For the first time, people choosing a weight loss medicine from Eli Lilly can pick between a daily pill and a weekly injection. Foundayo (orforglipron) was approved in April 2026 as a once-daily pill that can be taken at any time, with or without food. Zepbound (tirzepatide) is a once-weekly injection that has been available since 2023. Both work on the body's appetite hormones, but they differ in how much weight people lose on average, how they are taken, what they cost, and what else they are approved for. This guide compares Foundayo and Zepbound side by side, explains who each may suit, and covers your options if neither is right for you.
Leaning toward the pill?
If your weight is only somewhat above the healthy range, you may be able to take orforglipron, the medicine in Foundayo, as part of a clinical study.
Foundayo vs Zepbound
How they work
Both medicines mimic gut hormones that the body releases after eating, which reduce appetite, help you feel full sooner, and slow how quickly food leaves the stomach. Foundayo acts on one of these hormone receptors, GLP-1. Zepbound acts on two, GLP-1 and GIP. Foundayo is also a different kind of molecule: it is a small molecule rather than a protein, which is why it can be taken as a pill without the strict food and water rules that some other oral weight loss medicines have.
Which works better for weight loss?
On average, people lost more weight on Zepbound in its main trial. In SURMOUNT-1, adults on the highest dose of Zepbound lost about 21 percent of their body weight over 72 weeks. In ATTAIN-1, adults on the highest dose of Foundayo lost about 11 percent over 72 weeks, around 27 pounds, compared with about 2 percent on placebo. These were separate trials with different participants, and the two medicines have not been compared head to head, so the numbers are a guide rather than a direct contest. Results also vary a great deal from person to person.
For many people, the more important question is which medicine they can take consistently. A pill that fits easily into daily life may suit someone who dislikes injections, while a once-weekly injection may suit someone who prefers not to think about a medicine every day.
Side effects
Both medicines most often cause digestive side effects, such as nausea, diarrhea, constipation, and vomiting, especially while the dose is being increased. These usually ease over time. Both carry the same type of warnings as other medicines in this family, including risks of pancreatitis, gallbladder problems, and a boxed warning about thyroid tumors based on animal studies, which is why neither is used by people with a personal or family history of medullary thyroid cancer.
Our guide covers Zepbound side effects week by week, with the numbers from its label.
Cost and coverage
Through Lilly's own pharmacy, LillyDirect, Foundayo starts at $149 a month for the lowest dose without insurance, and Zepbound starts at $299 a month for the starting dose, rising to $449 for higher doses when refills are on time. With commercial insurance that covers them, eligible people may pay much less. Coverage for weight loss medicines varies widely, so it is worth checking with your plan before you start.
Who qualifies?
Both Foundayo and Zepbound are approved for adults with obesity, or adults with overweight who also have a weight-related medical problem, such as high blood pressure or type 2 diabetes, used alongside a reduced-calorie diet and more physical activity. Zepbound is also approved for moderate to severe obstructive sleep apnea in adults with obesity; if sleep apnea is part of your picture, our guide to CPAP alternatives covers the other treatments too. The choice between the two is a conversation for you and your prescriber.
Switching between them
Some people move from one medicine to the other because of side effects, cost, or how well it is working. Switching is a prescriber decision, because doses do not translate directly from one medicine to the other. If your weight loss has stalled on Zepbound, our guide explains the most common reasons; if you are on semaglutide, see not losing weight on Ozempic or Wegovy.
If you are overweight but do not qualify for a prescription
Many people carry some extra weight and have early warning signs in their blood tests, but do not yet meet the criteria for a weight loss prescription. A large clinical study of orforglipron, the medicine in Foundayo, is designed for exactly this group. The study is enrolling adults with a BMI of 25 to 29.9 whose waist measures at least half their height, who have at least one early warning sign such as prediabetes, borderline high blood pressure, or borderline high cholesterol, and who have tried at least once to lose weight with diet and exercise. People who already have diabetes, high blood pressure, or high cholesterol, or who have taken a weight loss medicine in the past six months, are not eligible. In this study, every group receives orforglipron for at least part of the time, though some participants also receive a placebo during the study.
If your BMI is 30 or higher, a group of studies for adults with overweight or obesity is also enrolling, and newer medicines such as retatrutide and eloralintide are being tested in clinical trials. Our weight loss treatment trials page lists what is recruiting near you, and our guide covers all current obesity treatment options.
Applying takes about 5 minutes. Nothing is decided until you have gone through informed consent, and you can leave a study at any time.
Common questions
Is Foundayo as effective as Zepbound? On average, people lost less weight on Foundayo in its main trial, about 11 percent at the highest dose, than on Zepbound in its main trial, about 21 percent. The trials were separate, and individual results vary.
Is Foundayo a pill version of Zepbound? No. Both are made by Eli Lilly, but they are different medicines. Foundayo contains orforglipron and acts on the GLP-1 receptor; Zepbound contains tirzepatide and acts on GLP-1 and GIP receptors.
Do I have to take Foundayo on an empty stomach? No. Foundayo can be taken once a day at any time, with or without food and without water restrictions.
Which is cheaper, Foundayo or Zepbound? Without insurance, Foundayo starts at $149 a month for the lowest dose through LillyDirect, and Zepbound at $299 a month for the starting dose. Prices depend on the dose and change over time.
Can I switch from Zepbound to Foundayo? Some people do, for example to avoid injections. Doses do not convert directly, so switching should be planned with your prescriber.
Is Foundayo approved for sleep apnea? No. Zepbound is approved for moderate to severe obstructive sleep apnea in adults with obesity; Foundayo is approved for weight management.
Do weight loss trial participants get paid? Some studies offer compensation for time and travel, and study related care is typically provided at no cost to participants. Compensation varies by trial and is always described during the informed consent process before you agree to anything.