How do semaglutide and tirzepatide work?
Semaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist. GLP-1 is a hormone, released by the body in response to eating, focused on the digestive system and brain. It slows how fast your stomach empties, reduces your appetite, and boosts insulin secretion while reducing the secretion of glucagon. This helps lower your blood glucose levels. For weight loss, the primary benefit of semaglutide is its appetite-suppressing effect, which leads to taking in fewer calories.
Tirzepatide, on the other hand, is a dual glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 receptor agonist. This means that tirzepatide produces the same effects of GLP-1, and uses GIP, another hormone, to boost your body’s insulin secretion. This can potentially affect how your body metabolizes fat—and help regulate your appetite. These combined effects can have positive impacts on both your blood glucose control and weight loss.
What’s the difference in how these drugs work?
The key difference between these two medications lies in tirzepatide’s dual action. While semaglutide exclusively targets GLP-1 receptors, tirzepatide’s additional effect on GIP receptors might help you lose more weight. This is because while semaglutide focuses on one pathway to help you eat less and control blood sugar, tirzepatide uses two pathways for potentially greater effects on weight and blood sugar control.
What are the side effects of these drugs?
Semaglutide and tirzepatide share the same side effects. The most common ones are gastrointestinal issues like nausea, vomiting, diarrhea, and constipation. These side effects, which can stop over time as your body adjusts to the medication, happen because the drugs slow the speed at which your stomach empties.
What should I know about the clinical trial results?
The SURMOUNT-3 trial was a significant study that evaluated the efficacy of tirzepatide in patients with obesity. It also aimed to assess the drug’s impact on various health markers, including blood pressure, cholesterol levels, and glycemic control.
The trial included participants who had an average body mass index (BMI) of approximately 38. They ranged in age from 18 to 75 years, with an average age of 50. This diverse demographic of people provided a broad perspective on the drug’s efficacy across a wide age group.
The results of the SURMOUNT-3 trial were striking. Participants who received tirzepatide experienced an average weight loss of approximately 21% of their baseline body weight over a period of 72 weeks, which translated to an average weight loss of around 46 pounds.
The trial also demonstrated significant improvements in various metabolic health markers. Participants’ blood pressure and cholesterol levels decreased, which meant they had an overall enhancement in their cardiovascular health. These weight loss and health benefits over the 72-week study period showed tirzepatide’s potential for helping those with obesity lose weight.
The primary goal of the Select Trialwas to assess the weight loss efficacy of semaglutide and its impact on cardiovascular health. The study aimed to determine whether the med could provide dual benefits of weight reduction and cardiovascular risk reduction.
Participants had an average BMI of about 35, and the age range was from 30 to 85 years old, with an average age of around 60. They had existing cardiovascular conditions.
The SELECT trial yielded impressive results. Participants treated with semaglutide achieved an average weight reduction of about 15% of their baseline body weight over 68 weeks. This translated to an average weight loss of approximately 35 pounds.
Beyond weight loss, the SELECT Trial highlighted semaglutide’s ability to reduce the risk of major cardiovascular events: People in the study experienced significant improvements in heart health markers.
What did these trials teach us about how these drugs compare?
Both medications demonstrated substantial weight loss benefits, but tirzepatide’s dual-action effect demonstrated a slight edge in terms of the amount of weight loss patients may experience. However, both drugs offer significant improvements in metabolic benefits—including reduced waist circumference, improved cardiovascular disease risk factors, and better control of blood sugar.
How to take these medications
Semaglutide
- Dosing: Semaglutide is typically started at a low dose (0.25 mg weekly) to minimize gastrointestinal side effects, then gradually increased to the maintenance dose of 2.5 mg weekly if needed.
- Administration: You get a shot once a week, with or without meals.
Tirzepatide
- Dosing:Tirezepatide dosing starts at 2.5 mg once a week, with incremental increases to 10 mg based on tolerance.
- Administration: Like semaglutide, tirzepatide is administered via a shot once a week, with or without meals.
Deciding which is right for you: semaglutide or tirzepatide
Both semaglutide and tirzepatide represent significant advancements in weight management, and can potentially help many patients. They both work well for weight loss and better metabolic health. Both medications have shown impressive results in their respective clinical trials. But without direct head-to-head comparisons, it is still hard to say whether one is superior to the other.
How should you choose between the two? It’s a very individual decision. Talk to your doctor about your ability to tolerate these drugs, as well as potential side effects, your health history, and your specific health goals.
I also encourage you to chat with a DietsMd Wellness Avisor to explore the options available in detail, so you can be informed when you speak to your doctor.
How ReflexMD works
- Get prescribed online: First, answer a few questions to see if you’re eligible. Then chat with one of our doctors (virtually), so he or she can develop your custom treatment plan.
- Your meds are delivered to your door: All medications are quality-checked and shipped in discreet packaging.
- Ongoing expert support: Your expert care team always has your back. Book unlimited virtual appointments and talk to your doctor anytime with 24/7 messaging.