Every peptide protocol should start with a baseline lab panel. This guide explains which biomarkers matter, what the numbers mean, and how to use them to build a protocol that fits your actual biology.
Most platforms ask what your goal is. We start where the science starts, with what your body is actually doing right now.
Without baseline labs, you have no objective way to know whether a protocol is working, what's changing, or whether something is moving in the wrong direction. Your baseline is the starting line.
Certain biomarker patterns, elevated IGF-1, suppressed cortisol, metabolic dysfunction, can make specific peptides inappropriate or outright risky. Labs reveal what the mirror doesn't.
In research contexts, labs are often repeated periodically so changes in markers such as IGF-1, inflammation, or hormones can be tracked as a trend over time. A provider decides on any repeat testing and how to interpret it.
Click any marker to expand the full guide, what it measures, why it is a useful baseline, and which peptide categories it informs.
Reference ranges for IGF-1 vary by laboratory, assay, age, and sex. Read your result against your lab's printed reference range, and review it with a provider. A single value matters less than a baseline tracked over time. See the full IGF-1 guide for deeper reference context.
IGF-1 is a common baseline marker in research involving GH secretagogues, including Ipamorelin, CJC-1295, Sermorelin, and Epithalon. Research suggests IGF-1 reflects overall GH-axis activity, which is why establishing a baseline and reviewing it with a provider is part of a careful, test-first approach.
Reference ranges for total and free testosterone vary by laboratory, assay, age, and sex. Read your result against your lab's printed reference range, and review it with a provider. A baseline tracked over time is more informative than a single reading. See the full testosterone guide for deeper reference context.
GH secretagogues like Ipamorelin, CJC-1295, and Sermorelin are studied in the context of the broader hormonal picture. A baseline testosterone reading gives context that helps a provider interpret symptoms and the full hormone panel rather than any single marker in isolation.
Cortisol follows a daily rhythm, so timing matters, and reference ranges vary by laboratory, assay, and time of draw. Read your result against your lab's printed reference range, and review it with a provider. See the full cortisol guide for deeper reference context.
Some GH secretagogues, particularly GHRP-class compounds, have been studied for effects on cortisol release; Ipamorelin is generally described in research as having minimal cortisol stimulation compared with other GHRPs. A cortisol baseline gives a provider context for interpreting the wider picture.
Reference ranges for hsCRP vary by laboratory and assay, and a single reading can be affected by recent infection or injury. Read your result against your lab's printed reference range, and review it with a provider. See the full hs-CRP guide for deeper reference context.
hsCRP is a common baseline in research involving compounds studied in inflammatory contexts, such as BPC-157, TB-500, and Thymosin Alpha-1. Research suggests hsCRP reflects low-grade systemic inflammation, which is one variable a provider may weigh when interpreting other markers.
Reference ranges for fasting insulin and glucose (and the HOMA-IR calculated from them) vary by laboratory, assay, and clinical context. Read your results against your lab's printed reference range, and review them with a provider. See the fasting insulin and fasting glucose guides for deeper reference context.
GH secretagogues such as Ipamorelin and CJC-1295 have been studied for transient effects on insulin sensitivity, while GLP-1 receptor agonists like Semaglutide and Tirzepatide are studied in metabolic contexts. A fasting insulin and glucose baseline gives a provider context for interpreting the metabolic picture.
Reference ranges and category cutoffs for 25-OH vitamin D vary by source, laboratory, and assay. Read your result against your lab's printed reference range, and review it with a provider. See the full vitamin D guide for cited public reference examples and deeper context.
Vitamin D functions as a steroid-hormone precursor with receptors across many cell types, and it is a common baseline in research involving immune-modulating compounds such as Thymosin Alpha-1. A vitamin D baseline gives a provider context for interpreting the wider picture.
Reference ranges for TSH vary between laboratories and assays, and there is no single universal cutoff. Read your result against your lab's printed reference range, and review it with a provider. A full thyroid panel (TSH with Free T3, Free T4, and anti-TPO) gives a provider more context. See the full TSH guide for deeper reference context.
Thyroid status is part of the context in which other markers are read. Research suggests thyroid function influences the GH axis, so a TSH baseline (ideally with a full thyroid panel) gives a provider context for interpreting symptoms such as fatigue that overlap across several systems.
HbA1c reflects average blood glucose over roughly the prior 2–3 months, and category cutoffs are defined by clinical bodies; reference context can vary by laboratory and by conditions affecting red blood cells. Read your result against your lab's printed reference range, and review it with a provider. See the full HbA1c guide for cited reference context.
HbA1c is a common baseline in research involving GLP-1 receptor agonists like Semaglutide or Tirzepatide, and in GH-secretagogue research where glucose metabolism is a relevant variable. A baseline gives a provider context for interpreting the metabolic picture over time.
Not sure where to start? Here are three panel tiers based on where you are in your research journey.
Several options exist depending on your insurance coverage, location, and how much detail you want.
Most basic panels are covered by insurance. Ask specifically for the Tier 1 markers, many are standard annual bloodwork. Limitation: physicians may not order less common markers without a clinical indication.
Services like Ulta Lab Tests, Walk-In Lab, and LabCorp's direct service allow ordering without a doctor. No insurance, you pay out of pocket. Cost-effective for comprehensive panels, typically $100-400 for full Tier 2.
Clinics like Marek Health, Function Health, and Precision Health specialize in comprehensive panels with clinical interpretation. Best option if you plan to actually use findings to build a supervised protocol.
Always work with a licensed clinician to interpret your results and determine appropriateness of any peptide protocol. Lab values provide context, a qualified clinician provides the clinical judgment. This guide is for educational purposes only.