Blood work on GH peptides — what to test and when

If you're running GH secretagogue research without blood work, you're flying blind. Here's exactly what to test, when to test it, and how to interpret the results.

Baseline blood work (before starting any GH peptide):
IGF-1 — this is the primary marker. Growth hormone itself is pulsatile and difficult to measure accurately with a single blood draw. IGF-1 is produced by the liver in response to GH and provides a stable, reliable indicator of your overall GH status. Get this tested fasted, in the morning. Normal range varies by age, but typical adult range is 100-300 ng/mL.

Fasting glucose and HbA1c — GH peptides can affect insulin sensitivity. You need a baseline to track any changes. Fasting insulin — more sensitive than glucose alone for detecting early insulin resistance changes. Thyroid panel (TSH, Free T3, Free T4) — GH and thyroid hormones interact. Some researchers report thyroid changes during extended GH peptide protocols. Comprehensive metabolic panel — liver and kidney markers, electrolytes. Baseline for safety monitoring.

Follow-up testing schedule:
4-6 weeks after starting: Retest IGF-1. This is your primary efficacy check. A meaningful increase (20-50% above baseline) suggests the protocol is working. If IGF-1 hasn't moved, reassess your peptide quality, dosing, timing, and fasting compliance.

8-12 weeks: Full panel retest including glucose, insulin, and thyroid. This catches any metabolic shifts that develop over time.

Every 3 months during extended protocols: Repeat the full panel. GH peptide research is generally well-tolerated, but monitoring is responsible practice.

Interpreting IGF-1 results:
Modest increase (10-20% above baseline): Peptide is likely working but protocol optimization may help. Consider adjusting timing, ensuring fasting compliance, or adjusting dose.
Significant increase (20-50% above baseline): Protocol is working well. This is the target range for most researchers.
No change: Either the peptide quality is poor, the dose is too low, timing/fasting isn't right, or you're a non-responder (rare but possible).
Excessive increase (IGF-1 above 350-400 ng/mL): Consider reducing dose. Chronically elevated IGF-1 has its own risk profile.

Common mistakes:
Testing GH directly instead of IGF-1 — a single GH blood draw is nearly meaningless because of pulsatile secretion. Getting blood drawn in the afternoon — IGF-1 and most hormones should be tested fasted, in the morning, for consistency. Not getting baseline blood work — without a starting point, your follow-up numbers mean nothing. Testing too early — give it at least 4 weeks before expecting measurable IGF-1 changes.

Where to get blood work:
Many researchers use direct-to-consumer lab services that don't require a doctor's order. An IGF-1 test alone typically costs $50-80. A comprehensive hormone panel with IGF-1, metabolic markers, and thyroid runs $150-300 depending on the service.