Last reviewed: June 9, 2026
Last updated: June 9, 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 receptor agonists like semaglutide work by slowing stomach emptying and reducing appetite, but they affect multiple body systems. Before beginning treatment and throughout your weight loss journey, certain lab tests help your healthcare provider monitor your safety and adjust your dose effectively.
Baseline Lab Tests Before Starting GLP-1 Therapy
Before your first injection or oral dose of semaglutide or tirzepatide, a baseline metabolic panel establishes your starting point. This panel typically includes fasting glucose, hemoglobin A1C (for diabetes risk), electrolytes, and kidney function markers like creatinine and eGFR. Your healthcare provider also checks liver enzymes (AST, ALT) and lipid levels to rule out pre-existing conditions that might affect GLP-1 safety.
A complete blood count (CBC) and thyroid-stimulating hormone (TSH) test round out baseline screening. Although GLP-1 medications are generally well-tolerated, these initial results create a comparison point for future monitoring. PlexusDx-partnered providers use these baseline values to personalize your starting dose and treatment timeline.
Kidney Function Monitoring on GLP-1 Medications
GLP-1 receptor agonists can affect hydration status and blood pressure, both of which influence kidney function over time. Your creatinine level and estimated glomerular filtration rate (eGFR) are checked at baseline and then monitored at 3-month and 6-month intervals, depending on your individual risk profile. Patients with pre-existing kidney disease or those taking certain blood pressure medications require more frequent kidney monitoring.
Dehydration is a common side effect of GLP-1 therapy because nausea and reduced appetite can lower fluid intake. Regular kidney labs help catch early signs of dehydration-related creatinine elevation. If your eGFR drops significantly or your creatinine rises, your PlexusDx-connected provider may recommend increased water intake, slower dose escalation, or medication adjustments.
Liver Function and Lipid Panel Tracking
Liver enzymes (AST and ALT) are rechecked at 3 months and 6 months after starting semaglutide or tirzepatide injection therapy. Although serious liver injury is rare with GLP-1 medications, monitoring ensures early detection of any hepatic stress. Patients with nonalcoholic fatty liver disease (NAFLD) may see improvements in liver enzymes as weight loss progresses, which is often visible by month 3.
Lipid panels—measuring total cholesterol, LDL, HDL, and triglycerides—typically improve with GLP-1-mediated weight loss. Many patients see triglyceride reduction within 2–3 months, while LDL cholesterol may stabilize or decrease depending on genetic factors. The PlexusDx Precision Peptide Genetic Test can reveal whether your metabolic pathway favors stronger lipid improvements, helping predict your individual response.
Blood Sugar and Hemoglobin A1C Monitoring
If you have prediabetes or type 2 diabetes, hemoglobin A1C (a 3-month average of blood glucose) is tracked every 3 months while on GLP-1 therapy. Fasting glucose and random glucose checks may also be performed to assess glycemic control. Most patients see A1C reductions of 1–2% within 3 months of semaglutide therapy, with additional improvement continuing through month 6.
Even patients without diabetes benefit from glucose monitoring because GLP-1 medications improve insulin sensitivity. A baseline A1C under 5.7% is healthy, but monitoring ensures your levels remain stable as you lose weight and your medication dose adjusts. Rapid glucose improvement sometimes signals that your dose is optimally calibrated for your physiology.
Pancreatic Enzyme Tests and Safety Screening
Amylase and lipase are pancreatic enzymes occasionally monitored if you report upper abdominal pain or nausea that worsens despite medication adjustments. Although pancreatitis is extremely rare with modern GLP-1 therapy, baseline and as-needed pancreatic enzyme tests provide reassurance. If your amylase or lipase rises above normal range, your provider may pause treatment temporarily to investigate.
Calcitonin, a marker for medullary thyroid cancer, is generally not routinely tested because GLP-1 medications are not linked to human thyroid cancer. However, if you have a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia (MEN) syndrome, your doctor may recommend baseline calcitonin and periodic monitoring.
How PlexusDx Integrates Lab Monitoring Into Your Treatment Plan
PlexusDx compounded semaglutide injection (starting at $149/month) is dispensed through licensed 503A compounding pharmacies across all 50 states. Your healthcare provider partner coordinates baseline labs before your first dose and schedules follow-up testing at 3-month and 6-month marks. PlexusDx does not require insurance or membership fees, and your lab costs are separate from your medication price—your dose may need to go up, but your price won't.
The optional PlexusDx Precision Peptide Genetic Test ($99 add-on after your first month of treatment) analyzes 14 metabolic pathways and 150+ genetic insights, including variants in the GLP1R and GIPR genes. This personalized data helps predict whether you'll have strong glucose control, significant lipid improvements, or enhanced weight loss—allowing your provider to optimize your monitoring schedule and treatment expectations from the start.
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
What lab tests do I need before starting semaglutide?
Before beginning semaglutide injection from PlexusDx, your provider orders a metabolic panel (glucose, electrolytes, kidney and liver function), lipid panel, CBC, and TSH. These baseline results establish your starting point and ensure you don't have contraindications to GLP-1 therapy. All testing is coordinated with your licensed healthcare provider partner.
How often should I get lab work while on GLP-1 medication?
Most patients have labs rechecked at 3 months and 6 months after starting GLP-1 therapy, with emphasis on kidney function, liver enzymes, and glucose control. If you have pre-existing kidney disease or are on multiple medications, your provider may recommend more frequent monitoring. PlexusDx-connected providers tailor the monitoring schedule to your individual risk factors.
Why is kidney function monitored on GLP-1 medications?
GLP-1 drugs can affect hydration and blood pressure, which influence kidney function over time. Nausea and reduced appetite may lower fluid intake, increasing dehydration risk. Regular creatinine and eGFR monitoring ensures your kidneys remain healthy; if levels shift significantly, your provider may recommend increased water intake or slower dose escalation.
Can GLP-1 medications improve my cholesterol levels?
Yes, most patients see triglyceride reductions and stable or declining LDL cholesterol within 2–3 months of starting semaglutide or tirzepatide. Your lipid panel typically shows improvement by month 3 as weight loss progresses. The PlexusDx Precision Peptide Genetic Test reveals whether your metabolic pathways favor especially strong lipid improvements, helping your provider predict your individual response.
Does PlexusDx help coordinate my lab testing?
PlexusDx partners you with a licensed healthcare provider who orders baseline labs before your first semaglutide injection dose and schedules follow-up testing at 3 and 6 months. Lab costs are separate from your medication—PlexusDx's flat-rate pricing ($149–$189/month for semaglutide injection) covers your medication regardless of dose adjustments, with no insurance or membership fees required.
What does the PlexusDx Precision Peptide Genetic Test measure?
The Precision Peptide Genetic Test ($99 add-on after month one) analyzes 14 metabolic pathways and 150+ genetic insights, including key GLP-1 receptor variants (GLP1R rs6923761, GIPR rs1800437) and weight-related genes (FTO, MC4R). This personalized data predicts your likelihood of strong glucose control, lipid improvements, and enhanced weight loss, enabling more precise treatment optimization.
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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