FDA-Approved GLP-1 Drugs for Weight Loss

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.

The FDA has approved semaglutide and tirzepatide as the only GLP-1 medications indicated for weight loss in adults with obesity or overweight conditions. Both medications work by mimicking glucagon-like peptide-1, a hormone that signals fullness to the brain and slows stomach emptying. PlexusDx delivers clinically-backed weight loss therapy through licensed 503A compounding pharmacies across all 50 states.

Semaglutide: The First FDA-Approved GLP-1 for Weight Loss

Semaglutide earned FDA approval for chronic weight management in 2021 under the brand name Wegovy. In clinical trials, patients taking semaglutide lost approximately 15% of their body weight over 68 weeks compared to 2.6% in the placebo group. The medication is administered as a weekly injection, with doses adjusted gradually over several months to minimize side effects and maximize effectiveness.

PlexusDx offers compounded semaglutide injections starting at $149 per month through licensed 503A pharmacies. Compounded semaglutide delivers the same active pharmaceutical ingredient as the brand version but without the manufacturer's markup. Your dose may need to go up as your treatment progresses. Your price won't. This flat-rate pricing structure removes uncertainty from weight loss therapy budgeting.

Semaglutide works best when combined with lifestyle modifications including structured meal planning and regular physical activity. Most patients begin noticing appetite reduction within the first two weeks of treatment. The medication continues to show benefits for up to 12 months of continuous use, with research indicating sustained weight loss as long as patients remain on therapy.

Tirzepatide: The Dual-Action GLP-1 and GIP Receptor Agonist

Tirzepatide received FDA approval for weight management in 2023 under the brand name Zepbound, representing a breakthrough in dual-hormone receptor activation. Unlike semaglutide, which targets only the GLP-1 receptor, tirzepatide activates both GLP-1 and GIP receptors simultaneously. This dual mechanism produced weight loss of up to 22% in clinical trials—among the highest outcomes recorded in obesity research.

PlexusDx provides compounded tirzepatide injections beginning at $249 per month, offering patients access to this advanced therapy without insurance barriers. Tirzepatide is also injected once weekly, with dose titration occurring over 16 weeks to reach maximum therapeutic levels. Because tirzepatide engages two separate pathways, some patients experience superior appetite suppression and metabolic benefits compared to single-receptor medications.

The GIP receptor activation in tirzepatide may enhance weight loss beyond what GLP-1 activation alone achieves. Patients typically tolerate tirzepatide similarly to semaglutide, though individual responses vary based on genetic factors influencing peptide receptor sensitivity. The Precision Peptide Genetic Test from PlexusDx can identify whether you carry genetic variants in GLP1R or GIPR that predict stronger response to dual-action therapy.

Compounded Versus Brand-Name GLP-1 Medications

Brand-name Wegovy and Zepbound carry significant costs—often $1,000 to $1,500 monthly—and require insurance approval or cash payment at retail prices. Compounded versions from licensed 503A pharmacies contain identical active ingredients manufactured under strict FDA oversight but bypass manufacturer distribution markups. PlexusDx partners exclusively with 503A compounders, never 503B facilities, ensuring pharmaceutical-grade quality and potency standards.

Compounded medications offer the same clinical efficacy as brand versions because they contain the same molecular structure and dosage strength. The choice between compounded and brand therapy depends on insurance coverage and personal preference rather than medical effectiveness. PlexusDx compounded semaglutide begins at $149 monthly and compounded tirzepatide at $249 monthly—a fraction of brand pricing without membership fees or insurance requirements.

Both compounded and brand GLP-1s are HSA and FSA eligible through PlexusDx, providing additional savings pathways for eligible patients. Compounding allows dose adjustments based on individual tolerance and response, which many patients find advantageous during their first three months of treatment. Switching from one medication to another or adjusting your protocol is straightforward within the PlexusDx platform.

Personalized GLP-1 Selection Based on Genetic Response Patterns

Not every patient responds equally to semaglutide or tirzepatide due to differences in how their genetic code regulates peptide receptors and metabolic pathways. The PlexusDx Precision Peptide Genetic Test analyzes 14 metabolic pathways and 150+ genetic insights to identify your individual peptide-response profile. Key variants like GLP1R rs6923761 and GIPR rs1800437 significantly influence whether you'll achieve optimal weight loss on single-action versus dual-action GLP-1 therapy.

Genetic testing costs $99 as an add-on after your first month of treatment, allowing you to confirm your initial medication choice or optimize your protocol based on your unique biology. Patients carrying certain FTO variants (rs9939609) or MC4R variants (rs17782313) may experience faster metabolic adaptation, which the test can predict. PlexusDx uses these genetic insights to guide dose escalation timing and help predict whether you might benefit from combination therapy, such as the GLP-Squared dual-compound injection.

Understanding your genetic predisposition removes guesswork from therapy selection and accelerates the path to your weight loss goals. The test is particularly valuable if you've previously tried weight loss medications without satisfactory results or if you have a family history of metabolic resistance. Results arrive within 7–10 business days and include actionable recommendations from PlexusDx clinical advisors.

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

Are compounded GLP-1 medications from PlexusDx as safe and effective as FDA-approved brand versions?

Yes. Compounded semaglutide and tirzepatide contain identical active pharmaceutical ingredients manufactured under FDA oversight by licensed 503A compounding pharmacies. Efficacy and safety profiles are equivalent to brand medications; the difference is cost. PlexusDx medications cost significantly less because they bypass manufacturer distribut...

How much weight can I expect to lose with semaglutide or tirzepatide?

Clinical trials showed semaglutide produced approximately 15% body weight loss over 68 weeks, while tirzepatide achieved up to 22% body weight loss. Individual results vary based on starting weight, adherence to lifestyle changes, genetic response patterns, and dose optimization. The Precision Peptide Genetic Test can help predict your likely re...

Why does PlexusDx use flat monthly pricing instead of flat per-compound pricing?

Flat-rate pricing removes financial barriers to dose optimization. Your dose may need to go up as your treatment progresses. Your price won't. Whether you take a starting dose or a maximum dose, PlexusDx charges the same monthly rate, allowing your physician to adjust therapy based purely on clinical need rather than cost concerns. Semaglutide i...

What are the most common side effects of GLP-1 medications?

Nausea, vomiting, and constipation occur most frequently, especially during the first 4–8 weeks of treatment or after dose increases. These effects typically decrease over time as your body adjusts. Drinking adequate water, eating smaller meals, and including fiber gradually reduces gastrointestinal symptoms. Serious adverse events are rare and ...

How does the Precision Peptide Genetic Test help me choose between semaglutide and tirzepatide?

The test identifies genetic variants in your GLP1R and GIPR receptors that predict strength of response to single-action versus dual-action therapy. Patients with certain GLP1R variants may achieve excellent results on semaglutide alone, while others with GIPR variants typically see superior outcomes with tirzepatide's dual mechanism. The $99 te...

Which GLP-1 Are Approved for Weight Loss?