On-Cycle Blood Work Monitoring

What gets measured during use

No label or trial sets an on-cycle schedule for research peptides. A clinician orders these labs, and the blood work schedule overview has the background.

On-Cycle Testing Schedule

What trials measured, and when

Timing	Tests	Purpose
Every 6 months	IGF-1, glucose, cortisol	MK-677 trial
Week 26	IGF-1, HbA1c	Tesamorelin label
As needed	Glucose	Increlex label

Users report rechecks at 6-12 weeks, an interval no study has tested.

Key Markers for Monitoring

Marker	Concern Threshold
IGF-1	Persistently above 3 SDS (label)
Fasting glucose	100 mg/dL or higher (ADA prediabetes)
HbA1c	5.7% or higher (ADA prediabetes)

GH Secretagogue Specific

Priority Markers

Marker	Rationale	Trial finding
IGF-1	GH pathway activity	Young-adult levels on MK-677 25 mg/day
Fasting glucose	Insulin sensitivity	Up about 5 mg/dL
Fasting insulin	Resistance	Insulin sensitivity fell

The trial enrolled adults aged 60-81. Users mostly report testing IGF-1 and glucose markers.

Secondary Markers

Marker	Concern	Response
Prolactin	Some users add it	Not in the trial or label
Liver enzymes	Not studied	User panels; baseline comparison

IGF-1 Peptide Specific

IGF-1 LR3's evidence level is preliminary; it has no human trial data. The label for mecasermin (Increlex), a prescription IGF-1, calls for pre-meal glucose checks at the start, and 42% of trial participants had hypoglycemia. Users mostly describe watching for low-blood-sugar symptoms.

Healing Peptide Monitoring

BPC-157/TB-500

No human trial offers monitoring guidance for either. BPC-157's evidence level is emerging (a 2-person IV pilot found no biomarker changes). TB-500's is preliminary, and FDA reports no human exposure data for it. Many users skip routine labs.

Interpreting Results

A clinician interprets these results; the tables report sources, not actions.

Response Matrix

Finding	Meaning	Action
IGF-1 persistently above 3 SDS	Over-response	Tesamorelin label: stopping may be considered
Glucose rising	Insulin sensitivity	Seen with MK-677
No IGF-1 change	Possible quality issue	A lab can't show what was in the vial

Red Flags

Finding	Concern Level	Source
Glucose 126 mg/dL or higher	Diabetes range	ADA, confirmed on retest
HbA1c 6.5% or higher	Diabetes range	Tesamorelin: 5% vs 1% placebo by week 26
Low blood sugar symptoms	Label warning	Increlex label reports seizures

What we still don't know

The tesamorelin label says long-term effects of high IGF-1 are unknown, and no study has tested on-cycle testing intervals. Comparison points sit in baseline testing and the post-cycle assessment.