Few topics in wellness have drawn as much attention as GLP-1 therapy, and few are surrounded by as much noise. At Calibrate IV, we believe the right starting point is the evidence: what these medications do in the body, who they were studied in, and what a physician-guided program should look like. This guide walks through all three.

What Is GLP-1 Therapy?

GLP-1 stands for glucagon-like peptide-1, a hormone your gut releases after eating. It signals fullness to the brain, slows how quickly the stomach empties, and helps the pancreas release insulin when blood sugar rises. GLP-1 medications, such as semaglutide, and dual GIP/GLP-1 medications, such as tirzepatide, are designed to amplify these natural signals. In practical terms, this can mean feeling satisfied sooner, staying satisfied longer, and experiencing fewer food-focused thoughts throughout the day, alongside support for healthier blood sugar regulation.

These are prescription medications. They are intended to be used together with a reduced-calorie eating pattern and regular physical activity, not as a replacement for them.

What the Research Shows

Weight reduction

• Semaglutide 2.4 mg (STEP 1; Wilding et al., New England Journal of Medicine, 2021; human randomized controlled trial, 1,961 adults): over 68 weeks, average body weight change was about 14.9% with semaglutide versus about 2.4% with placebo, with both groups receiving lifestyle support.
• Tirzepatide (SURMOUNT-1; Jastreboff et al., New England Journal of Medicine, 2022; human randomized controlled trial, 2,539 adults): over 72 weeks, average weight change ranged from roughly 15% to 21% across the three doses studied, compared with about 3% with placebo.

Individual results vary widely. These figures are group averages from clinical trials, and they do not predict what any one person will experience.

Visceral fat and body composition

Visceral fat is the fat stored deep in the abdomen around the organs, and it is closely tied to metabolic health. In a DXA body composition substudy of SURMOUNT-1 (Look et al., Diabetes, Obesity and Metabolism, 2025; human randomized controlled trial substudy, 160 participants with paired scans), tirzepatide was associated with greater reductions in visceral fat mass and waist circumference than placebo. Roughly three quarters of the weight lost was fat mass and about one quarter was lean mass, a split similar to the placebo group.

Context worth knowing: the visceral fat findings came from a post hoc analysis, visceral fat was estimated by DXA rather than measured directly, and the study was sponsored by the drug manufacturer. Lean mass loss is a real consideration, which is one reason protein intake and resistance training are part of a well-designed program.

Cardiovascular health

In the SELECT trial (Lincoff et al., New England Journal of Medicine, 2023; human randomized controlled trial, 17,604 adults), people with overweight or obesity and established cardiovascular disease, but without diabetes, had about a 20% lower rate of major cardiovascular events on semaglutide 2.4 mg than on placebo. This finding applies to that specific population and should not be generalized to everyone.

What happens if treatment stops?

This is where the word "lasting" needs care. In STEP 1 follow-up (Wilding et al., Diabetes, Obesity and Metabolism, 2022; human extension study), participants regained about two thirds of their prior weight loss within a year of stopping semaglutide. SURMOUNT-4 (Aronne et al., JAMA, 2024; human randomized withdrawal trial) found the same pattern with tirzepatide: those switched to placebo regained weight, while those who continued treatment kept losing. Current evidence suggests that GLP-1 therapy works best as part of a long-term plan built around nutrition, movement, and ongoing clinical oversight.

Who May Be a Candidate?

FDA-approved labeling for chronic weight management generally considers adults with a body mass index (BMI) of 30 or higher, or a BMI of 27 or higher with at least one weight-related health condition, such as high blood pressure, type 2 diabetes, or abnormal cholesterol. A GLP-1 program may be worth discussing with a provider if you:

• Have a BMI of 27 or higher along with a weight-related health condition, or a BMI of 30 or higher
• Are managing weight-related health concerns alongside your weight
• Have found that diet and exercise alone have not produced the results you hoped for in the past

BMI is a screening tool, not a verdict. Eligibility is always a clinical decision made after a full review of your history, labs, medications, and goals.

Safety: What to Discuss With Your Provider

Like any prescription therapy, GLP-1 medications carry risks. The most common side effects are gastrointestinal, including nausea, diarrhea, constipation, and vomiting, and they tend to be most noticeable when starting or increasing a dose. Less common but more serious risks include pancreatitis and gallbladder problems. Semaglutide and tirzepatide also carry a boxed warning about thyroid C-cell tumors seen in animal studies, and they are not recommended for people with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2. They are also not recommended during pregnancy.

This is why a proper medical evaluation comes first, and why ongoing monitoring matters.

The Calibrate IV Approach

A GLP-1 prescription is a starting point, not the whole program. At Calibrate IV, our physician-guided approach is built around a clinical evaluation, personalized planning, and follow-up with a licensed care team. With locations in Miami, New York, and Las Vegas, plus mobile services, we bring the visit to you and skip the waiting room.

Ready to find out whether a GLP-1 program may be right for you? Visit calibrateiv.com, call 1-844-416-2546, or email concierge@calibrateiv.com. Follow along at @calibrateivhydration for more evidence-based wellness education.

Frequently Asked Questions

Is GLP-1 therapy a replacement for healthy habits?

No. In the pivotal trials above, participants in both the treatment and placebo groups received lifestyle support. The medications are intended to work alongside nutrition and physical activity.

Will I need to stay on it indefinitely?

Trial data show weight regain after stopping, so duration is an important conversation to have with your provider. The right plan depends on your health, your goals, and how you respond.

Can I protect muscle while losing weight?

Adequate protein and resistance training are commonly recommended to help support lean mass during weight reduction. Your provider can tailor guidance to you.

This article is for educational purposes only and is not medical advice. GLP-1 medications are prescription therapies, and eligibility is determined by a licensed provider. Results vary. The information above supports, and does not replace, a consultation with your healthcare provider.