Foundayo Side Effects

A comprehensive guide to what you might experience while taking Foundayo (fown-DAY-oh), orforglipron. Available as a Pen or Vial, Foundayo is a once-weekly injection. Understanding potential side effects helps you prepare and manage your treatment effectively.

Boxed Warning: Thyroid C-Cell Tumors

WARNING: In animal studies, GLP-1 receptor agonists caused thyroid tumors, including thyroid cancer. It is not known if Foundayo causes thyroid tumors or cancer in people. Do not use Foundayo if you or any of your family members have had medullary thyroid carcinoma (MTC) or if you have Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).

Common Side Effects

Most patients experience some gastrointestinal side effects, particularly during the dose escalation phase. These often improve as your body adjusts to each dose level. Here are the most frequently reported side effects:

Nausea

The most common side effect, especially during dose escalation. Nausea typically improves significantly over the first few weeks at each new dose level as your body adjusts.

Constipation

Reduced digestive activity as your body adjusts to Foundayo. Staying hydrated and consuming adequate fiber can help manage this symptom.

Diarrhea

Some patients experience diarrhea, which can alternate with constipation. This usually resolves as your body adapts to the medication.

Vomiting

More likely during dose increases. Eating smaller meals and staying hydrated can help reduce the likelihood and severity of vomiting.

Indigestion/Dyspepsia

A feeling of fullness, bloating, or discomfort after eating. This typically decreases as your digestive system adjusts.

Stomach/Abdominal Pain

Usually mild to moderate pain or cramping. If pain is severe or persistent, contact your healthcare provider immediately.

Headache

Some patients report headaches, especially early in treatment. These often improve over time.

Fatigue

Tiredness or low energy levels. Ensure adequate rest and nutrition to help manage this side effect.

Belching

Related to digestive effects of the medication. Eating slowly and chewing thoroughly may help reduce this symptom.

Heartburn/GERD

Acid reflux or burning sensation in the chest. Avoid fatty and spicy foods, and avoid eating close to bedtime.

Gas/Flatulence

Excess gas during digestive adjustment. This symptom typically decreases over time as your body adapts.

Hair Loss

Some patients report hair loss during weight loss, thought to be related to rapid weight change and nutritional demands rather than the medication itself.

Swollen Belly

Abdominal bloating or swelling can occur during the digestive adjustment period. This symptom typically resolves as your body adapts to the medication.

Serious Side Effects

While uncommon, some serious side effects can occur. Seek immediate medical attention if you experience any of the following:

Pancreatitis

Inflammation of the pancreas requiring immediate medical attention. Stop taking Foundayo and call your doctor immediately if you experience severe abdominal pain that won't go away, with or without vomiting.

Gallbladder Problems & Gallstones

Rapid weight loss can increase gallstone risk. Seek immediate care if you experience severe pain in the upper right or center of your abdomen, fever, or yellowing of the skin and eyes.

Hypoglycemia (Low Blood Sugar)

Increased risk, especially if taking other diabetes medications. Symptoms include dizziness, blurred vision, difficulty concentrating, sweating, fast heartbeat, shakiness, and weakness. Always carry glucose tablets or juice.

Kidney Problems

Dehydration from vomiting or diarrhea can cause kidney damage. Stay well-hydrated and contact your doctor if you experience decreased urination or swelling in legs/feet.

Serious Allergic Reactions

Seek emergency care if you experience swelling of the face, lips, tongue, or throat; difficulty breathing; rash; or fainting. These are signs of a severe allergic reaction requiring immediate medical attention.

Vision Changes

Patients with type 2 diabetes may experience changes in vision, including diabetic retinopathy. Report any vision changes to your eye care provider immediately.

Gastroparesis (Stomach Paralysis)

A severe condition where the stomach cannot empty properly. Symptoms include severe nausea, vomiting, abdominal pain, and feeling unusually full. Seek immediate medical attention if you suspect this condition.

Surgery & Anesthesia Warning

Important: Tell your healthcare provider if you are planning to have surgery. Foundayo may increase the risk of food or liquid getting into your lungs during anesthesia (aspiration). Your provider may ask you to stop Foundayo before a scheduled surgery. Be sure to discuss your Foundayo use with your surgical team and anesthesiologist.

Tips for Managing Side Effects

Start low, go slow: Gradual dose escalation is key. Your body needs time to adjust at each dose level.
Eat smaller meals more frequently: Instead of three large meals, try five or six smaller meals throughout the day to reduce nausea and digestive upset.
Stay hydrated: Drink plenty of water throughout the day, especially important if experiencing vomiting or diarrhea. Dehydration can worsen side effects and damage your kidneys.
Avoid fatty or spicy foods: These can trigger or worsen nausea, indigestion, and other GI symptoms while you're adjusting.
Take it at a consistent time: While Foundayo works any time of day, taking it at the same time helps your body establish a routine.
Side effects often improve with time: Most patients find that side effects decrease significantly after the first few weeks at each new dose level.
Ensure adequate nutrition: Maintain proper protein and nutrient intake to support your health during weight loss and help minimize hair loss.

If You Miss a Dose

If you miss a dose of Foundayo, take it as soon as you remember on the same day. However, if 7 or more days have passed since your last dose, do not take the missed dose. Instead, contact your healthcare provider before restarting—they may need to adjust your dosing schedule to ensure your safety and treatment effectiveness.

Who Should Not Take Foundayo

Foundayo is not appropriate for everyone. Do not take Foundayo if you have any of the following:

Personal or family history of medullary thyroid carcinoma (MTC)
Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)
Serious allergic reaction to orforglipron or any ingredients in Foundayo
Currently pregnant or planning to become pregnant
Currently breastfeeding

Drug Interactions

Foundayo may interact with other medications. Inform your healthcare provider about all medications and supplements you're taking:

Other GLP-1 Medications

Do not use Foundayo if you're taking other GLP-1 receptor agonists (such as Wegovy, Ozempic, or Mounjaro). Using multiple GLP-1 medications together is not recommended.

Oral Birth Control

Foundayo may reduce the effectiveness of oral contraceptives. Use backup contraception for at least 30 days after starting Foundayo and for 30 days after each dose increase.

Diabetes Medications

If taking other diabetes medications (especially insulin or sulfonylureas), your risk of low blood sugar increases. Your doctor may need to adjust your diabetes medication doses.

Other Oral Medications

Foundayo may affect how your body absorbs other oral medications. Take other oral medications at least 30 minutes before or 1 hour after your Foundayo injection, or as directed by your healthcare provider.

When to Call Your Doctor

Contact your healthcare provider immediately if you experience any of the following warning signs:

Severe abdominal pain that won't go away, with or without vomiting
Persistent severe nausea or vomiting that prevents you from eating or drinking
Signs of low blood sugar: shakiness, sweating, dizziness, fast heartbeat, difficulty concentrating
Swelling of face, lips, tongue, or throat; difficulty breathing
Yellowing of skin or eyes, or severe abdominal pain (signs of gallbladder problems)
Chest pain or shortness of breath
Severe allergic reactions or rash
Vision changes (for patients with diabetes)
Decreased urination or swelling in legs/feet (signs of kidney problems)
Any side effects that are severe, persistent, or concerning

Frequently Asked Questions

Do Foundayo side effects go away? +

Yes, many Foundayo side effects tend to improve over time as your body adjusts to the medication. Most patients experience the most pronounced side effects during the initial weeks at each new dose level. Common side effects like nausea often decrease significantly after the first few weeks. However, some side effects may persist or develop differently in different individuals. If side effects remain severe after several weeks, discuss alternative management strategies with your healthcare provider.

What is the most common side effect of Foundayo? +

Nausea is the most common side effect of Foundayo, especially during dose escalation. It typically improves as your body adjusts to each dose level. Starting with a low dose and gradually increasing it (slow titration) helps minimize nausea and other gastrointestinal side effects. Taking Foundayo with food, eating smaller meals, and staying hydrated can also help manage nausea. Most patients find that nausea becomes less bothersome after the first few weeks at each new dose.

Can Foundayo cause hair loss? +

Hair loss has been reported in some patients taking Foundayo, particularly during significant weight loss. This is thought to be related to rapid weight loss and nutritional changes rather than a direct effect of the medication itself. The hair loss is typically temporary and reverses as your body stabilizes at a new weight. Ensuring adequate protein and nutrient intake, including iron, zinc, and B vitamins, may help minimize this side effect. If you're concerned about hair loss, discuss it with your healthcare provider.

Is nausea from Foundayo worse than from Wegovy? +

Nausea is a common side effect of both Foundayo and Wegovy, as they are both GLP-1 receptor agonists that work similarly in the body. The severity and frequency of nausea can vary significantly between individuals and between the medications. Most patients find that nausea improves over time with continued use and proper dosing strategies. Individual response varies based on factors like genetics, metabolism, diet, and how quickly doses are escalated. Your healthcare provider can help determine which medication may be better tolerated for you personally.

Ready to Get Started?

If you have questions about Foundayo side effects or whether it's right for you, speak with your healthcare provider. To begin your Foundayo treatment, visit Lilly Direct.

Get Foundayo

Important Disclaimer: This is not a complete list of side effects and possible interactions. For complete information about Foundayo, including all side effects, contraindications, and drug interactions, please see the full Prescribing Information at uspl.lilly.com/foundayo/foundayo.html.

If you experience any side effects while taking Foundayo, report them to the FDA at www.fda.gov/medwatch or by calling 1-800-FDA-1088.

This information is for educational purposes only and should not be considered medical advice. Always consult with your healthcare provider before starting, stopping, or changing any medication.