What Is a Dual GIP/GLP-1 Agonist?
A dual GIP/GLP-1 agonist is a prescription medicine that activates the receptors for two gut hormones: glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). Tirzepatide is the first medicine in this class. It is sold as Mounjaro for type 2 diabetes and as Zepbound for weight management and obstructive sleep apnea.
GIP and GLP-1 are incretins, hormones the gut releases after you eat. They signal the pancreas to release insulin and act on the brain's fullness (satiety) center. A standard GLP-1 receptor agonist, such as semaglutide, activates only the GLP-1 receptor.
Dual GIP/GLP-1 Agonist at a Glance
| Also called | Dual GIP and GLP-1 receptor agonist (part of the incretin mimetic class) |
|---|---|
| Example | Tirzepatide (Mounjaro, Zepbound) |
| What it treats | Type 2 diabetes, weight management and obesity-related sleep apnea |
| How it works | Reduces appetite and food intake, helps release insulin and slows stomach emptying |
| How it's given | Injection under the skin once a week |
| How long it lasts | Taken once a week for as long as it helps. Some weight usually returns after stopping. |
| Common side effects | Nausea, diarrhea, vomiting and constipation |
| FDA status | Approved (Mounjaro 2022, Zepbound 2023). Boxed warning for thyroid tumors seen in rats. |
What Are Dual GIP/GLP-1 Agonists Used For?
Dual GIP/GLP-1 agonists are FDA-approved for type 2 diabetes, weight management and obesity-related sleep apnea:
- Mounjaro improves blood sugar in adults and children 10 and older with type 2 diabetes. It also lowers the risk of cardiovascular death, heart attack and stroke in high-risk adults with type 2 diabetes.
- Zepbound treats adults with a body mass index (BMI) of 30 or higher, or 27 or higher with a weight-related condition such as high blood pressure or type 2 diabetes.
- Zepbound also treats moderate to severe obstructive sleep apnea in adults with obesity. It was the first drug approved for this use.
Zepbound is used with a reduced-calorie diet and more physical activity. American Diabetes Association guidelines say nutrition, activity and behavioral therapy should accompany any obesity medicine.
How Do Dual GIP/GLP-1 Agonists Work?
A dual GIP/GLP-1 agonist works by mimicking two incretin hormones at once. It acts on brain areas that regulate appetite and food intake, helps the pancreas release the right amount of insulin when blood sugar is high, and slows stomach emptying.
How Is a Dual GIP/GLP-1 Agonist Taken?
A dual GIP/GLP-1 agonist such as tirzepatide is injected under the skin of the abdomen or thigh once a week, at any time of day, with or without meals. Another person can give the injection in the back of the upper arm. Treatment starts at 2.5 mg weekly. The dose rises in 2.5 mg steps at least 4 weeks apart, to reduce stomach side effects, up to a maximum of 15 mg in adults.
How Much Weight Loss Do Dual GIP/GLP-1 Agonists Cause?
Tirzepatide, a dual GIP/GLP-1 agonist, led to average weight loss of 15.0% to 20.9% over 72 weeks, depending on dose, in SURMOUNT-1, a trial of 2,539 adults with obesity or overweight but without diabetes. People on placebo lost 3.1%. According to NIDDK, most weight loss with weight management medicines happens within the first 6 months of starting.
Side Effects of Dual GIP/GLP-1 Agonists
The most common side effects of dual GIP/GLP-1 agonists affect digestion. They include nausea, diarrhea, vomiting, constipation, stomach pain, indigestion, burping and acid reflux, plus injection site reactions, fatigue and hair loss. In SURMOUNT-1, most digestive side effects were mild to moderate and happened while the dose was increasing.
Call your provider right away about:
- Stomach pain that won't go away, sometimes spreading to the back (possible pancreatitis)
- Gallbladder problems, such as gallstones
- Ongoing vomiting or diarrhea, which can lead to dehydration and kidney injury
- Face or throat swelling, or trouble breathing
- Low blood sugar, especially if you also take insulin or a sulfonylurea
Tell your providers you take tirzepatide before any planned surgery or procedure. Tirzepatide slows stomach emptying, and rare cases of food entering the lungs during general anesthesia or deep sedation have been reported with GLP-1 medicines.
Who Shouldn't Take a Dual GIP/GLP-1 Agonist?
People with a personal or family history of medullary thyroid cancer, or with multiple endocrine neoplasia syndrome type 2 (MEN 2), should not take a dual GIP/GLP-1 agonist. Tirzepatide caused thyroid tumors in rats, and whether it does in people is unknown. Other cautions include:
- A past serious allergic reaction to tirzepatide
- Severe gastroparesis
- Pregnancy, because tirzepatide may harm a fetus; Zepbound should be stopped once pregnancy is known
- Use with another tirzepatide product or a GLP-1 receptor agonist
- Birth control pills, which may work less well; switch to a non-pill method, or add a barrier method for 4 weeks after starting and after each dose increase
Dual GIP/GLP-1 Agonist vs. GLP-1 Receptor Agonist
A dual GIP/GLP-1 agonist activates two hormone receptors, while a GLP-1 receptor agonist activates one. Both treat type 2 diabetes and obesity.
| Dual GIP/GLP-1 agonist | GLP-1 receptor agonist | |
|---|---|---|
| Receptors | GIP and GLP-1 | GLP-1 only |
| Examples | Tirzepatide (Mounjaro, Zepbound) | Semaglutide (Ozempic, Wegovy), liraglutide (Saxenda, Victoza) |
| Forms | Weekly injection | Weekly or daily injection; semaglutide also as a pill |
| Weight loss beyond placebo (ADA summary) | 16.2% | Semaglutide 11.9%; liraglutide 4.5% |
| Not for people with a personal or family history of MTC or MEN 2 | Yes | Yes |
Dual GIP/GLP-1 Agonist Evaluation at GENEVA
At GENEVA Primary Care & Med Spa in Alpharetta, GA, a provider evaluates whether a dual GIP/GLP-1 agonist may suit you after reviewing your health history. Based on that evaluation, your provider recommends treatment at GENEVA or a referral to a specialist. Start through GENEVA's medical weight loss program or, for type 2 diabetes, chronic disease management. GENEVA serves patients from Alpharetta, Johns Creek, Milton, Roswell and Cumming.
Related Terms
- GLP-1 receptor agonist
- Tirzepatide injections
- Mounjaro
- Zepbound
- Tirzepatide titration schedule
- Compounded tirzepatide
- Insulin resistance
- Body mass index (BMI)
Dual GIP/GLP-1 Agonist FAQs
Is tirzepatide a dual GIP/GLP-1 agonist?
Yes. Tirzepatide is a dual GIP/GLP-1 receptor agonist and the first medicine of its kind. Mounjaro, approved in 2022, treats type 2 diabetes in adults and children 10 and older. Zepbound, approved in November 2023, treats obesity or overweight with a weight-related condition in adults, and since December 2024 it also treats moderate to severe obstructive sleep apnea in adults with obesity. Both are once-weekly injections. Zepbound shouldn't be combined with a GLP-1 receptor agonist.
What is the difference between a GLP-1 agonist and a dual GIP/GLP-1 agonist?
A GLP-1 agonist activates one gut-hormone receptor, GLP-1, while a dual GIP/GLP-1 agonist activates two, GIP and GLP-1. Both reduce appetite and help the pancreas release insulin. In an American Diabetes Association summary of meta-analyses, average weight loss beyond placebo was 16.2% for tirzepatide, 11.9% for semaglutide and 4.5% for liraglutide. Tirzepatide and semaglutide have similar digestive side effects, and both carry a thyroid boxed warning. The best choice depends on your health, goals and tolerance.
How much weight can you lose on a dual GIP/GLP-1 agonist?
In the SURMOUNT-1 trial, adults with obesity or overweight but without diabetes lost an average of 15.0% to 20.9% of their body weight over 72 weeks on tirzepatide, compared with 3.1% on placebo. At the 10 mg and 15 mg doses, 50% and 57% of participants lost 20% or more. If you haven't lost 5% of your starting weight after 12 weeks on the full dose, NIDDK says your provider will probably advise stopping.
Is tirzepatide better than semaglutide for weight loss?
In a head-to-head trial, tirzepatide led to more weight loss than semaglutide in adults with obesity who did not have diabetes. In SURMOUNT-5, a 72-week open-label trial of 751 adults funded by tirzepatide's maker, average weight loss was 20.2% with tirzepatide and 13.7% with semaglutide. Digestive side effects were the most common in both groups and were mostly mild to moderate. The right choice also depends on tolerance, other health conditions and coverage, so decide with your provider.
Are dual GIP/GLP-1 agonists safe?
Dual GIP/GLP-1 agonists are FDA-approved, but they have known risks. The most common side effects are nausea, diarrhea, vomiting and constipation, mostly mild to moderate and mainly while the dose is increasing. Less common but serious risks include pancreatitis, gallbladder disease, kidney injury from dehydration and serious allergic reactions. A boxed warning covers thyroid tumors seen in rats, so people with a personal or family history of medullary thyroid cancer, or with MEN 2, shouldn't use them.
What happens when you stop taking tirzepatide?
Some weight usually comes back after stopping tirzepatide. In the SURMOUNT-4 trial, adults first lost an average of 20.9% of their weight over 36 weeks. Those switched to placebo then gained back 14.0% over 52 weeks, while those who stayed on tirzepatide lost another 5.5%. NIDDK says healthy eating and regular physical activity may help you regain less. Don't stop tirzepatide on your own; talk with your provider first about side effects or other concerns.
Can a primary care provider prescribe a dual GIP/GLP-1 agonist?
Yes. A primary care provider can evaluate whether a dual GIP/GLP-1 agonist fits your needs. NIDDK lists the factors to weigh: likely benefits, possible side effects, current health issues and medicines, family medical history and cost. At GENEVA in Alpharetta, a provider reviews these, then recommends treatment at GENEVA or a referral to a specialist. The American Diabetes Association recommends checking weight and other body measurements at least every 3 months during active weight management.