The bloodwork guide
The labs people on TRT, GLP-1, or peptide protocols tend to track — what each marker is and why it's followed. This explains the panels; it does not interpret your results or set targets. That's your clinician's job.
Why baseline and follow-up labs matter
A baseline before starting anything, then periodic follow-ups, is what lets you and a clinician see real change instead of relying on how you feel. It also catches the side effects that don't announce themselves — a rising hematocrit, for example. PepCue lets you log results and watch the trend; interpreting them is a clinical job.
The common markers
- Total & free testosterone. The primary markers for TRT; free is the unbound, active fraction.
- Estradiol (E2). Some testosterone converts to estradiol; it's followed because both too-low and too-high cause symptoms.
- CBC / hematocrit. TRT can raise red-cell mass; hematocrit is a key safety check.
- Lipids & metabolic panel. General cardiovascular and metabolic health, relevant to GLP-1 and hormone therapy.
- PSA. Prostate marker followed in older men on testosterone.
- IGF-1. Downstream of growth-hormone signalling; relevant to GH-axis peptides.
- HbA1c / glucose. Average blood sugar — central for GLP-1 and metabolic goals.
Frequently asked questions
What bloodwork should I get on TRT?
Clinicians commonly follow total and free testosterone, estradiol, and a complete blood count (for hematocrit), often with lipids, a metabolic panel, and PSA in older men. The exact panel and timing are set by your clinician — this guide explains what each marker is, not which to order or what your number should be.
Why is hematocrit important on testosterone?
Testosterone can increase red-blood-cell production, raising hematocrit. A high hematocrit is a recognized safety concern, which is why a CBC is a standard follow-up lab on TRT. Any action based on the value is a clinical decision.
When should I draw my labs?
Timing matters: for injected testosterone, trough vs peak gives very different numbers, and metabolic markers differ fasting vs fed. The key is consistency so the trend is comparable. Record the draw time with each result.
Do I need labs for peptides too?
It depends on the compound and your goals. GH-axis peptides may make IGF-1 relevant; metabolic peptides and GLP-1s make glucose/HbA1c relevant. Defining one or two objective measures before starting is the evidence-first approach — see the peptide guide.
Sources
- [1]Bhasin S et al. — Testosterone Therapy in Men With Hypogonadism: Endocrine Society Clinical Practice Guideline (monitoring) — J Clin Endocrinol Metab, 2018
- [2]Testosterone therapy and hematocrit / erythrocytosis — peer-reviewed literature — PubMed / NCBI
- [3]IGF-1 as a marker of GH status — peer-reviewed literature — PubMed / NCBI
Links resolve to authoritative search or landing pages (PubMed, FDA / DailyMed). See the full source library and methodology.
Track your protocol in PepCue
Log doses, run the calculators, follow the evidence, and keep peptides, GLP-1s, TRT and labs in one private timeline.
Start here →Educational and research reference only. Not medical advice, diagnosis, or dosing guidance.