What Are All 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, or GLP-1, medications have transformed how millions approach sustainable weight loss and metabolic health. These injectable and oral treatments work by mimicking your body's natural hunger-regulating hormone, helping you feel fuller longer and reducing cravings. Understanding how different GLP-1 options function can help you make an informed decision about which therapy aligns with your health goals.

How GLP-1 Medications Work at the Cellular Level

Your body naturally produces glucagon-like peptide-1 in the small intestine in response to food intake. This hormone binds to receptors in your brain's appetite centers, slowing stomach emptying and signaling satiety to reduce how much you eat. GLP-1 drugs amplify this signal, creating a sustained feeling of fullness that persists between meals and helps prevent overeating.

Beyond appetite suppression, GLP-1 medications improve how your body handles glucose by stimulating insulin release when blood sugar rises. This dual action—reduced hunger plus better blood sugar regulation—explains why these medications support both weight loss and metabolic improvements. The effect is proportional to your individual biology; genetic variations in GLP-1 receptor sensitivity and other peptide pathways influence how effectively you respond.

Clinical research, including landmark STEP trials for semaglutide, demonstrated that participants lost an average of 10–15% of body weight over 68 weeks compared to placebo. These results reflect the medication's impact on your nervous system and metabolism working together, not simply eating less through willpower alone.

Semaglutide: Long-Acting GLP-1 for Sustained Appetite Control

Semaglutide is a synthetic GLP-1 analog designed to last longer in your body than the natural hormone. Available as a weekly injection or daily oral tablet, semaglutide reaches peak levels gradually over several days, maintaining steady appetite suppression throughout the week. This extended duration means you receive consistent hunger reduction without daily injections, making adherence simpler for many patients.

Semaglutide binds more tightly and persistently to GLP-1 receptors than older medications, amplifying its metabolic effects. STEP trials showed participants achieved weight reductions of 14–18% with the highest doses, with many maintaining losses long-term. PlexusDx offers both compounded semaglutide injection ($149/mo) and oral semaglutide ($249/mo+), allowing you to choose the delivery method that fits your lifestyle.

Your genetic variants in the GLP1R gene—particularly rs6923761—influence how strongly your receptors respond to semaglutide. The Precision Peptide Genetic Test ($99 add-on) reveals your predispositions in this pathway, helping predict whether semaglutide may be especially effective for your body's unique biology.

Tirzepatide: Dual-Action Peptide for Enhanced Weight Loss

Tirzepatide represents a newer class called GIP/GLP-1 receptor agonists, meaning it activates two hormone pathways simultaneously rather than one. By stimulating both GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) receptors, tirzepatide creates a more powerful signal for satiety and metabolic improvement. SURMOUNT trials showed participants lost 20–22% of body weight—significantly more than semaglutide-only therapy—making it an option for those seeking maximum results.

Because tirzepatide works through two pathways, your genetic profile becomes even more informative. Variants in GIPR (rs1800437) and GLP1R genes determine your receptor density and sensitivity to dual stimulation. PlexusDx provides compounded tirzepatide injection ($249/mo) and oral tirzepatide ($279/mo), with the Precision Peptide Genetic Test helping identify whether dual-pathway activation aligns with your peptide biology.

Liraglutide: Shorter-Acting GLP-1 Requiring Daily Dosing

Liraglutide was among the first GLP-1 medications approved for weight loss and remains widely used, though it requires daily injection to maintain steady appetite suppression. Because it clears from your bloodstream more rapidly than semaglutide, consistent daily dosing is essential to prevent hunger from returning between injections. Many patients transition from liraglutide to longer-acting options to simplify their treatment schedule.

Liraglutide's shorter half-life means dose adjustments and dose escalation take place more gradually over 4–5 weeks compared to weekly medications. This slower titration allows your body to acclimate but requires greater patience during the initial treatment phase. Research shows liraglutide produces approximately 5–10% weight loss in typical use, making it effective but generally less powerful than semaglutide or tirzepatide.

Dulaglutide, Exenatide, and Lixisenatide: Alternative GLP-1 Options

Dulaglutide is a once-weekly injection that bridges the gap between liraglutide's daily dosing and semaglutide's superior potency. It provides reasonable appetite suppression and metabolic benefits with weekly convenience, making it suitable for patients who want fewer injections than daily therapy but prefer a medication with an extensive safety track record. Weight loss typically ranges from 8–12% in clinical populations.

Exenatide and lixisenatide are earlier-generation GLP-1 medications that function similarly but require more frequent dosing (twice or three times daily for exenatide; once daily for lixisenatide). These agents remain options in certain settings but are less commonly chosen for weight loss compared to newer, longer-acting alternatives. Their shorter duration of action and less potent receptor binding result in smaller average weight reductions of 3–8%.

All five medication classes work through the same fundamental GLP-1 pathway but differ in duration, potency, and how well they bind to receptors. Your individual genetic background—including variants in FTO (rs9939609) and MC4R (rs17782313) that influence metabolic rate and appetite—plays a significant role in determining which medication produces the best results for your body.

Choosing Your GLP-1 Therapy With Precision Testing

The Precision Peptide Genetic Test maps 14 metabolic pathways, 49 peptides, and 150+ genetic insights to reveal your predispositions in peptide biology. This test is not a pharmacogenomic screening for drug metabolism but rather an assessment of your inherent peptide pathway function—showing whether your GLP-1 receptors, GIP receptors, appetite-related genes, and metabolic genes favor a particular medication approach. With this information, PlexusDx helps match you to semaglutide, tirzepatide, or our proprietary Microdose Protocol ($129/month) or GLP-Squared dual compound ($249/mo).

PlexusDx medications come exclusively from licensed 503A compounding pharmacies, never outsourcing facilities, ensuring pharmaceutical oversight and consistency. All therapies are available across all 50 states without insurance requirements or membership fees, and they qualify for HSA and FSA reimbursement. Starting your GLP-1 journey with precision insights helps you avoid trial-and-error and move directly toward the medication and dose your biology is most likely to respond to.

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

Medical and Editorial Standards

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.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance. References are included at the end of the article when scientific, medical, or health-related claims are discussed.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.