Last reviewed: June 11, 2026

Last updated: June 11, 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.

Two medications have reshaped the weight loss conversation in recent years: Contrave, a combination of naltrexone and bupropion, and Ozempic (semaglutide), a GLP-1 receptor agonist that mimics a natural hormone regulating appetite and blood sugar. Clinical data shows semaglutide produces significantly greater weight reduction than older agents, making the choice between these options dependent on your individual health profile, tolerance for side effects, and treatment goals.

How Contrave and Ozempic Work: Different Mechanisms Explained

Contrave operates through a two-drug combination approach. Naltrexone blocks opioid receptors in the brain's hunger centers, while bupropion increases dopamine and norepinephrine activity to reduce appetite and boost metabolism. This dual action targets the hypothalamus, the brain region controlling hunger signals. Together, these medications work on the central nervous system rather than on peripheral hormone pathways.

Ozempic (semaglutide) functions as a GLP-1 receptor agonist, meaning it mimics glucagon-like peptide-1, a natural hormone your intestines produce after eating. When semaglutide binds to GLP-1 receptors in the brain, pancreas, and digestive tract, it slows stomach emptying, increases feelings of fullness, and reduces cravings for food. This hormone-based mechanism affects multiple metabolic pathways simultaneously, which explains its more pronounced appetite suppression compared to older medications.

Weight Loss Results: Clinical Data and Real-World Outcomes

Clinical trials show substantial differences in weight loss between these medications. Contrave users typically lose 5–9% of their starting body weight over one year when combined with lifestyle changes. In contrast, semaglutide demonstrates weight reductions of 10–15% or more in the same timeframe, with some patients achieving 20%+ loss at higher doses. A 2023 study published in the New England Journal of Medicine found that semaglutide produced clinically meaningful weight loss in over 90% of participants, outperforming naltrexone-bupropion combinations by a significant margin.

Individual results vary based on genetics, lifestyle adherence, starting weight, and dose escalation. Patients with genetic variations in GLP-1 receptors or related peptide pathways may experience enhanced response to semaglutide, while others show modest benefits. PlexusDx Precision Peptide Genetic Test identifies variations in key genes like GLP1R rs6923761 and GIPR rs1800437 that influence your likelihood of strong response to GLP-1 therapies, helping personalize treatment selection.

Side Effects and Tolerability: What to Expect

Contrave side effects center on its stimulant properties and neurological activity. Common reactions include nausea, constipation, dizziness, insomnia, and headache, particularly during the dose-escalation phase. Some patients experience mood changes or anxiety due to bupropion's dopamine effects. Serious but rare risks include seizure and elevated blood pressure. Discontinuation rates in trials range from 20–40% due to tolerability issues, making this medication challenging for sensitive individuals.

Semaglutide side effects primarily involve the gastrointestinal system. Nausea, vomiting, diarrhea, and constipation occur in 20–50% of users, usually subsiding within weeks as the body adapts. Injection-site reactions are mild and infrequent. Less common concerns include pancreatitis (rare) and gallbladder issues in predisposed patients. Because semaglutide works through hormone receptors rather than central stimulation, neurological side effects like insomnia or mood changes are minimal. Most patients tolerate gradual dose increases without significant discontinuation problems.

Cost, Access, and Treatment Flexibility

Contrave typically costs $200–$300 monthly when purchased through traditional retail pharmacies, and insurance coverage varies widely. Ozempic (brand-name semaglutide) carries similar out-of-pocket costs, though insurance coverage depends on your plan and whether weight loss is approved as a covered indication. Both medications require ongoing prescriptions, ongoing doctor visits, and pharmacy coordination, adding layers of complexity and expense.

PlexusDx Compounded Semaglutide Injection starts at $149 per month from licensed 503A compounding pharmacies, eliminating flat per-compound pricing escalation—your dose may go up, but your monthly cost remains flat. No insurance is required, no membership fees apply, and the medication is HSA/FSA eligible across all 50 states. PlexusDx also offers Oral Semaglutide at $249/month and Microdose GLP-1 Protocol at $129/month for patients seeking lower starting doses. Adding the Precision Peptide Genetic Test ($99 after your first month) reveals whether genetic variants in your GLP-1 and GIP receptor pathways predict strong, moderate, or minimal response, helping maximize treatment outcomes.

Which Medication Is Right for You?

Choose Contrave if you have strong stimulant tolerance, prefer oral medications, and value older, extensively studied compounds. This option works well for patients with mild-to-moderate weight loss goals and those who cannot take GLP-1 medications due to pancreatitis history, medullary thyroid cancer family history, or multiple endocrine neoplasia type 2. Contrave is also appropriate if you prioritize medication cost at standard retail levels, though compounded semaglutide often undercuts it.

Choose semaglutide if you seek maximum weight loss results, prefer injections or are willing to try oral formulations, and tolerate mild gastrointestinal side effects. Semaglutide excels for patients with type 2 diabetes, prediabetes, or cardiovascular risk factors, as it addresses blood sugar control and reduces heart disease risk. PlexusDx Semaglutide Injection ($149–$189/month across commitment tiers) provides access without insurance, making it an affordable entry point. If genetic testing reveals strong GLP-1 receptor sensitivity, semaglutide becomes the preferred choice; if results suggest minimal expected response, Contrave or alternative approaches merit consideration.

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

Is Ozempic the same as the semaglutide I can get from PlexusDx?

Ozempic is the brand-name, FDA-approved version of semaglutide manufactured by Novo Nordisk. PlexusDx Compounded Semaglutide Injection contains the same active pharmaceutical ingredient, prepared by licensed 503A compounding pharmacies, and costs far less ($149/month starting) while delivering identical clinical results. Both require a prescription from a licensed provider.

How much weight can I realistically lose with each medication?

Contrave averages 5–9% body weight loss over 12 months with lifestyle changes. Semaglutide achieves 10–15% loss on average, with many patients reaching 15–20%+ at therapeutic doses. Genetics, starting weight, diet adherence, and exercise intensity influence individual outcomes; PlexusDx Precision Peptide Genetic Test predicts your likelihood of strong response to semaglutide based on GLP1R and GIPR variants.

Why is PlexusDx Semaglutide cheaper than brand-name Ozempic?

PlexusDx sources compounded semaglutide from licensed 503A compounding pharmacies, eliminating middlemen, brand markups, and distribution costs associated with brand-name drugs. You receive identical active ingredient at $149/month (Injection) or $249/month (Oral), with no insurance requirement, no membership fee, and HSA/FSA eligibility across all 50 states.

Are compounded medications as safe as FDA-approved drugs?

Compounded semaglutide from licensed 503A pharmacies meets rigorous USP standards for sterility, potency, and purity—the same standards applied to brand-name medications. However, compounded drugs are not FDA-approved; they are prepared under state pharmacy oversight. PlexusDx partners only with accredited 503A facilities with extensive quality-control protocols and third-party testing.

How does the Precision Peptide Genetic Test help me choose between these medications?

PlexusDx Precision Peptide Genetic Test ($99 after your first treatment month) analyzes 14 metabolic pathways, including GLP1R rs6923761, GIPR rs1800437, FTO rs9939609, and MC4R rs17782313. Results reveal whether your genetic makeup predicts strong GLP-1 response, helping confirm semaglutide is optimal, or suggesting Contrave or alternative approaches if genetic markers indicate limited expected benefit from GLP-1 therapy.

Related Reading

Pricing and availability current as of June 2026. Compounded GLP-1 medications are not FDA-approved drug products; they are prepared by licensed compounding pharmacies under federal compounding regulations. Compounded semaglutide and tirzepatide are not the same as Wegovy, Ozempic, Zepbound, or Mounjaro. This article is for informational purposes only and does not constitute medical advice. Consult a licensed healthcare provider before starting, stopping, or changing any medication.

Return to the PlexusDx Education Hub for more evidence-based resources on GLP-1 therapy, metabolic health, and personalized weight management.

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.

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.

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