What Are the Names of the GLP-1 Drugs and How Do They Work?

Last reviewed: May 15, 2026 Last updated: May 15, 2026

Written by: Jay Hastings , CEO of PlexusDx

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance. His work has included scaling healthcare startups, leading CLIA lab integrations, and helping expand consumer access to precision health tools.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Science Liaison with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

Glucagon-like peptide-1 (GLP-1) medications have transformed how people approach sustainable weight loss and metabolic health. Each drug in this class shares a common mechanism but differs in formulation, dosing frequency, and specific effects on your body's hunger and blood sugar systems. This guide explains the names of leading GLP-1 therapies and the biological pathways they activate.

What Is GLP-1 and Why Does It Matter for Weight Loss?

GLP-1 stands for glucagon-like peptide-1, a naturally occurring hormone your intestines release when you eat. This hormone signals your brain that you are full, slows how fast food leaves your stomach, and helps regulate blood sugar levels. When GLP-1 receptors in your brain receive these signals, appetite decreases and satiety increases—allowing you to eat less without feeling deprived.

People with obesity or metabolic disorders often have reduced natural GLP-1 activity or diminished sensitivity to this hormone. GLP-1 medications mimic the structure and function of your body's native GLP-1, amplifying these appetite-suppressing and metabolic signals. This artificial boost helps restore balance to hunger regulation centers in the hypothalamus, leading to meaningful, sustained weight reduction.

Research from the STEP trials (semaglutide) and SURMOUNT trials (tirzepatide) demonstrates that GLP-1 agonists produce 15–22% body weight loss in people with obesity, significantly outperforming older weight loss medications. The effectiveness stems from this multi-system approach: less hunger, slower gastric emptying, improved blood sugar control, and reduced cravings for high-calorie foods.

How GLP-1 Medications Work: The Mechanism of Action

GLP-1 drugs function by binding to and activating GLP-1 receptors located throughout your brain, pancreas, stomach, and intestines. When a GLP-1 medication attaches to these receptors, it triggers a cascade of biological events that reshape how your body processes food and energy. The primary effect occurs in the appetite centers of your hypothalamus, where signals telling you to stop eating become stronger and more persistent.

A secondary mechanism involves slowing gastric emptying—the speed at which food moves from your stomach into your small intestine. This delayed emptying creates prolonged feelings of fullness after meals, naturally reducing portion sizes and snacking frequency. Additionally, GLP-1 agonists enhance insulin secretion when blood sugar rises, helping your pancreas respond more effectively to meals and preventing energy crashes that trigger overeating.

The third pillar of GLP-1 action targets your reward system. Food cravings and the psychological drive to eat involve dopamine and other neurotransmitters in areas like the nucleus accumbens. GLP-1 receptor activation modulates these reward pathways, reducing the hedonic pleasure of high-calorie, ultra-processed foods. This dual action—biological satiety plus reduced craving intensity—addresses both physical and psychological drivers of weight gain.

Semaglutide: Long-Acting GLP-1 for Weekly Dosing

Semaglutide is a synthetic GLP-1 receptor agonist designed to last seven days per injection or oral dose, allowing once-weekly treatment schedules. Originally developed for type 2 diabetes management, semaglutide demonstrated such powerful weight loss effects in clinical trials that it became the first GLP-1 explicitly approved for chronic weight management in people without diabetes. The STEP program—a series of rigorous randomized controlled trials—showed participants lost an average of 15.3% of their body weight over 68 weeks when using semaglutide alongside lifestyle changes.

PlexusDx offers two semaglutide formulations: compounded semaglutide injection at $149 monthly and oral semaglutide starting at $209 monthly. The injectable form delivers medication via subcutaneous injection once per week, while the oral tablet is taken daily with water on an empty stomach. Both forms are produced by licensed 503A compounding pharmacies and are available across all 50 states without insurance requirements or membership fees. Patients typically begin at a lower dose and increase gradually every four weeks to minimize gastrointestinal side effects and maximize tolerability.

Tirzepatide: Dual GLP-1 and GIP Receptor Agonist

Tirzepatide represents the next evolution in peptide therapy because it activates not just GLP-1 receptors but also GIP (glucose-dependent insulinotropic polypeptide) receptors. By targeting two related hormone pathways simultaneously, tirzepatide produces more robust weight loss and metabolic improvements than single-target GLP-1 agents. The SURMOUNT clinical trials demonstrated that tirzepatide achieved up to 22.5% body weight reduction—the highest efficacy reported for any weight loss medication to date.

PlexusDx provides tirzepatide in two formats: compounded tirzepatide injection ($249 monthly) for weekly subcutaneous administration, and oral tirzepatide ($279 monthly) for daily dosing. Like semaglutide, tirzepatide from PlexusDx originates from licensed 503A compounding pharmacies and requires no insurance, membership, or out-of-pocket maximums. The injectable version maintains activity for seven days, while the oral form offers flexibility for patients who prefer pill-based therapy. Starting doses are conservative and titrated upward every 4 weeks based on tolerance and response.

Other GLP-1 Medications: Liraglutide, Dulaglutide, and Exenatide

Beyond semaglutide and tirzepatide, the GLP-1 drug class includes several other options with different pharmacokinetic profiles and dosing schedules. Liraglutide is a synthetic GLP-1 agonist requiring daily injections and was the first medication in this class approved for weight management. Dulaglutide, another synthetic GLP-1 agonist, offers once-weekly dosing via subcutaneous injection and carries similar efficacy to semaglutide but with a slightly different side-effect profile. Exenatide, an exendin-4–based GLP-1 agonist, comes in both twice-daily and once-weekly formulations and was among the earliest GLP-1 drugs approved for diabetes before weight loss applications became prominent.

Each of these agents binds to GLP-1 receptors and activates the same hunger-suppression and metabolic pathways, but they differ in half-life, injection frequency, manufacturing source, and individual tolerability. Some patients respond better to one GLP-1 drug than another due to genetic variation in GLP1R gene expression or differences in how their bodies metabolize each compound. PlexusDx's Precision Peptide Genetic Test analyzes the GLP1R rs6923761 variant and 48 other peptide-pathway markers to help identify which therapy aligns best with your unique biology, optimizing outcomes and minimizing trial-and-error prescribing.

Choosing the Right GLP-1 Medication for Your Goals

Selecting between semaglutide, tirzepatide, and other GLP-1 options requires consideration of several factors: desired weight loss magnitude, injection frequency preference, side-effect tolerance, budget, and individual genetic predispositions. Tirzepatide tends to produce slightly greater body weight reduction than semaglutide in head-to-head analyses, making it ideal for people seeking maximum results. Semaglutide offers a longer track record of safety data and may suit those preferring a well-established therapy or experiencing GIP-related sensitivity.

PlexusDx also offers innovative combination therapies like GLP-Squared (a dual compound priced $249 monthly) and the Microdose GLP-1 Protocol ($129 monthly) for patients seeking tailored approaches. The Precision Peptide Genetic Test ($99 add-on or $298 standalone) evaluates genetic variants in GIPR rs1800437, GLP1R rs6923761, FTO rs9939609, and MC4R rs17782313—revealing predispositions in peptide genetic pathways that predict individual medication response. All PlexusDx medications are HSA and FSA eligible, removing financial barriers to access. A clinical consultation with PlexusDx specialists can match you with the most effective therapy for your metabolism and lifestyle.

Frequently Asked Questions About What Are the Names of the GLP-1 Drugs and How Do They Work?

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Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

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