Eli Lilly's incretin lineup is built around tirzepatide, which it sells as Mounjaro for type 2 diabetes and Zepbound for obesity, alongside its older GLP-1 injection Trulicity. Its pipeline adds the oral pill orforglipron (approved in April 2026 as Foundayo) and the experimental triple agonist retatrutide, still in trials.
What GLP-1 drugs does Eli Lilly currently sell?
Lilly markets three injectable incretin medicines in the United States. Two of them share the same molecule, tirzepatide, and one is a pure GLP-1 agonist.
Mounjaro (tirzepatide) — type 2 diabetes
Mounjaro is a once-weekly injection that the FDA approved on May 13, 2022 to improve blood sugar in adults with type 2 diabetes, alongside diet and exercise (Lilly). It is not approved for weight loss, even though weight reduction is a common effect. For a full breakdown of dosing and use, see our Mounjaro guide.
Zepbound (tirzepatide) — obesity and sleep apnea
Zepbound is the same tirzepatide molecule, branded and dosed for chronic weight management. The FDA approved it on November 8, 2023 for adults with obesity, or overweight with a weight-related condition. In December 2024 it became the first drug approved for moderate-to-severe obstructive sleep apnea in adults with obesity, based on the SURMOUNT-OSA trial (Lilly). Our Zepbound guide covers titration and cost in detail.
Trulicity (dulaglutide) — the original Lilly GLP-1
Trulicity is Lilly's older, once-weekly GLP-1 receptor agonist, approved in 2014 for type 2 diabetes and later to reduce cardiovascular risk. It is a pure GLP-1 drug (no GIP activity) and produces more modest weight loss than tirzepatide. See the Trulicity guide for how it compares.
How is tirzepatide different from a pure GLP-1 drug?
Tirzepatide is a dual agonist: it activates both the GLP-1 receptor and the GIP (glucose-dependent insulinotropic polypeptide) receptor. Most older drugs in this class, including Trulicity, Ozempic and Wegovy, act on GLP-1 alone.
Adding GIP activity appears to amplify appetite reduction and metabolic benefit, which is why tirzepatide produced larger average weight loss than semaglutide in head-to-head trials. We unpack the molecular differences in tirzepatide vs semaglutide.
What is orforglipron (Foundayo), Lilly's GLP-1 pill?
Orforglipron is a small-molecule oral GLP-1 agonist — a pill rather than a peptide injection. Because it is not a peptide, it can be taken without the strict fasting and water rules that apply to Novo Nordisk's oral semaglutide.
The FDA approved orforglipron as Foundayo on April 1, 2026 for adults with obesity or overweight with a weight-related condition. In the ATTAIN-1 trial, participants lost up to roughly 12.4% of body weight at 72 weeks (Lilly). Like injectable incretins, it carries a boxed warning about thyroid C-cell tumors. If you are pricing it out, see our notes on the Foundayo coupon.
What is retatrutide, and when could it launch?
Retatrutide is Lilly's investigational triple agonist, hitting the GLP-1, GIP and glucagon receptors at once. The glucagon arm is thought to increase energy expenditure on top of appetite suppression.
In May 2026, Lilly reported topline results from TRIUMPH-1, its first Phase 3 obesity trial: participants on the 12 mg dose lost an average of about 28.3% of body weight at 80 weeks (Lilly). Additional TRIUMPH readouts in diabetes and cardiovascular disease are expected through 2026, so an FDA filing is most likely in late 2026 or 2027, with approval no earlier than 2027. It is not approved or commercially available yet — anything sold today is research-grade. Our retatrutide overview and orforglipron vs retatrutide comparison go deeper.
Eli Lilly GLP-1 product comparison
| Product | Molecule | Receptors | Indication | Form | Status |
|---|---|---|---|---|---|
| Mounjaro | Tirzepatide | GLP-1 + GIP | Type 2 diabetes | Weekly injection | Approved (2022) |
| Zepbound | Tirzepatide | GLP-1 + GIP | Obesity; OSA | Weekly injection | Approved (2023) |
| Trulicity | Dulaglutide | GLP-1 | Type 2 diabetes; CV risk | Weekly injection | Approved (2014) |
| Foundayo | Orforglipron | GLP-1 (oral) | Obesity | Daily pill | Approved (2026) |
| Retatrutide | Retatrutide | GLP-1 + GIP + glucagon | Obesity (investigational) | Weekly injection | Phase 3 |
How do you choose between Lilly's options?
The right Lilly drug depends on your diagnosis and goal. Mounjaro is prescribed for type 2 diabetes; Zepbound is the obesity and sleep-apnea label for the same molecule; Trulicity is an older diabetes choice. Foundayo is the new oral option for people who prefer a pill over an injection, while retatrutide remains experimental. Insurance coverage, not just efficacy, often decides the outcome — compare real prices in our cheapest GLP-1 roundup. This is a conversation to have with a prescriber, not a decision to make alone.
How effective are Mounjaro and Zepbound?
Tirzepatide set new benchmarks for the class. In the SURMOUNT-1 obesity trial, adults without diabetes lost an average of about 20.9% of body weight on the highest 15 mg dose over 72 weeks — well above what earlier GLP-1 drugs achieved. In the SURPASS diabetes program, Mounjaro produced large reductions in A1C alongside meaningful weight loss. Those results are why tirzepatide became one of the most prescribed metabolic drugs in the US. Individual results vary widely with dose, diet and consistency; see tirzepatide dosing for how titration works.
What side effects do Lilly's GLP-1 drugs cause?
The most common side effects of tirzepatide and orforglipron are gastrointestinal — nausea, diarrhea, vomiting, constipation and reduced appetite — usually worst when starting or increasing the dose, and often eased by slower titration. Like all incretin drugs, they carry a boxed warning about the risk of thyroid C-cell tumors and should be avoided by anyone with a personal or family history of medullary thyroid carcinoma or MEN 2. Rarer but serious risks include pancreatitis and gallbladder problems. Always review the FDA-approved label and your prescriber's guidance before starting.
How much do Eli Lilly's GLP-1 drugs cost?
List prices for Mounjaro and Zepbound run into four figures per month before insurance, though coverage, savings cards, and Lilly's self-pay vial program through LillyDirect can lower out-of-pocket costs substantially. Foundayo, as an oral option, is positioned to broaden access further. Actual prices change frequently, so compare current numbers in our cheapest GLP-1 guide rather than relying on a fixed figure.
Did Eli Lilly make other GLP-1 drugs?
Yes. Lilly was an early player in the class through exenatide — sold as Byetta and the weekly Bydureon — which it co-developed and marketed years before tirzepatide; those rights later moved to AstraZeneca. That early experience helped position Lilly for the dual- and triple-agonist drugs it leads with today.
How are Lilly's GLP-1 drugs taken?
Mounjaro and Zepbound are once-weekly subcutaneous injections, given on the same day each week in the abdomen, thigh or upper arm, with or without food. Both start at a low dose (2.5 mg) and step up gradually over months to limit gastrointestinal side effects, which is why patients should not jump to a high dose. Trulicity is also a weekly injection. Foundayo, by contrast, is a once-daily tablet that can be taken at any time, with no fasting or water restrictions — its main practical advantage over peptide-based pills. Whichever option you use, follow the titration schedule on the label and from your prescriber rather than escalating on your own; our tirzepatide dosing guide walks through the typical steps.
Frequently Asked Questions
Is Mounjaro the same as Zepbound?
Yes — both are tirzepatide. Mounjaro is the brand approved for type 2 diabetes, and Zepbound is the brand approved for weight management and obstructive sleep apnea. The active ingredient and dosing strengths are the same.
Does Eli Lilly make Ozempic or Wegovy?
No. Ozempic and Wegovy are semaglutide products made by Novo Nordisk. Lilly's competing molecules are tirzepatide (Mounjaro and Zepbound) and the pill orforglipron (Foundayo).
Is retatrutide available to buy yet?
No. Retatrutide is still in Phase 3 trials and has not been approved by the FDA. Products marketed online as retatrutide are unapproved research chemicals and are not quality-assured for human use.
What is the difference between tirzepatide and a GLP-1 drug?
Tirzepatide is a dual GLP-1 and GIP receptor agonist, while drugs like Trulicity, Ozempic and Wegovy act on the GLP-1 receptor alone. The added GIP activity is associated with greater average weight loss.
This article is for educational purposes and is not medical advice. Talk to a licensed healthcare professional before starting, stopping, or changing any medication.
