Orforglipron

The GLP-1 injections are like a key cut to fit the appetite lock. Orforglipron is a different-shaped key, made of different material, that turns the same lock. It is easier to carry around (a pill, not a pen), but it opens the door a little less wide than the best injections do.

Binds and activates the GLP-1 receptor (a class B G-protein-coupled receptor) despite being a small non-peptide molecule. This enhances glucose-dependent insulin release, suppresses glucagon, slows gastric emptying and reduces appetite through central GLP-1 signalling. Being a small molecule, it is absorbed from an ordinary tablet without the food and water restrictions of oral semaglutide.

Research contexts. Not proven uses, and not recommendations.

Strong and published. ATTAIN-1 (NEJM 2025, n=3,127) showed about 11.2% mean weight loss at the highest dose over 72 weeks versus 2.1% on placebo; 54.6% of people on the top dose lost 10% or more of their weight, versus 12.9% on placebo. ATTAIN-2 (Lancet, n=1,613) showed up to about 9.6% weight loss versus 2.5% in people with type 2 diabetes. ACHIEVE-1 (NEJM 2025, n=559) showed clear blood-sugar improvements in early type 2 diabetes. Gastrointestinal side effects were the most common and mostly mild to moderate, but more people stopped treatment because of side effects than on placebo. All the pivotal trials were funded by Eli Lilly, and the longest published trials ran for 72 weeks.

• !Common gastrointestinal side effects (nausea, vomiting, diarrhoea, constipation, indigestion, abdominal pain), mostly during dose increases; 5.3-10.3% stopped treatment for side effects in ATTAIN-1 versus 2.7% on placebo
• !Acute pancreatitis and gallbladder disease are listed warnings, as with other GLP-1 medicines
• !Carries the GLP-1 class boxed warning for thyroid C-cell tumours in the US, although orforglipron itself did not cause these tumours in rodents. Contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2
• !May reduce the reliability of the oral contraceptive pill when starting and after each dose increase; the label advises a non-oral or backup method at those times
• !May cause harm in pregnancy; the label says to stop it when pregnancy is recognised
• !Average weight loss is smaller than with injectable semaglutide or tirzepatide
• !Long-term data are limited compared with older GLP-1 medicines; the published trials run up to 72 weeks and were all sponsor-funded
• !GREY MARKET: the MHRA warns that buying GLP-1 medicines from unregulated sellers carries serious health risks. Anything sold without a prescription is unlicensed and of unknown content

Licensed UK medicine, prescription-only (POM). The MHRA authorised orforglipron as Foundayo (Eli Lilly) on 10 August 2026, the first authorisation in Europe, for weight management in adults with a BMI of 30 or more, or 27 to 30 with at least one weight-related condition, alongside diet and activity, and for type 2 diabetes that is not well controlled. It is available only on prescription through regulated pharmacies. It is not currently available on the NHS: NHS use depends on a NICE evaluation that had not concluded at the time of writing. Material sold online as 'orforglipron' without a prescription is unlicensed and outside regulatory oversight.

• NCT05869903· Phase 3· Active, not recruiting (primary results published)

  ATTAIN-1: Orforglipron in adults with obesity or overweight with weight-related comorbidities

  3,127 participants; 72-week primary endpoint; about 11.2% mean weight loss at the top dose.

• NCT05872620· Phase 3· Completed

  ATTAIN-2: Orforglipron in adults with obesity or overweight and type 2 diabetes

  1,613 participants; up to about 9.6% weight loss vs 2.5% placebo at 72 weeks.

• NCT05971940· Phase 3· Completed

  ACHIEVE-1: Orforglipron in type 2 diabetes inadequately controlled with diet and exercise

  559 participants; significant HbA1c reduction vs placebo at 40 weeks.

1. 01
   Orforglipron, an Oral Small-Molecule GLP-1 Receptor Agonist for Obesity Treatment (ATTAIN-1) — Wharton S, et al., New England Journal of Medicine (2025)

   Pivotal obesity trial, n=3,127; about 11.2% mean weight loss at the top dose vs 2.1% placebo at 72 weeks.

2. 02
   Orforglipron, an oral small-molecule GLP-1 receptor agonist, for the treatment of obesity in people with type 2 diabetes (ATTAIN-2) — Horn DB, et al., The Lancet (2025)

   n=1,613 with obesity and type 2 diabetes; up to about 9.6% weight loss vs 2.5% placebo at 72 weeks. Epub November 2025.

3. 03
   Orforglipron, an Oral Small-Molecule GLP-1 Receptor Agonist, in Early Type 2 Diabetes (ACHIEVE-1) — Rosenstock J, et al., New England Journal of Medicine (2025)

   n=559; HbA1c and weight reductions vs placebo over 40 weeks.

4. 04
   UK first in Europe to authorise orforglipron for weight management and type 2 diabetes, MHRA / GOV.UK (2026)

   MHRA authorisation of Foundayo on 10 August 2026; indications, prescription-only, not yet on the NHS pending NICE.

5. 05
   FOUNDAYO (orforglipron) tablets: US prescribing information, US FDA (2026)

   Boxed warning wording (no rodent tumours with orforglipron), warnings, pregnancy and oral contraceptive advice.

6. 06
   World Anti-Doping Code International Standard: Prohibited List 2026, World Anti-Doping Agency (2026)

   GLP-1 receptor agonists are not listed; S0 covers only substances without regulatory approval.