What Are GLP-1 Products and How Do They Work

Last reviewed: June 4, 2026

Last updated: June 4, 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.

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.

This article is part of the PlexusDx Education Hub — science-backed guidance on GLP-1 medications, metabolic health, and precision weight management.

GLP-1 stands for glucagon-like peptide-1, a hormone your intestines release when you consume food. Medications that activate GLP-1 receptors signal your brain to feel fuller longer, eat less, and crave food less intensely—an approach backed by clinical trials showing average weight loss of 15–22% in one year.

How GLP-1 Receptor Agonists Reduce Hunger and Appetite

When you take a GLP-1 medication, it binds to special receptors in your brain's appetite control center, the hypothalamus. This activation tells your body you are satisfied with smaller portions, reducing the constant urge to eat between meals. The effect is not willpower-based—it is a biochemical shift that makes you genuinely less interested in food.

GLP-1 also delays how fast your stomach empties food into your small intestine. This slower digestion keeps you feeling full for hours after eating, which naturally leads to consuming fewer calories without hunger pangs or deprivation. Studies show patients on GLP-1 therapy report decreased cravings for high-sugar and high-fat foods within 2–4 weeks of starting treatment.

The Difference Between Semaglutide and Tirzepatide

Semaglutide activates only GLP-1 receptors, making it a single-action medication that has been studied extensively since its FDA approval for type 2 diabetes in 2017. Tirzepatide is a dual-action compound that activates both GLP-1 and GIP (glucose-dependent insulinotropic polypeptide) receptors, offering a broader effect on appetite and metabolism. Clinical trials show tirzepatide produces slightly larger average weight loss—up to 22% of body weight—compared to semaglutide alone.

Both medications are available through PlexusDx as compounded injections and oral formulations. Compounded Semaglutide Injection starts at $149 per month, while Compounded Tirzepatide Injection begins at $249 per month. Your dose may need to go up as your body adjusts, but your price won't—PlexusDx pricing remains flat across all dose levels.

Why Compounded GLP-1 Medications Offer Flexibility and Affordability

PlexusDx partners exclusively with licensed 503A compounding pharmacies to prepare GLP-1 medications tailored to your specific needs. Compounding allows for customized dosing schedules and formulations that may not be available commercially, and it eliminates the need for insurance approval or membership fees. This approach makes precision weight loss therapy accessible to all 50 states at transparent, affordable prices.

Compounded medications are created fresh by pharmacists who follow strict quality standards set by the U.S. Pharmacopeia and FDA oversight of compounding facilities. Unlike mass-produced pharmaceuticals, compounded GLP-1 gives you medication prepared specifically for your treatment plan, and you can use HSA or FSA funds to cover costs. Starting at $149 per month for Semaglutide Injection, PlexusDx makes personalized GLP-1 therapy more affordable than many commercial alternatives.

Personalized GLP-1 Selection Through Genetic Insights

Not every patient responds identically to the same GLP-1 medication. Genetic variations in your GLP-1 receptor gene, GIP receptor gene, and appetite-regulation pathways influence how effectively semaglutide or tirzepatide works for you. PlexusDx offers the Precision Peptide Genetic Test to identify your unique peptide-pathway genetics and predict which medication and dose strategy will work best.

The Precision Peptide Genetic Test analyzes key variants including GLP1R rs6923761, GIPR rs1800437, FTO rs9939609, and MC4R rs17782313—mapping 14 pathways and 49 peptides to generate 150+ personalized insights. This $99 add-on after your first month of treatment helps PlexusDx clinicians adjust your protocol with confidence, ensuring you get the right medication at the right dose for your genetic profile. Patients with genetic predispositions toward GLP-1 receptor sensitivity often see results faster and with better tolerability.

How Your Genetics Influence GLP-1 Response

Not everyone responds to GLP-1 medications the same way. Genetic variants — including GIPR rs1800437, GLP1R rs6923761, FTO rs9939609, and MC4R rs17782313 — influence how your body processes these medications, how much weight you lose, and how you tolerate side effects. PlexusDx maps 14 pathways, 49 peptides, and 150+ genetic insights to match each patient to the right medication, dose, and lifestyle protocol for their biology. The PlexusDx Precision Peptide Genetic Test ($99 add-on after your first month of treatment) gives your provider precise insight into your peptide genetic predispositions before the first prescription is written.

Access Personalized GLP-1 Care Through PlexusDx

PlexusDx offers six prescription GLP-1 protocols to all 50 states — no membership, no insurance required, async intake or live consult. The Semaglutide Injection starts at $149/mo. Medications are dispensed from licensed 503A compounding pharmacies following strict quality and safety standards. Add a Precision Peptide Genetic Test for $99 to personalize your protocol from day one.

Frequently Asked Questions

How quickly will I feel the appetite-suppressing effects of GLP-1 medication?

Most patients notice reduced hunger and food cravings within 5–14 days of starting treatment, though the effect strengthens over 2–4 weeks as your dose stabilizes. PlexusDx clinicians start you at a low dose to minimize side effects, then gradually increase to your therapeutic level based on how your body responds.

What clinical evidence supports GLP-1 therapy for weight loss?

The STEP trials, published in the New England Journal of Medicine, showed participants taking semaglutide lost an average of 15% of body weight over 68 weeks. The SURMOUNT trials for tirzepatide demonstrated even larger reductions, with participants losing up to 22% of body weight. These results represent the most robust weight-loss medication d...

How much does compounded semaglutide cost at PlexusDx?

Compounded Semaglutide Injection starts at $149 per month, with pricing remaining flat regardless of your dose level. PlexusDx accepts all 50 states, requires no insurance, and allows HSA/FSA payments for maximum affordability and flexibility.

Are there side effects I should know about before starting GLP-1?

Common mild side effects include nausea, constipation, and reduced appetite for certain foods—effects that typically decrease within 1–2 weeks. Serious side effects are rare but may include pancreatitis or gallbladder issues; PlexusDx clinicians monitor your health throughout treatment to ensure safety and adjust your plan if needed.

Will the Precision Peptide Genetic Test help me choose semaglutide or tirzepatide?

Yes. The test identifies genetic variations in your GLP-1 and GIP receptors, FTO gene, and appetite-regulation pathways that predict medication response. Patients with certain GLP1R variants may achieve better results with semaglutide or tirzepatide, helping PlexusDx clinicians recommend your ideal treatment from the start.

What Are GLP-1 Products and How Do They Work?