Premier Functional Medicine
Explore the difference between GLP1 weight loss medications.
Premier Functional Medicine | Chandler, Arizona
Updated October 27, 2026
Weight loss involves more than willpower, exercise and calorie tracking. Hunger, fullness, blood sugar, and the way your body uses energy all influence your weight. Medications such as semaglutide and tirzepatide can help address some of these biological factors. A newer medication, retatrutide, is being studied for similar goals.
Although these medications share some features, they are not interchangeable. Understanding their differences can help you discuss your options with your Premier Functional Medicine provider.
These medications activate hormone receptors, which are receiving points on cells that help control certain body functions. The word agonist means a substance that activates a receptor.
Semaglutide activates one receptor type, tirzepatide activates two, and retatrutide activates three. More targets does not automatically mean a medication is the right choice for every patient.
Semaglutide targets GLP-1 receptors and is an established medication with FDA-approved products for weight management and type 2 diabetes. Tirzepatide targets both GLP-1 and GIP receptors, offering dual-action benefits with FDA-approved products for weight management and type 2 diabetes. Retatrutide targets GLP-1, GIP, and glucagon receptors, providing triple-action effects, but it remains investigational and is not FDA-approved.
Approved uses depend on the specific product. These medications are sometimes grouped under the “GLP-1” umbrella, but tirzepatide and retatrutide act on additional receptors.
Semaglutide mimics the effects of glucagon-like peptide-1, or GLP-1, a hormone released after eating. It helps reduce appetite, increases fullness, slows stomach emptying, and supports insulin release when blood sugar is elevated.
For some people, this means smaller portions feel more satisfying and frequent thoughts about food become less distracting.
Semaglutide is the active ingredient in Wegovy, which has a weight-management indication, and Ozempic, which is approved for type 2 diabetes. These products have different prescribing instructions.
Weight loss is not its only potential benefit. Wegovy is also approved to reduce the risk of major cardiovascular events in certain adults with established heart disease and obesity. Your health history can influence whether this matters for your treatment plan.
Tirzepatide activates receptors for both GLP-1 and glucose-dependent insulinotropic polypeptide, or GIP. These pathways work together to influence blood sugar and appetite.
Tirzepatide is the active ingredient in Zepbound, which is approved for weight management in eligible adults, and Mounjaro, which is approved for type 2 diabetes. Zepbound is also approved to treat moderate to severe obstructive sleep apnea in adults with obesity.
In the 72-week SURMOUNT-5 study, adults with obesity or qualifying as overweight who did not have diabetes lost an average of:
The trial compared weekly tirzepatide at the highest tolerated dose of 10 or 15 mg with weekly semaglutide at 1.7 or 2.4 mg. Participants also received lifestyle guidance.
These are study averages, not guaranteed results. The findings applied to the doses and populations studied; they do not compare every currently available formulation or dose. Side effects, other health needs, cost, and access also matter when choosing treatment.
Retatrutide activates GLP-1, GIP, and glucagon receptors. Glucagon helps regulate blood sugar and energy use. Researchers are studying whether adding this third pathway can produce further improvements in weight and metabolic health.
Clinical trials have reported substantial weight loss, drawing attention to retatrutide’s potential. Results from separate studies cannot establish that it is better or safer than semaglutide or tirzepatide.
Common side effects of semaglutide and tirzepatide include nausea, vomiting, diarrhea, constipation, and abdominal discomfort. These symptoms may occur when starting treatment or increasing the dose.
Less common but serious risks include pancreatitis, gallbladder problems, severe digestive symptoms, and kidney injury related to dehydration. Low blood sugar is more likely when these medications are used with insulin or certain other diabetes medicines.
Both carry boxed warnings about thyroid C-cell tumors seen in rodents; whether this occurs in humans is unknown. They are contraindicated for people with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2, known as MEN2.
Weight-loss medications should not be used during pregnancy. Discuss pregnancy plans, breastfeeding, digestive conditions, and upcoming anesthesia with your provider. Tirzepatide can reduce the effectiveness of oral hormonal birth control after starting treatment and after dose increases; additional contraceptive precautions are needed.
Retatrutide’s safety profile remains under study. Seek prompt care for severe, persistent abdominal pain, repeated vomiting, or signs of dehydration.
The best treatment depends on your medical history, treatment goals, response, side effects, and ability to continue care.
Medication works best within a broader plan that includes balanced nutrition, adequate protein, resistance training, sleep, and follow-up. These habits support health and help preserve muscle during weight loss. At Premier Functional Medicine the focus is on a holistic approach that transforms your body composition for long term benefits.
Long-term treatment may be appropriate because obesity is a chronic condition. Weight regain can occur after medication is stopped, so a maintenance plan matters from the beginning.
No. Tirzepatide is a dual GIP/GLP-1 receptor agonist. Retatrutide is a triple GIP/GLP-1/glucagon receptor agonist. GLP-2 is a separate hormone associated with intestinal function.
Combining them is not recommended. A prescriber should guide any change between medications.
No. A medication’s effect on your overall health, its tolerability, and your ability to maintain treatment are just as important as pounds lost.
At Premier Functional Medicine, a consultation gives you an opportunity to review your health history, discuss your goals, and explore whether an approved weight-management medication may fit your care plan.
Schedule a consultation: premierfunctionalmedicine.com
Call: 480-275-2743
Visit: 900 W. Chandler Blvd., Suite A7, Chandler, AZ 85225
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This article is for educational purposes and does not replace personalized medical advice. Results vary, and medication approvals may change.
