GLP-1 Weight Loss Explained: Semaglutide and Tirzepatide Basics

What GLP-1 Medications Are

GLP-1, or glucagon-like peptide-1, receptor agonists are a class of medications that mimic a hormone your body naturally produces when you eat. The hormone does three relevant things: it tells your brain you are full, it slows the rate at which your stomach empties, and it helps regulate blood sugar.

These medications were originally developed for type 2 diabetes. In the clinical trials, researchers noticed participants were losing significant weight as a side effect. That led to FDA approval for chronic weight management in adults with obesity or weight-related health conditions.

Semaglutide vs Tirzepatide

At CMA we prescribe both.

• Semaglutide (brand names Wegovy and Ozempic, made by Novo Nordisk). Targets the GLP-1 receptor only. In the STEP-1 clinical trial, average weight loss was about 15 percent of body weight over 68 weeks.
• Tirzepatide (brand names Zepbound and Mounjaro, made by Eli Lilly). Targets both GLP-1 and a second receptor called GIP. In the SURMOUNT-1 trial, average weight loss was 15 to 21 percent depending on dose, over 72 weeks.

Tirzepatide has shown somewhat higher average weight loss in trials. Semaglutide has a longer safety record. Dr. Crenshaw recommends based on your medical history, insurance and access considerations, and what you are looking to address.

How the Program Works at CMA

The program is physician-supervised from start to finish. That means:

• An initial consultation covering medical history, baseline measurements, and candidacy assessment
• A personalized prescription with a dose titrated from low to therapeutic
• Regular check-ins for progress tracking, dose adjustment, and accountability
• Nutritional and lifestyle guidance built into the plan

What to Expect

Most patients experience some mild side effects early in treatment as their body adjusts. Nausea, constipation, mild abdominal discomfort, and fatigue are the most common. These usually diminish as treatment continues. Weight loss is gradual, not immediate. The medication works by changing your hunger signals, not by blocking calories.

Who It Is For

GLP-1 treatment is appropriate for adults with a BMI of 30 or higher, or a BMI of 27 or higher with at least one weight-related condition such as high blood pressure, type 2 diabetes, or high cholesterol. It is not right for every patient. Personal or family history of medullary thyroid carcinoma, MEN2, or pancreatitis are among the contraindications we screen for.

Why a Med Spa, Not a Weight Loss Clinic

Weight resistance is usually hormonal, not a willpower problem. Many patients come to CMA after years of trying and failing with diet and exercise alone. Combining medical weight management with access to aesthetic treatments, including skin tightening after significant weight loss, gives you a single provider who knows your whole picture.