orforglipron (small molecule) | Tirzepatide (peptide) |
| Mechanism | GLP-1 receptor agonist only | Dual GIP + GLP-1 receptor agonist |
| Food/water restriction | None — any time of day | None — no timing restriction around meals |
It's important to be upfront here: Foundayo and Mounjaro haven't been tested against each other in a head-to-head trial, so any comparison below is between two separate trials with different designs and populations — not a controlled, direct comparison.
| Foundayo (ATTAIN-1) | Mounjaro (SURMOUNT-1) | |
|---|---|---|
| Trial duration | 72 weeks | 72 weeks |
| Average weight loss: overall analysis | 11.2% (36 mg trial capsule, equivalent to 17.2 mg tablet) | 20.9% (15 mg weekly) |
| Estimate assuming treatment continued | 12.4% | 22.5% |
| Placebo weight loss: overall analysis | 2.1% | 3.1% |
The main row uses the treatment-regimen analysis from each trial, which estimates outcomes regardless of treatment discontinuation. The second row gives the separate efficacy analysis, assuming treatment continued. These are separate trials in adults without type 2 diabetes, with different populations and study designs. They cannot establish which medicine will work better for an individual. All treatments were studied alongside diet and physical activity. Both medicines also have UK indications for type 2 diabetes, but diabetes studies should not be substituted for these weight-management results.
For more detail on the tablet evidence, see our Foundayo before and after guide. If you are comparing oral options, our Foundayo vs Wegovy pill guide covers the two tablet treatments. To compare Mounjaro with oral semaglutide instead, read our Wegovy pill vs Mounjaro guide.
| Foundayo | Mounjaro | |
|---|---|---|
| Starting dose | 0.8mg | 2.5mg |
| Dose levels, including starting dose | 6 | 6 |
| Minimum time per step | 30 days | 28 days (4 weeks) |
| Maximum dose | 17.2mg | 15mg |
Foundayo starts at 0.8 mg daily and progresses through 2.5, 5.5, 9, 14.5 and 17.2 mg, with at least 30 days before each increase. Mounjaro starts at 2.5 mg weekly for four weeks, then 5 mg; any further increases are in 2.5 mg steps after at least four weeks. Its adult maintenance doses are 5, 10 or 15 mg. Neither schedule means everyone needs the maximum. See our Foundayo dosage guide and Mounjaro dose schedule guide.
Side Effects ComparedBoth can cause nausea, diarrhoea, vomiting, constipation and indigestion, especially during dose increases. A dual-receptor mechanism alone does not establish that Mounjaro causes worse early side effects than Foundayo. Tolerability needs to be assessed for the individual.
Important
Never combine Foundayo and Mounjaro, or take either alongside another GLP-1 receptor agonist medicine. If you're considering switching between them, your prescriber should determine the starting dose and timing; do not overlap treatments or choose a switching interval yourself.
Mounjaro KwikPens are refrigerated at 2–8°C before use. After first use, they may be kept at no more than 30°C for up to 30 days and must then be discarded. Foundayo does not need refrigeration, but must remain in its original packaging to protect it from light. Follow the leaflet supplied with your medicine when storing or travelling with it.
Neither Foundayo nor Mounjaro currently has a specific UK indication for cardiovascular risk reduction. The Wegovy injection has this indication for eligible adults with established cardiovascular disease and overweight or obesity. Discuss cardiovascular needs with your prescriber rather than assuming all weight-loss medicines offer the same protection.
A Genuinely Different Choice From the Same CompanyA daily tablet and a weekly injection offer different routines. The choice should also account for medical history, interactions, tolerability, response and cost. Sharing a manufacturer does not make the medicines equivalent, and a trial average is only one part of the discussion.
Prices and Pack Sizes at Happy PharmacyFoundayo pill prices range from £94.49 on subscription or £104.99 as a single purchase at 0.8 mg, to £175.49 or £194.99 respectively at 17.2 mg. Each pack contains 30 tablets for 30 days of once-daily treatment.
Before you buy Mounjaro online, compare the price at the strength prescribed for you. At the prices listed here, 2.5 mg starts at £134.99 on subscription or £149.99 as a single purchase; 15 mg costs £287.99 or £319.99 respectively. Each pen contains four weekly doses for 28 days of treatment.
Happy Pharmacy prices checked 1 October 2026 and subject to change. Compare the same purchase option and pack duration, and check delivery options and any charges at checkout. Consultation is free. The doses shown illustrate pricing; your prescriber decides which medicine and dose are suitable. Twelve 30-day tablet packs cover 360 days; thirteen 28-day injection packs cover 364 days.
Which Might Suit You BetterFoundayo may suit you if…
- You have needle anxiety or would simply prefer never to self-inject
- You want a treatment with no fasting or food-timing requirement at all
- You want to discuss an oral option with a prescriber — Foundayo is available to order now
Mounjaro may suit you if…
- Your prescriber considers tirzepatide suitable for your medical history and treatment goals
- You're comfortable with a weekly injection rather than a daily tablet
- You'd prefer Mounjaro weight loss injections, a medicine with a longer UK real-world track record
A change needs a prescriber-led plan: the starting dose and timing depend on your current medicine, dose, response and side effects. Do not overlap treatments or calculate your own equivalent dose. ATTAIN-MAINTAIN studied selected patients who had completed an injection trial. Switching to orforglipron preserved more of their earlier weight loss than switching to placebo, but some weight regain occurred. This does not guarantee that someone switching in routine care will keep all their previous weight loss.
Both Available Now — Find the Right One for You
Foundayo tablets and Mounjaro injections are available through Happy Pharmacy following a free online consultation and prescriber approval. Your assessment helps determine whether treatment is suitable.
Weight loss medications Use code SWITCH10 if you're switching from another providerHappy Pharmacy is a GPhC-registered pharmacy (No. 9012585) — Superintendent Pharmacist: Palvinder Deol — Rated 4.8★ Excellent on Trustpilot