Foundayo vs Zepbound — Daily Pill or Weekly Shot from Lilly

Your prescriber has put two Lilly names on the table. One is a small tablet you'd take every day, the other is a pen you'd use once a week. You're not sure whether to think about it as "pill versus shot" or "which works better", and the honest answer is that it's both. Here's how they compare, from their labels.

Are Foundayo and Zepbound the same medicine?

No. They're made by the same company, but they contain different molecules:

• Foundayo is orforglipron, a small-molecule medicine that activates the GLP-1 receptor. FDA approved on April 1, 2026.
• Zepbound is tirzepatide, a peptide that activates both the GIP and GLP-1 receptors.

Both are approved, with a reduced-calorie diet and more activity, to reduce excess body weight and keep it off in adults with obesity, or overweight plus a weight-related condition. Zepbound is also approved for moderate to severe obstructive sleep apnea in adults with obesity. Neither label recommends using them together.

What does a week look like on each?

Foundayo is one tablet every day, at any time, with or without food. There's no water limit or waiting period. The dose climbs from 0.8 mg in steps of at least 30 days.

Zepbound is one injection a week, on the same day. It starts at 2.5 mg for 4 weeks and climbs in 2.5 mg steps, at least 4 weeks apart, to a maintenance dose of 5, 10 or 15 mg.

Seven small moments a week, or one bigger one. Some people find a daily habit easier to keep; others prefer to think about their medicine once a week and then forget it.

What about storage and travel?

Foundayo is kept at room temperature, 68°F to 77°F, in its bottle. Zepbound pens and vials go in the fridge, though the label allows single-dose pens and vials to stay unrefrigerated, up to 86°F, for a total of 21 days. For frequent travelers, that difference can matter.

What happens if you miss a dose?

• Foundayo: take it as soon as possible, but never two tablets in one day. After 7 or more missed days in a row, the label says to restart at a lower dose.
• Zepbound: take it within 4 days of the missed dose; after that, skip it and take the next one on your usual day.

How did each do in its trials?

There's no head-to-head trial. Each label reports its own 72-week, placebo-controlled trials in adults without diabetes:

• Foundayo: −7.4%, −8.3% and −11.1% on 5.5, 9 and 17.2 mg, versus −2.1% on placebo.
• Zepbound: −15.0%, −19.5% and −20.9% on 5, 10 and 15 mg, versus −3.1% on placebo.

These trials enrolled different people at different times, so the numbers can't be lined up exactly. Results also varied widely within each group.

Lilly has also studied moving from one to the other. In ATTAIN-MAINTAIN, adults who had lost weight on tirzepatide switched to orforglipron or placebo for a year. On orforglipron, they kept an average of 74.7% of their earlier weight reduction, versus 49.2% on placebo. Our Foundayo vs tirzepatide page looks at that trial in more detail.

How do side effects compare?

Both labels list stomach side effects as the most common, mostly during dose increases: nausea, diarrhea, vomiting and constipation. Nausea was reported by 26% to 35% on Foundayo and 25% to 29% on Zepbound. Zepbound adds injection-site reactions; Foundayo, being a tablet, doesn't.

Both carry a boxed warning about thyroid C-cell tumors and similar warnings about pancreatitis, gallbladder problems, kidney injury from dehydration and severe stomach reactions. Both also advise a backup to birth control pills after starting and after each dose increase.

What we'd track

On either medicine, these are the notes we'd keep:

1. Every dose. A daily tick for Foundayo; the weekly shot, its day and its site for Zepbound.
2. Dose step and date. Both labels move in steps, and side effects cluster around them.
3. Missed doses. The rules differ, and 7 missed days in a row on Foundayo changes the plan.
4. Side effects, rated daily. To see whether they settle as each label describes.
5. Weight trend, weekly. Calmer than daily, and enough to see the direction.

Holt is built for both routines: daily pill reminders or weekly shot reminders, a Live Activity on your lock screen, injection-site rotation with a suggested next spot, side effects lined up against dose days, and a doctor-visit report. It's free to download, with an optional subscription. This page is written by the Holt team.

Track Foundayo or Zepbound in Holt