Educational guide for research and informational purposes only. Not medical advice.
Running peptide protocols without baseline bloodwork is guesswork. You have no way to know whether the compounds are producing the intended effect, whether biomarkers are trending in the right direction, or whether there are early warning signs that require protocol adjustment. This guide covers which labs to run, when to run them, what markers are relevant for each compound class, and how to interpret what you see — so your protocol decisions are based on data, not assumptions.
The Core Principle: Baseline Before You Start
Every biomarker has meaning only in context. A fasting glucose of 102 mg/dL means something very different if your baseline was 95 vs. 115. An IGF-1 of 280 ng/mL may be appropriate optimization if you started at 150, or potentially supraphysiologic if you started at 260. Without a baseline, you cannot evaluate response or safety.
This applies regardless of which compounds you're running. The principle is universal: know where you are before you intervene, so you know whether the intervention is moving you in the right direction.
Lab Panel by Protocol Type
GLP-1 / Weight Loss Protocols
If you're using semaglutide, tirzepatide, retatrutide, or any GLP-1-class compound, these are the essential markers:
Baseline (before starting):
- HbA1c — glycated hemoglobin; reflects average blood glucose over 3 months; establishes your glycemic baseline and is the primary efficacy marker for glucose control
- Fasting glucose — acute glycemic status; should be tested fasted (8–12 hours)
- Fasting insulin — combined with fasting glucose to calculate HOMA-IR (insulin resistance index); often more informative than glucose alone
- Lipid panel (total cholesterol, LDL, HDL, triglycerides, non-HDL cholesterol) — cardiovascular risk baseline; GLP-1 therapy typically improves triglycerides and HDL; tracking this confirms metabolic effect
- Comprehensive metabolic panel (CMP) — includes liver enzymes (ALT, AST), kidney function (creatinine, BUN, eGFR), electrolytes, total protein, albumin
- Thyroid (TSH, Free T3, Free T4) — thyroid function affects weight loss rate and GLP-1 response; C-cell tumor risk with GLP-1 agents makes baseline thyroid status relevant
- CBC (complete blood count) — baseline hematologic status
- Amylase and lipase — pancreatic enzymes; relevant given the labeled pancreatitis risk with GLP-1 agents; abnormal baseline values are a contraindication signal
Follow-up (12–16 weeks into protocol):
- HbA1c — confirms glycemic trend
- Fasting glucose and insulin — acute glycemic response verification
- Lipid panel — confirms expected triglyceride reduction and HDL improvement
- ALT/AST — liver enzyme monitoring; GLP-1 agents are generally hepatoprotective, but any compound affecting caloric intake and metabolism warrants monitoring
- Kidney function (creatinine, eGFR) — dehydration during early GLP-1 use can transiently affect kidney function
Products: Weight Loss Lab Panel | Weight Loss Follow-Up Panel
GH Axis Protocols (CJC-1295, Ipamorelin, Tesamorelin, Sermorelin)
Growth hormone secretagogue protocols require monitoring of the GH/IGF-1 axis and potential metabolic effects of elevated GH.
Baseline:
- IGF-1 (insulin-like growth factor 1) — the primary proxy for GH axis activity; more stable than GH itself (half-life of hours vs. minutes for GH); age-adjusted reference ranges are essential for interpretation
- Fasting glucose and HbA1c — GH has counter-regulatory effects on insulin; elevated GH impairs insulin sensitivity; baseline glycemic status is essential
- Fasting insulin — HOMA-IR calculation
- Lipid panel — GH axis optimization typically improves lipid profile; baseline enables tracking
- TSH — thyroid function influences GH axis responsiveness
- Cortisol (AM, fasted) — establishes HPA axis baseline; some GHRPs affect cortisol (less relevant with Ipamorelin, more relevant with GHRP-2/6)
Follow-up (12 weeks):
- IGF-1 — primary efficacy marker; should rise 30–60% from baseline with effective GH secretagogue protocol; supraphysiologic elevation (>3 SD above age-adjusted mean) is a signal to reduce dose
- Fasting glucose and HbA1c — GH-mediated insulin resistance monitoring
- Lipid panel — confirms expected improvements
TRT / Hormonal Protocols
Testosterone replacement and related hormonal protocols require the most comprehensive monitoring framework.
Baseline:
- Total testosterone — the primary hormone being replaced or optimized
- Free testosterone — biologically active fraction; more clinically relevant than total in many contexts
- SHBG (sex hormone-binding globulin) — determines free testosterone fraction; high SHBG means less bioavailable testosterone even at adequate total levels
- LH and FSH — pituitary signals to the gonads; establish whether hypogonadism is primary (testicular) or secondary (pituitary/hypothalamic) — critical for choosing the right intervention
- Estradiol (sensitive assay for males) — testosterone aromatizes to estradiol; monitoring prevents both excessive estrogen effects and over-suppression
- Hematocrit and hemoglobin — testosterone stimulates erythropoiesis; elevated hematocrit increases clotting risk and is a common reason for dose adjustment
- Prostate-specific antigen (PSA) — baseline for men over 40; testosterone does not cause prostate cancer, but can stimulate existing occult cancer
- Complete metabolic panel — liver and kidney baseline
- Lipid panel — TRT effects on lipids are complex (may reduce HDL with some formulations)
- Thyroid panel — thyroid dysfunction mimics and worsens hypogonadism symptoms
- Cortisol — adrenal function assessment
- Prolactin — elevated prolactin is a common cause of secondary hypogonadism and libido issues
Follow-up (6–12 weeks after initiation or dose change):
- Total and free testosterone, SHBG — confirms target range achievement
- Estradiol — monitors aromatization
- Hematocrit and hemoglobin — safety monitoring; intervention required if hematocrit >52–54%
- PSA — annual minimum after baseline
- LH and FSH — if fertility is a concern (to confirm suppression level and guide co-therapy decisions)
Longevity and Anti-Aging Protocols
Comprehensive baseline:
- All of the above, plus:
- Inflammatory markers: hs-CRP, IL-6, TNF-α — systemic inflammation is a primary driver of biological aging ("inflammaging")
- Homocysteine — independent cardiovascular and cognitive risk marker; elevated with B vitamin deficiency; relevant to NAD+ and methylation-focused protocols
- Ferritin — iron storage; elevated ferritin is pro-inflammatory and pro-oxidative; low ferritin impairs energy production and cognitive function
- Vitamin D (25-OH) — immune modulation, testosterone signaling, calcium regulation; nearly universally suboptimal in modern populations
- DHEA-S — adrenal androgen; declines with age; marker of adrenal reserve and biological aging rate
- Biological age testing (telomere length, epigenetic clock) — optional but increasingly available; provides the most direct measure of aging trajectory
Interpreting Results — Practical Framework
IGF-1 (GH Axis Protocols)
- Age 20–30: 180–300 ng/mL typical reference range
- Age 40–50: 120–220 ng/mL typical
- Age 60+: 80–160 ng/mL typical
- Target on GH secretagogue protocol: optimize to upper quartile of age-adjusted range; avoid sustained levels above upper limit of young adult range (>300–350 ng/mL)
Testosterone (TRT)
- Most labs define normal male range as 264–916 ng/dL; this range is statistically derived and includes men with symptomatic hypogonadism at the low end
- Optimization target: typically 600–900 ng/dL total; free testosterone in upper third of reference range
- SHBG-adjusted interpretation: a man with total T of 600 ng/dL and SHBG of 60 nmol/L may have lower free testosterone than a man with total T of 450 and SHBG of 20
Fasting Glucose and HbA1c
- Fasting glucose: optimal <90 mg/dL; prediabetes range 100–125 mg/dL; diabetes ≥126 mg/dL
- HbA1c: optimal <5.4%; prediabetes 5.7–6.4%; diabetes ≥6.5%
- On GLP-1 therapy: expect reduction toward optimal range; if HbA1c is rising on GLP-1 therapy, investigate compliance, dosing, and dietary context
Testing Timeline Summary
| Protocol Type | Baseline | First Follow-Up | Ongoing |
|---|---|---|---|
| GLP-1 / Weight Loss | Before Day 1 | 12–16 weeks | Every 6 months |
| GH Secretagogues | Before Day 1 | 12 weeks | Every 6 months |
| TRT | Before Day 1 | 6–8 weeks | Every 3–6 months (first year) |
| Longevity Stack | Before Day 1 | 12 weeks | Every 6–12 months |
Starting Point
- Weight Loss Lab Panel — comprehensive baseline for GLP-1 and body composition protocols
- Weight Loss Follow-Up Panel — monitoring at 12–16 weeks
- Doctor's Consultation — to review your results and build a protocol based on your specific biomarker profile
References
- Boehm BO, et al. Monitoring of IGF-1 in Clinical Practice. Horm Metab Res. 2014;46(5):315–322.
- Bhasin S, et al. Testosterone Therapy in Men with Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(5):1715–1744.
- American Diabetes Association. Standards of Medical Care in Diabetes. Diabetes Care. 2024;47(Suppl 1).
- Veldhuis JD, et al. Age, Sex, and Body Composition as Predictors of GH and IGF-1 Axis Activity. J Clin Endocrinol Metab. 2005.
- Loh HH, et al. Interpretation of Testosterone Levels in the Context of SHBG. Clin Endocrinol. 2020;92(4):315–323.
Educational Disclaimer: This content is for educational and informational purposes only and does not constitute medical advice. Consult a qualified healthcare provider to interpret your specific laboratory results.
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