Lab Work Guide
The right labs before and during peptide therapy ensure safety, guide dosing, and help you measure results. Here is what to test and what your numbers mean.
Why Lab Work Matters
Baseline
Know where you're starting so you can measure real changes — not just how you feel.
Safety
Catch contraindications early. Some peptides shouldn't be used with certain lab profiles.
Optimization
Your physician adjusts your protocol based on lab response — not guesswork.
Essential Baseline Labs
These panels should be drawn before starting any peptide protocol.
Complete Metabolic Panel (CMP)
What it tests: Liver enzymes (AST, ALT), kidney function (BUN, creatinine), glucose, electrolytes
Establishes organ function baseline. Some peptides are metabolized by the liver — your physician needs to confirm safe function before prescribing.
Complete Blood Count (CBC)
What it tests: Red blood cells, white blood cells, hemoglobin, hematocrit, platelets
Growth hormone peptides can affect red blood cell production. CBC monitors for polycythemia and ensures immune markers are normal.
Hormone Panel
What it tests: Total & free testosterone, estradiol, DHEA-S, cortisol, thyroid (TSH, free T3, free T4)
Core panel for anyone considering GH peptides, sexual health peptides (PT-141, Kisspeptin), or metabolic protocols. Identifies hormonal deficiencies driving your symptoms.
IGF-1 (Insulin-like Growth Factor)
What it tests: Serum IGF-1 level
The primary marker for growth hormone activity. Essential before and during GH-releasing peptide protocols (CJC-1295, Ipamorelin, Sermorelin, MK-677). Your physician will titrate dosing based on this.
Fasting Insulin & Glucose
What it tests: Fasting insulin, fasting glucose, HbA1c
GH peptides can affect insulin sensitivity. MK-677 in particular may elevate fasting glucose. Monitors metabolic health throughout treatment.
Lipid Panel
What it tests: Total cholesterol, LDL, HDL, triglycerides
Metabolic peptides like AOD-9604 and GLP-1 agonists directly impact lipid profiles. Tracks cardiovascular risk markers.
Situational Labs
Your physician may order these based on your specific protocol and health history.
Inflammatory Markers
Tests: CRP (C-reactive protein), ESR, homocysteine
When: If using BPC-157, TB-500, or immune peptides (Thymosin Alpha-1). Tracks inflammation reduction over time.
GH Stimulation Test
Tests: Growth hormone level pre/post stimulation
When: If suspected GH deficiency. Confirms clinical need for GH-releasing peptides rather than empiric prescribing.
Prolactin
Tests: Serum prolactin
When: If using GHRP-6 or other peptides that may elevate prolactin. Also relevant for sexual health protocols.
PSA (men over 40)
Tests: Prostate-specific antigen
When: Before GH peptide therapy in men. GH/IGF-1 elevation requires monitoring of prostate markers.
Gut Health Panel
Tests: Comprehensive stool analysis, zonulin, calprotectin
When: If using BPC-157 or KPV for gut healing protocols. Establishes baseline intestinal permeability and inflammation.
Standard vs. Optimal Ranges
Standard lab reference ranges are designed to detect disease — not optimize health. Functional medicine practitioners target tighter “optimal” ranges for performance and longevity.
| Marker | Standard Range | Optimal Range | Note |
|---|---|---|---|
| IGF-1 | 53-331 ng/mL | 200-280 ng/mL | Target upper-mid range for GH peptide users |
| Total Testosterone (M) | 264-916 ng/dL | 600-900 ng/dL | Optimal for energy, recovery, body composition |
| Free Testosterone (M) | 8.7-25.1 pg/mL | 15-25 pg/mL | The biologically active fraction |
| Fasting Insulin | 2.6-24.9 uIU/mL | 3-8 uIU/mL | Lower is better for metabolic health |
| Fasting Glucose | 70-100 mg/dL | 75-90 mg/dL | Monitor closely on MK-677 |
| HbA1c | <5.7% | <5.2% | Long-term glucose control |
| CRP | <3.0 mg/L | <1.0 mg/L | Systemic inflammation marker |
| TSH | 0.45-4.5 mIU/L | 1.0-2.5 mIU/L | Thyroid function — midrange is ideal |
These ranges are guidelines for discussion with your physician. Individual targets may vary based on age, sex, health history, and specific peptide protocol.
Get Started With Your Protocol
Build your personalized protocol and get matched with a physician who will order the right labs and guide your therapy.