💉 On a GLP-1 (Semaglutide / Tirzepatide)
For everyone · 11 markers · $148.05
with code CAMERON $164.50
Taking or about to start semaglutide, tirzepatide or retatrutide — for weight, metabolic health, or both.
🩸 Order this exact panel — 10% off
All 11 markers load into your cart in one click. No doctor's visit, drawn at any Quest location in the US, results by email in about two weeks. Code CAMERON applies automatically.
Add all 11 markers — $148.05 → Open the full Bloodwork Vault →Why this panel
GLP-1s work, and they carry specific, monitorable risks. Rapid weight loss changes gallbladder, kidney, thyroid and nutrient status, and a large share of the weight lost can be lean mass if protein and training aren't right. This panel tracks efficacy and safety together.
What this panel can settle, and by what logic
Eleven markers split cleanly into three jobs, and reading them in that grouping is what makes the panel worth more than a scale.
- Efficacy: HbA1c (Hemoglobin A1c) with Fasting Insulin. Insulin falls first and fast, within weeks, because energy intake drops before anything structural changes. HbA1c integrates 2 to 3 months Chen 2022, so a falling insulin with a static HbA1c at 6 weeks is the expected pattern rather than a disappointing one.
- Safety: Lipase and the liver and kidney panel on the Comprehensive Metabolic Panel (CMP). Both move with the rate of weight loss rather than with the drug alone, which is why a mid-course draw is more informative than a pre-treatment one.
- Nutrition: Ferritin and Vitamin B12. Eating half as much means absorbing half as much, and monitoring guidance for people on these drugs is being written by borrowing from post-bariatric practice for exactly that reason Sibal 2025. In a menstruating woman the ferritin is the one that falls first.
- ApoB (Apolipoprotein B) beside the Lipid Panel (Cholesterol, HDL, LDL, Triglycerides) confirms the improvement is real. Triglycerides fall dramatically on these drugs, which flatters a calculated LDL cholesterol; ApoB counts particles and does not flatter anything. The cardiovascular and kidney outcome benefits of this class are established in type 2 diabetes Sattar 2021, and ApoB is the marker that tracks the mechanism.
What it cannot settle, and what would
It cannot tell you whether the weight coming off is fat or lean mass, and that is the question this panel is bought to answer. A substantial share of the tissue lost during pharmacological weight loss is fat-free mass, and that literature is now explicit that emerging fat-reduction drugs have to be judged on muscle, bone and hematopoietic outcomes rather than on weight Stefanakis 2024. No blood marker measures body composition. A DEXA scan does, it costs about $75, and one before starting and one at 6 months is the single highest-value test that is not on this list.
IGF-1 (Insulin-like Growth Factor 1) is not a lean-mass proxy. It is on this panel as a nutritional-status signal — it falls with severe energy restriction — and reading a normal IGF-1 as evidence that muscle is being preserved is the specific mistake this page exists to stop Stefanakis 2024. A grip-strength measurement and a scale weight on a working set tell you more.
It cannot detect gallstones, and rapid weight loss causes them. The Comprehensive Metabolic Panel (CMP) will show an obstructed duct after the fact, through bilirubin and ALP. It will not show a stone forming. That is an ultrasound Sibal 2025.
And a normal Lipase does not exclude pancreatitis in somebody with pain. Severe upper abdominal pain radiating to the back is a same-day clinical problem whatever the number said last month Sattar 2021.
Draw conditions that decide whether the money is wasted
Three of these instructions cost you the baseline if you get them wrong, and a baseline cannot be bought retrospectively.
- Draw before the first injection. This is the only unrepeatable purchase on the page. Once the drug is in, the pre-treatment HbA1c (Hemoglobin A1c), ApoB (Apolipoprotein B) and Ferritin are gone, and every later result becomes a number without a comparator.
- At least 48 hours after your weekly dose. Nausea and reduced intake cluster in the first days after an injection, so a draw taken then measures the trough of your eating rather than your steady state.
- Fast 9 to 12 hours. Fasting Insulin and the triglycerides both require it, and on this panel the insulin is the marker that moves earliest.
- Not during an acute illness or within 2 weeks of one. Ferritin rises as an acute-phase protein and will read reassuring at the moment iron stores are actually falling, which is the exact failure mode this marker has on this panel Cancado 2025.
How you would know it answered your question, and what each pattern means next
Baseline, 3 months, 6 months. The intervals are set by which marker has had time to move.
- Fasting Insulin down and HbA1c (Hemoglobin A1c) unchanged at 12 weeks: working as expected. HbA1c reports the preceding 2 to 3 months and lags the insulin by design Chen 2022, so judge the glycemic response at 6 months rather than 3.
- Weight falling fast with IGF-1 (Insulin-like Growth Factor 1) falling and no resistance training: the branch that matters. Raise protein, add lifting, and buy the body-composition scan rather than another panel — the blood work has already told you everything it can about this Stefanakis 2024.
- Ferritin or Vitamin B12 falling between draws: intake, not disease. A serum B12 near the bottom of its interval should be confirmed with Methylmalonic Acid (MMA) before supplementing, because the serum value is a poor guide to functional status on its own Harrington 2024, and ferritin should be re-read against hs-CRP (High-Sensitivity C-Reactive Protein) Cancado 2025.
- Lipase rising with any abdominal pain: stop and see a doctor. This is the only result here that does not wait for the next scheduled draw Sattar 2021.
- Everything improving: drop to annual monitoring once the weight has been stable for 6 months, and keep the ApoB (Apolipoprotein B) in the series — it is the marker whose improvement you want to still be there in 3 years Sattar 2021.
Sources read for these sections
- Stefanakis K, et al. The impact of weight loss on fat-free mass, muscle, bone and hematopoiesis health: Implications for emerging pharmacotherapies aiming at fat reduction and lean mass preservation. Metabolism 2024 · PMID 39481534
- Sibal R, et al. Macronutrient, Micronutrient Supplementation and Monitoring for Patients on GLP-1 Agonists: Can We Learn from Metabolic and Bariatric Surgery?. Nutrients 2025 · PMID 41373949
- Sattar N, et al. Cardiovascular, mortality, and kidney outcomes with GLP-1 receptor agonists in patients with type 2 diabetes: a systematic review and meta-analysis of randomised trials. Lancet Diabetes and Endocrinology 2021 · PMID 34425083
- Chen Z, et al. Interpretation of HbA1c lies at the intersection of analytical methodology, clinical biochemistry and hematology (Review). Experimental and Therapeutic Medicine 2022 · PMID 36382101
- Harrington DJ. The application and interpretation of laboratory biomarkers for the evaluation of vitamin B12 status. Annals of Clinical Biochemistry 2024 · PMID 39367523
- Cancado RD. Defining Global Thresholds for Serum Ferritin: A Challenging Mission in Establishing the Iron Deficiency Diagnosis in This Era of Striving for Health Equity. Diagnostics (Basel) 2025 · PMID 39941219
The 11 markers — and why each one is here
Liver, kidney, electrolytes — all move with rapid weight loss
Falls with visceral fat loss — a good progress marker
Ordering the panel tells you your numbers. The protocol tells you what to do with them — how much of the weight you lose is muscle and what the trials show actually prevents it, the monitoring nobody mentions, the exit plan for when you stop, and the one popular peptide that works against the drug you're paying for.
Join Skool — $10/mo →What this panel is ordered to decide
A panel is a set of numbers until it settles something. These are the decisions this one feeds — each links the pathway it belongs to, what that pathway claims, and what its test list is read for.
Muscle loss on an aggressive deficit is invisible on the scale and obvious in IGF-1 and testosterone, both of which fall in a sustained deficit. Worth a baseline before you start and a recheck at eight weeks — this is the panel built specifically for people running a GLP-1.
The monitoring panel for anyone on a GLP-1. Lipase and amylase are there for the pancreatitis signal, and thyroid because of the medullary carcinoma contraindication — both are on the label and rarely tracked.
Related panels
Frequently asked questions
11 markers: HbA1c (Hemoglobin A1c), Insulin (Fasting), Comprehensive Metabolic Panel (CMP), Lipase, Lipid Panel, ApoB (Apolipoprotein B), IGF-1 (Insulin-like Growth Factor 1), TSH (Thyroid-Stimulating Hormone), Ferritin, Vitamin B12, hs-CRP (C-Reactive Protein, High Sensitivity).
$164.50 before discount, $148.05 with code CAMERON applied automatically. Individual markers add a one-time $10 draw fee. Ordered through Marek Diagnostics and drawn at any Quest Diagnostics location in the US.
No. These are ordered direct-to-consumer through Marek Diagnostics — you order online, walk into a Quest location, and results are emailed to you in about two weeks. No physician visit or insurance required. Not available in NY, NJ or RI.
Baseline before starting, then at 3 months and 6 months. Fast 9–12 hours. Draw at least 48 hours after your injection if you're on a weekly protocol.
Falling HbA1c and fasting insulin = it's working metabolically. Rising lipase with abdominal pain → stop and see a doctor. Falling IGF-1 with rapid loss → increase protein and add resistance training. Watch ferritin and B12 — reduced food intake means reduced nutrient intake.
Where this goes next
This page is how to read the panel. What to DO about each result — the dosing, the order to correct things in, the week-by-week schedule and what to retest — is a lesson inside Skool.