Orforglipron (Foundayo) Side Effects: What the FDA Label Says

Quick answer

As of September 2026, the most common orforglipron side effects named on the FDA-approved label for Foundayo, a once-daily GLP-1 receptor agonist tablet with "Initial U.S. Approval: 2026", are, in the label's order: nausea, constipation, diarrhea, vomiting, dyspepsia (indigestion), abdominal pain, headache, abdominal distension (bloating), fatigue, eructation (belching), gastroesophageal reflux disease, flatulence, and hair loss. The same label carries one boxed warning about thyroid C-cell tumors, two contraindications, and nine Warnings and Precautions categories. Whether orforglipron is safe for you depends on your history, your other medicines, and a physician's judgment; the sections below follow the order patients usually ask.

Who should not take orforglipron at all?

The label lists two contraindications:

• "A personal or family history of MTC or in patients with MEN 2." MTC is medullary thyroid carcinoma, a rare thyroid cancer; MEN 2 is an inherited syndrome that raises its risk.
• "Known serious hypersensitivity to orforglipron or any of the excipients in FOUNDAYO." Excipients are the inactive ingredients.

Separately, the label names groups for whom Foundayo is "not recommended" rather than forbidden outright: it "is not recommended in patients with severe gastroparesis" (a stomach that empties very slowly), "is not recommended for use in patients with severe hepatic impairment" (advanced liver disease), and "is not recommended for nursing women." Under Limitations of Use, "Concomitant use with another GLP-1 receptor agonist is not recommended," and "Safety and effectiveness of FOUNDAYO have not been established in pediatric patients."

What does the boxed warning mean in plain words?

A boxed warning is the strongest warning on a prescription label. Foundayo carries one titled "WARNING: RISK OF THYROID C-CELL TUMORS." In medicines with GLP-1 receptor activity that work in rats and mice, the label explains, "rodent thyroid C-cell tumors (adenomas and carcinomas) have been observed at clinically relevant exposures."

Orforglipron itself is unusual here: "Orforglipron is not pharmacologically active in rats or mice and did not produce tumors in rodents." Still, "the human relevance of GLP-1 receptor-dependent thyroid C-cell tumors observed in rodents has not been determined." The warning is carried over from the drug class, and whether it matters for people remains an open question.

What to watch for, in the label's words: "a mass in the neck, dysphagia, dyspnea, or persistent hoarseness," meaning a lump in the neck, trouble swallowing, shortness of breath, or a hoarse voice that does not go away.

What are the most common orforglipron side effects?

The label's list, quoted in the quick answer, is dominated by digestive symptoms, plus headache, fatigue, and hair loss. Section 6.1 of the label gives the percentage for each reaction; we do not reproduce trial percentages here, so read that section for the numbers. The label gives no timeline for how long they last.

The gradual dose increases exist "to reduce the risk of gastrointestinal (GI) adverse reactions," which is why a physician will not rush the schedule. And patients are told "to contact their healthcare provider if they have severe or persistent gastrointestinal symptoms." Vomiting that will not stop is something to report now, because of the kidney warning below. Our guide on how to read a prescription label shows where each section lives.

Which serious side effects does the label warn about?

The Warnings and Precautions section has nine numbered categories.

1. Thyroid C-cell tumors. Covered above under the boxed warning.

2. Acute pancreatitis. "Acute pancreatitis has been reported in patients treated with FOUNDAYO." Watch for "persistent or severe abdominal pain (sometimes radiating to the back) and which may or may not be accompanied by nausea or vomiting." If suspected, stop the medicine and seek care.

3. Severe gastrointestinal reactions. "Use of FOUNDAYO has been associated with gastrointestinal adverse reactions, sometimes severe." This is the category behind the gastroparesis restriction.

4. Acute kidney injury from dehydration. The label reports "acute kidney injury, in some cases requiring hemodialysis," mostly in patients "who experienced gastrointestinal adverse reactions leading to dehydration such as nausea, vomiting, or diarrhea." If you cannot keep fluids down, that is a medical problem.

5. Hypoglycemia (low blood sugar). "FOUNDAYO lowers blood glucose and can cause hypoglycemia." The risk is highest with certain diabetes medicines: "Concomitant use with insulin or an insulin secretagogue may increase the risk of hypoglycemia, including severe hypoglycemia."

6. Hypersensitivity reactions. "Serious hypersensitivity reactions (e.g., anaphylaxis, angioedema) have been reported with GLP-1 receptor agonists." If a hypersensitivity reaction occurs, the label's instruction is to stop the medicine and promptly seek medical attention.

7. Diabetic retinopathy complications. For people with type 2 diabetes: "Temporary worsening of diabetic retinopathy has been reported with rapid improvement in glucose control." The label asks physicians to monitor anyone with a history of retinopathy.

8. Acute gallbladder disease. "Treatment with FOUNDAYO and GLP-1 receptor agonists is associated with an increased occurrence of acute gallbladder disease." The Medication Guide tells patients to report pain in the upper abdomen, fever, yellowing of the skin or eyes, or clay-colored stools right away.

9. Pulmonary aspiration during anesthesia or deep sedation. Because the medicine slows stomach emptying, it "may lead to complications with anesthesia or deep sedation during planned surgeries or procedures." Patients are told to "inform healthcare providers prior to any planned surgeries or procedures."

Does orforglipron interact with other medicines?

Yes. The label names:

• Strong CYP3A4 inhibitors, medicines that slow the liver enzyme that clears orforglipron. The label sets a lower maximum dose in this situation and says to "Avoid concomitant use of FOUNDAYO with strong CYP3A4 inhibitors that also inhibit OATP1B (e.g., ritonavir)."
• Strong CYP3A4 inducers, which speed up that enzyme and can make orforglipron less effective. The label says to avoid them and to monitor effectiveness with moderate inducers.
• Simvastatin, a cholesterol medicine. The label caps the simvastatin dose that may be used alongside Foundayo because the combination "increased exposure of the active metabolite simvastatin acid two-fold."
• Insulin and insulin secretagogues such as sulfonylureas, because of the hypoglycemia risk; the label says to "consider reducing the dose" of those medicines.
• Any oral medicine. "FOUNDAYO delays gastric emptying and thereby has the potential to impact the absorption of concomitantly administered oral medications."

What if I am pregnant, breastfeeding, or using birth control pills?

The label is direct: "Weight loss offers no benefit to a pregnant patient and may cause fetal harm. When a pregnancy is recognized, advise the pregnant patient of the risk to a fetus and discontinue FOUNDAYO." For breastfeeding, "FOUNDAYO is not recommended for nursing women."

Birth control pills get their own instruction because the tablet slows stomach emptying. The label advises "patients using oral hormonal contraceptives to switch to a non-oral contraceptive method or add a barrier method of contraception for 30 days after initiation with FOUNDAYO and for 30 days after each dose escalation." Non-oral methods "should not be affected."

Who should talk to a physician before taking it?

Based on the label, a physician needs to know about:

• Any personal or family history of thyroid cancer, or MEN 2
• A prior serious allergic reaction to any GLP-1 medicine
• Pancreatitis, gallbladder disease, or gallstones
• Type 2 diabetes, especially with insulin or a sulfonylurea, or diabetic eye disease
• Kidney problems, severe liver disease, or gastroparesis
• Pregnancy, plans for pregnancy, or breastfeeding
• Any planned surgery or procedure with sedation
• Every medicine and supplement you take, including birth control pills, statins, and any medicine that affects the CYP3A4 liver enzyme (the label names ritonavir, an HIV medicine, as an example)

Apart from the two contraindications, none of these automatically rules the medicine out; they change the conversation and sometimes the monitoring.

What is Foundayo (orforglipron)?

Foundayo is the brand name for orforglipron, a GLP-1 receptor agonist made by Eli Lilly and Company. According to Lilly's announcement, the FDA "approved Foundayo (orforglipron) for adults with obesity, or overweight with weight-related medical problems" on April 1, 2026. The DailyMed label carries "Initial U.S. Approval: 2026," with the current version published August 13, 2026. It is indicated "in combination with a reduced-calorie diet and increased physical activity" for adults with obesity, or overweight with a weight-related condition. For how the class works, see what a GLP-1 medication is.

How is Foundayo taken, according to the label?

The instructions are short: "Take FOUNDAYO orally once daily, with or without food. Swallow tablets whole. Do not break, crush, or chew. Do not take more than one tablet per day." Lilly's patient page adds that you should "Protect Foundayo from light and keep in the original bottle and carton."

The label describes a stepwise dose schedule "based on treatment response and tolerability." The strengths and schedule belong in the conversation with your prescriber.

On missed doses: "If a dose is missed, instruct patients to take the dose as soon as possible. Advise patients not to double up the next dose." The label gives a separate instruction for a longer run of missed doses, so discuss any long gap with a physician rather than restarting alone.

How does an oral GLP-1 compare with injectable GLP-1 medicines?

Only on route and schedule, because the Foundayo label itself cautions that adverse reaction rates from one drug's trials "cannot be directly compared to rates in the clinical trials of another drug."

Foundayo is a tablet swallowed once a day. Injectable GLP-1 medicines such as Zepbound and Wegovy are given under the skin on the schedule in their own labels. Tirzepatide has no approved tablet at all, and whether an oral tirzepatide exists explains what the products sold under that name are. The oral route is what creates the contraceptive and CYP3A4 notes above; the injectables carry their own overlapping warnings, covered in our Zepbound side effects guide. See also oral and sublingual GLP-1 forms and Wegovy alternatives.

Where do compounded GLP-1 products fit?

Orforglipron is not a compounded product. It is an FDA-approved, manufacturer-made tablet. Compounded medications are not FDA-approved as final products. The FDA states: "Compounded drugs are not FDA-approved. This means that FDA does not verify the safety, effectiveness or quality of compounded drugs before they are marketed."

Federal law also limits what a compounding pharmacy may make. Under section 503A of the Federal Food, Drug, and Cosmetic Act, a pharmacy relying on that exemption "does not compound regularly or in inordinate amounts (as defined by the Secretary) any drug products that are essentially copies of a commercially available drug product." A compounding pharmacy may not copy an approved product like Foundayo except within the narrow allowances the law provides. Compounded GLP-1 products are a different category, explained in is compounded semaglutide FDA-approved.

What does Foundayo (orforglipron) cost?

As of September 2026, TrumpRx.gov lists Foundayo as an out-of-pocket option fulfilled through LillyDirect, with the price varying by tablet strength and some prices temporarily reduced through December 31, 2026. Lilly's April 1, 2026 approval announcement described a self-pay starting price for the lowest dose and lower amounts for some people with commercial coverage or Medicare Part D; that statement is older than September 2026, so this article does not repeat it as a current price. Prices change; check LillyDirect, TrumpRx.gov, and your coverage.

Questions to bring to a physician

• Do either of the contraindications or any of the "not recommended" groups apply to me?
• Which of my current medicines interact with orforglipron, and does anything need adjusting first?
• I use birth control pills. What should I switch to or add, and for how long?
• What symptoms mean "call today" versus "mention at the next visit"?
• I have a procedure scheduled. What should I tell the anesthesia team?
• If I miss several days, how do we restart?

The help center answers common questions about physician review and what happens if a physician does not prescribe.

This article is for informational purposes only and does not constitute medical advice. Do not start, stop, or change any medication based on this page. Always read the full FDA-approved label and Medication Guide for Foundayo and discuss your personal risk with a physician.