Drawing labs at the wrong time relative to your protocol makes results uninterpretable. This guide covers exactly when to draw each key marker for every major peptide category.
Quick Summary - IGF-1 must be drawn fasted, morning, 24-36 hours after your last GH peptide dose -- the most common timing mistake in the space - Hormone panels (testosterone, LH, FSH, estradiol) should be drawn fasted, morning, regardless of enclomiphene timing - GLP-1 users draw 48 or more hours after weekly injection for the most stable metabolic readings - BPC-157 and TB-500 have no timing requirements -- draw hs-CRP and other indirect markers at any fasted morning draw - A baseline draw before starting any protocol is non-negotiable
It is not forgetting to order ApoB. It is not skipping the baseline. It is drawing labs at the wrong time relative to their protocol and getting numbers that do not reflect their actual steady-state biology.
IGF-1 drawn two hours after a tesamorelin injection can be 40-60% higher than the true baseline IGF-1. Testosterone drawn at 4pm instead of morning can be 20-25% lower than the morning value. Fasting glucose drawn two hours after eating is measuring something completely different than fasting glucose.
These errors lead to wrong conclusions, wrong dose adjustments, and wrong assessments of whether a protocol is working. Timing is not a detail -- it is foundational to making your lab data meaningful.
IGF-1 is produced by the liver in response to GH pulses. When you take a GH peptide (tesamorelin, ipamorelin, CJC-1295, sermorelin), it drives a GH pulse, which drives an IGF-1 surge. This post-dose IGF-1 elevation is temporary -- it reflects the immediate GH effect, not your steady-state IGF-1 level.
Draw timing for IGF-1:
For daily GH peptide users: skip one dose, draw the next morning.
For twice-daily users: skip the morning dose, draw that morning (approximately 12 hours post last dose -- borderline acceptable) or skip an entire day and draw the following morning.
Testosterone follows a diurnal rhythm -- highest in the morning (around 8-10 AM) and declining throughout the day by 20-25% or more by afternoon. All hormone studies use morning values for this reason.
Draw timing for testosterone, LH, FSH, estradiol, SHBG:
For users on TRT or other exogenous testosterone: the timing relative to injection matters significantly. Consult with your prescribing physician for the appropriate draw window for your specific protocol.
Both semaglutide and tirzepatide are weekly medications with half-lives of 7 days (semaglutide) and 5 days (tirzepatide). Drug levels are relatively stable week-to-week, but the first 24-48 hours after injection show slightly higher drug concentration and slightly more pronounced metabolic effects.
Draw timing for GLP-1 users:
Neither BPC-157 nor TB-500 has a direct serum marker that is meaningfully affected by injection timing. The indirect markers you track (hs-CRP, IGF-1, liver enzymes) follow their own timing rules independent of BPC-157 or TB-500 administration.
Draw timing for BPC-157 and TB-500 indirect markers:
Regardless of which markers you are drawing or which protocol you are on, these rules apply to every blood draw:
Fast for at least 8 hours. Water is fine. Coffee is not.
Draw in the morning (7-10 AM for most markers).
Avoid intense exercise within 24 hours of your draw -- exercise elevates many markers including glucose, cortisol, and certain enzymes.
Avoid alcohol for 48 hours before drawing liver enzymes specifically.
Avoid biotin supplementation for 72 hours before any draw -- biotin interferes with multiple immunoassay tests including thyroid, sex hormones, and other markers.
For a comprehensive peptide protocol, here is a standard schedule:
Baseline (before any protocol): Full panel -- IGF-1, complete hormone panel, metabolic panel, lipids including ApoB, hs-CRP, CBC, liver enzymes, kidney function, thyroid, nutrients.
Week 6-8: IGF-1 (first GH response check), fasting glucose and HbA1c (metabolic response), testosterone and LH if on HPG axis support.
Week 12: Full Tier 1 panel -- IGF-1, hormone panel, ApoB, HbA1c, fasting glucose, hs-CRP, liver enzymes.
Every 6 months (ongoing): Full panel recheck. Add or subtract markers based on 12-week findings.
Enter your draw dates, protocol details, and biomarker values in MyProtocolStack. Log the timing of your draw relative to your last dose -- this context makes StackAI analysis more accurate and helps you compare apples to apples across multiple draws.
The information in this article is for educational purposes only. It does not constitute medical advice. Always consult a licensed healthcare provider before starting any peptide protocol.
Written by Ryan -- Founder, MyProtocolStack. Last Updated: April 2026.
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