How to Interpret Your IGF-1 Results on a GH Peptide Protocol

What IGF-1 Measures

IGF-1 is a hormone produced primarily by the liver in response to growth hormone signaling. GH itself is pulsatile-it spikes and drops throughout the day-making it impractical to measure. IGF-1 is stable and integrates your overall GH production, giving a clear picture of your GH status over days and weeks.

Think of IGF-1 as a "GH output meter"-higher IGF-1 means your body produced more GH over the preceding 2-4 weeks.

Age-Based Optimal Ranges

IGF-1 naturally declines with age. Optimal ranges are age-dependent:

Lab reference ranges often show a broader "normal" (80-240 ng/mL for adults), but for someone running GH-releasing peptides, aiming for the upper 40-60% of your age-appropriate range is typical. This represents enhanced GH signaling without excessive levels.

When to Draw and How Timing Affects Results

Timing relative to GH peptide injections matters significantly:

GH peptides take 2-4 weeks to elevate IGF-1 noticeably. Your first draw at week 2 may show minimal change; week 6-8 is when meaningful elevation appears. If you're testing too early or after only 1-2 weeks of protocol, don't expect dramatic changes.

Interpreting Your Results: The Decision Tree

Result: Within age-appropriate normal range (60-80th percentile)

Result: Below age-appropriate range (below 50th percentile)

Result: Well above age-appropriate range (90th+ percentile)

Result: Extreme elevation (>350 ng/mL in adults under 50)

The Dose-Response Relationship

IGF-1 generally shows a dose-response curve: more GH peptide (up to a point) produces higher IGF-1. However, this isn't perfectly linear:

Your dose should fall into the "sweet spot" where you're raising IGF-1 meaningfully without overshooting into problematic territory.

What High vs Low IGF-1 Means Long-Term

Consistently elevated IGF-1 (in the 75-90th percentile for your age) correlates with:

Consistently low IGF-1 (below 50th percentile) suggests:

Retesting and Adjustment Timeline

1. Start protocol: Baseline IGF-1 test before beginning

2. Week 4-6: Retest (expecting minimal change, establishing early response)

3. Week 8-10: Retest (expect meaningful elevation if dose is adequate)

4. Weeks 12+: Test every 8-12 weeks to monitor stability and guide dose adjustments

5. If changing dose: Retest 4 weeks after adjustment

Frequent testing (weekly or monthly) is unnecessary and expensive. Your IGF-1 changes slowly; monthly testing will show noise, not signal.

Using MyProtocolStack for IGF-1 Tracking

MyProtocolStack lets you upload IGF-1 results alongside your dose logs. The platform visualizes your IGF-1 trend over months and correlates it directly to your injection timeline. You'll see exactly which dose produced which result, eliminating guesswork for future adjustments.

Common Misconceptions

"Higher IGF-1 is always better" - False. Excess GH/IGF-1 increases joint pain, carpal tunnel risk, and potentially metabolic dysfunction. The goal is optimal, not maximal.

"IGF-1 responds immediately to dose changes" - False. Changes take 2-4 weeks to become apparent. Adjusting your dose weekly based on "how you feel" is ineffective.

"IGF-1 is the only marker I need" - False. Monitor prolactin, glucose, lipids, and thyroid function alongside IGF-1 for a complete picture.

This article is for informational and educational purposes only and does not constitute medical advice. Always consult a licensed healthcare provider before starting, adjusting, or stopping any peptide protocol. MyProtocolStack is a protocol tracking and blood work analysis platform - it is not a medical device and does not provide clinical recommendations.