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.
A standard semaglutide pen holds enough medication for multiple weekly injections, typically lasting 4 weeks when you follow a dose-escalation protocol. Understanding your pen's capacity and how your dose advances over time helps you plan refills and track your weight loss progress effectively. PlexusDx delivers compounded semaglutide from licensed pharmacies, starting at $149 per month—flat pricing regardless of your dose level.
How Many Weekly Doses Come in One Semaglutide Pen
A single semaglutide pen contains enough medication to support a full month of weekly injections when you begin treatment at the standard starting dose of 0.25 milligrams. As your dose increases during the first four weeks, you'll inject once per week—meaning one pen typically lasts exactly 28 days. Each pen is prefilled and ready to use, with a dial mechanism that lets you select your prescribed dose for that week.
The number of actual injections from one pen never changes: you get four weekly doses per pen, period. What varies is the amount of medication in each injection as your body adapts to treatment. For example, week one you inject 0.25 mg, week two 0.5 mg, week three 0.75 mg, and week four 1.0 mg—all from the same pen. This design means you'll need one new pen every month during your dose-escalation phase.
Understanding Semaglutide Dose Titration and Supply Timing
Dose titration is a four-week process where your semaglutide dose gradually increases to help your body adjust and minimize side effects. Starting low allows your appetite-suppression pathway to activate gently, reducing nausea and gastrointestinal discomfort. By week four, most patients reach their target maintenance dose—typically between 1.0 and 2.4 milligrams per week, depending on your metabolic profile and treatment goals.
Once you reach your maintenance dose in week four, that same dose repeats every week going forward. This means one pen still lasts four weeks, and your monthly prescription remains consistent. PlexusDx simplifies this timeline by sending your monthly supply on schedule, so your refill arrives before you run out. No need to calculate doses or worry about pen inventory—your flat $149 monthly rate covers all four injections, regardless of which week's dose you're on.
Comparing Pen Supply to Oral and Dual-Compound Options
Semaglutide injection pens offer a fixed monthly supply that never changes, making planning straightforward. Oral semaglutide tablets work differently—they're taken once daily, so one month's supply looks like a bottle of 30 tablets rather than four pens. Both delivery methods work on the same titration schedule for dose adjustment, but injection therapy often produces stronger appetite suppression because the medication enters the bloodstream directly without stomach breakdown.
PlexusDx also offers GLP-Squared Injection, a dual-compound combining semaglutide and tirzepatide in one pen for patients who benefit from both GLP-1 and GIP receptor activation. This option starts at $249 per month and provides the same four-week supply as single-agent semaglutide, but with synergistic effects on weight loss and blood sugar control. Your Precision Peptide Genetic Test can reveal whether your GLP1R, GIPR, or MC4R variants suggest stronger response to combination therapy.
Planning Your Refills and Maximizing Your Monthly Supply
PlexusDx schedules your monthly refill to arrive before your current pen runs out, eliminating gaps in treatment. This continuity matters because stopping and restarting semaglutide can reset your appetite-suppression response and derail weight loss momentum. Set a calendar reminder for day 25 of each month to confirm your next shipment is en route—if it hasn't shipped, contact PlexusDx immediately to prevent a lapse.
To maximize your supply, inject on the same day each week (usually Friday or Sunday works best for weekly schedules). This habit prevents missed doses and helps you track exactly when you'll need your next pen. Store unopened pens in the refrigerator between 2–8°C, and once you begin using a pen, you can keep it at room temperature for up to 28 days. If you travel or your schedule shifts, contact your PlexusDx provider to adjust your delivery date—your flat monthly rate never changes, so there's no cost to customize timing.
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 many injections come in one semaglutide pen?
One pen contains exactly four weekly doses. You inject once per week for four weeks, then begin a new pen. During month one, your dose increases each week (0.25 mg → 0.5 mg → 0.75 mg → 1.0 mg), but all four doses come from the same pen.
What happens to my pen supply once I reach my target dose?
Once you complete the four-week titration and reach your maintenance dose in week four, that same dose repeats every week indefinitely. You still use one pen per month, but now all four injections contain your stable, therapeutic dose instead of increasing amounts.
Does PlexusDx charge me more if my dose goes higher?
No. PlexusDx pricing is flat—your semaglutide injection starts at $149 per month and stays $149 per month regardless of whether you're on week one's 0.25 mg dose or week four's 1.0 mg maintenance dose. Your dose may need to go up. Your price won't.
Are PlexusDx semaglutide pens the same as brand-name Ozempic?
PlexusDx semaglutide is compounded at licensed 503A pharmacies using the same active ingredient as brand Ozempic, but it is not FDA-approved as a finished product. The efficacy and side effect profile are equivalent when formulated by accredited facilities. Many patients find compounded semaglutide more affordable while achieving identical weight loss results.
Can the Precision Peptide Genetic Test predict how many doses I'll need?
Your Precision Peptide Genetic Test reveals how your GLP1R, GIPR, FTO, and MC4R variants influence appetite, metabolism, and medication response. These insights help PlexusDx providers predict whether you'll optimize at 1.0 mg, 1.7 mg, or 2.4 mg weekly—helping you reach your target dose faster and with fewer adjustments.
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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