15 key biomarkers explained in plain language , what they measure, what optimal looks like, and why they matter before any peptide research. Test first. Always.
Without baseline labs you have no way to know what's changing, what's working, or what needs attention. Numbers give your research context it can't have without them.
Certain biomarker patterns make specific peptide research inappropriate or higher risk. Labs reveal what symptoms can't , and often point to a different root cause entirely.
Repeat labs at 8–12 week intervals give you objective data instead of guesswork. Without before-and-after measurements, you have no way to evaluate what your research is doing.
Insulin-like Growth Factor-1
"Your body's main signal for growth hormone activity , think of it as the readout that shows whether your GH system is working."
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Learn More →Total & Free Testosterone
"The primary androgenic hormone , affects energy, body composition, recovery, libido, and mood in both men and women."
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Learn More →AM Serum Cortisol
"Your main stress hormone , it follows a daily rhythm, peaking in the morning. Think of it as your body's internal alarm system readout."
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Learn More →High-Sensitivity C-Reactive Protein
"A liver protein that rises when there's inflammation in the body , high hsCRP means your immune system is working hard on something."
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Learn More →Fasting Serum Insulin
"How much insulin your body needs to keep blood sugar stable when you haven't eaten , high levels mean your cells are becoming resistant to insulin's signal."
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Learn More →Fasting Blood Glucose
"Your blood sugar level after not eating , the most basic snapshot of how your body manages sugar."
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Learn More →Glycated Hemoglobin
"A 3-month average of your blood sugar , more reliable than a single glucose reading because it shows the bigger pattern."
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Learn More →25-OH Vitamin D
"Often called the sunshine vitamin , but it works more like a hormone, affecting immune function, mood, testosterone, and bone health all at once."
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Learn More →Thyroid Stimulating Hormone
"The signal your brain sends to your thyroid , high TSH means the thyroid isn't responding enough, low TSH means it may be overactive."
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Learn More →Sex Hormone Binding Globulin
"A protein that binds to testosterone and makes it unavailable , high SHBG means even normal total testosterone may not be doing its job."
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Learn More →Luteinizing Hormone & Follicle Stimulating Hormone
"The brain signals that tell your body to produce testosterone and manage reproductive function , they reveal whether a hormone problem starts in the brain or the glands."
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Learn More →Estradiol (E2)
"The primary estrogen hormone , important for both men and women for bone density, mood, cardiovascular health, and hormonal balance."
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Learn More →Apolipoprotein B
"A more precise measure of cardiovascular risk than standard LDL , it counts the actual number of harmful lipoprotein particles, not just their weight."
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Learn More →Dehydroepiandrosterone Sulfate
"A hormone produced by the adrenal glands that declines steadily with age , often called a biological age marker."
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Learn More →Plasma Homocysteine
"An amino acid byproduct that builds up when methylation pathways aren't working well , elevated levels are linked to cardiovascular and cognitive risk."
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Learn More →Three tiers of testing , ordered by what's needed before each stage of research. Work through them in sequence with a licensed healthcare provider.
hsCRP · Fasting Glucose · Fasting Insulin · HbA1c · TSH · Vitamin D · Comprehensive Metabolic Panel · CBC with diff
"This panel gives you the metabolic, inflammatory, and thyroid context needed for any peptide category."
IGF-1 · Total & Free Testosterone · SHBG · LH & FSH · Estradiol · AM Cortisol · Free T3 · Free T4 · Anti-TPO
"Required before Ipamorelin, CJC-1295, Sermorelin, or any GH secretagogue research."
ApoB · DHEA-S · Homocysteine · Ferritin · Omega-3 Index · Uric Acid · NAD+ levels
"For those working with a longevity or functional medicine clinician on a multi-peptide protocol."
The Lab Testing Guide explains exactly how to prepare, what to order, and how to read your results in the context of peptide research.