What Are GLP-1 Medications? A Complete Guide

GLP-1 receptor agonists are a class of medications originally developed for type 2 diabetes that have shown remarkable effectiveness for weight management. These medications mimic a natural hormone called glucagon-like peptide-1 (GLP-1) that your body produces after eating.

How GLP-1 Medications Work

GLP-1 receptor agonists work through several mechanisms that together support significant weight loss:

Appetite Regulation: GLP-1 medications act on receptors in the brain that control hunger and satiety. They slow gastric emptying, helping you feel full longer after meals, and reduce the neural signals that drive food-seeking behavior.

Blood Sugar Control: By stimulating insulin release only when blood sugar is elevated, GLP-1 medications help maintain stable blood glucose levels. This reduces the energy crashes and cravings that often accompany blood sugar fluctuations.

Metabolic Effects: Research suggests GLP-1 receptor agonists may also [improve cardiovascular markers](/resources/glp1-medications-cardiovascular-health) including blood pressure, cholesterol levels, and inflammatory markers.

Types of GLP-1 Medications

The two most widely used GLP-1 medications for weight management are:

Semaglutide

Originally marketed as Ozempic (for diabetes) and Wegovy (for weight management), semaglutide is administered as a once-weekly injection. [Compounded semaglutide](/resources/compounded-semaglutide-what-it-is) offers an accessible alternative at a lower cost point — [compare costs here](/resources/compounded-semaglutide-cost-2026).

Tirzepatide

A dual GIP/GLP-1 receptor agonist that targets two hormonal pathways simultaneously. Originally marketed as Mounjaro (for diabetes) and Zepbound (for weight management), [compounded tirzepatide](/resources/compounded-tirzepatide-guide) has shown even greater weight loss in clinical trials.

What to Expect

Treatment typically follows a gradual dosage escalation schedule:

• Weeks 1-4: Starting dose to allow your body to adjust
• Weeks 5-8: First dose increase
• Weeks 9-12: Continued escalation toward maintenance dose
• Month 4+: Maintenance dose for ongoing results

Most patients begin noticing reduced appetite within the first 1-2 weeks. Measurable weight loss typically begins within the first month, with the most significant results occurring over 3-6 months.

Common Side Effects

The most common side effects are gastrointestinal and typically mild:

• Nausea (most common, usually improves over time)
• Decreased appetite
• Mild stomach discomfort
• Occasional constipation or diarrhea

Starting at a low dose and gradually increasing helps minimize these effects. Your prescribing clinician will monitor your progress and adjust dosing as needed.

See our detailed [semaglutide vs. tirzepatide comparison](/resources/semaglutide-vs-tirzepatide-weight-loss) if you are deciding between these medications.

Who Is a Good Candidate?

GLP-1 medications may be appropriate if you:

• Have a BMI of 30 or higher (obesity)
• Have a BMI of 27+ with at least one weight-related health condition
• Have not achieved adequate results with diet and exercise alone
• Do not have a personal or family history of medullary thyroid carcinoma or MEN 2 syndrome

Frequently Asked Questions

How much weight can I expect to lose?

Clinical trials show average weight loss of 15-20% of body weight over 68 weeks with semaglutide, and up to 22.5% with tirzepatide. Individual results vary based on starting weight, adherence, and lifestyle factors.

Are compounded GLP-1 medications safe?

Compounded medications dispensed through Prescriva are prepared by state-licensed 503A pharmacies under strict regulatory oversight. They are not FDA-approved, and compounded medications are not the same as, equivalent to, or substitutes for FDA-approved medications.

How long do I need to take GLP-1 medications?

Current evidence suggests that weight loss medications work best as a long-term treatment. Discontinuation often leads to weight regain. Your licensed clinician will work with you to determine the best long-term plan.

Can I take GLP-1 medications with other medications?

GLP-1 medications can interact with certain drugs, particularly insulin and sulfonylureas. Always disclose all current medications during your health assessment.

What happens during the health assessment?

The assessment is a comprehensive online questionnaire about your health history, current medications, and weight loss goals. A licensed clinician reviews your responses and determines if GLP-1 therapy is appropriate for you.

Sources

1. Once-Weekly Semaglutide in Adults with Overweight or Obesity. *New England Journal of Medicine.* 2021 doi:10.1056/NEJMoa2032183
2. Efficacy and Safety of GLP-1 Receptor Agonists for Weight Management. *The Lancet.* 2022 doi:10.1016/S0140-6736(21)01324-0
3. Semaglutide and Cardiovascular Outcomes in Patients with Overweight or Obesity. *New England Journal of Medicine.* 2023 doi:10.1056/NEJMoa2307563