Baseline Testing Before Peptide Use

What Gets Measured Before Starting

Baseline labs give later results a reference point. A clinician orders and interprets them. This page covers what trials and labels measured and what users report; the blood work schedule overview has more detail.

The 2-year MK-677 trial in adults aged 60 to 81 measured IGF-1 and insulin sensitivity at baseline and every 6 months. The Egrifta WR (tesamorelin) label asks prescribers to evaluate glucose status before starting. The Wegovy label sets no baseline blood panel. Research-use peptides have no label.

Core Baseline Panel

Hormone Panel

Test	Purpose	Adult Male Range (Varies by Lab)
IGF-1	GH pathway baseline	Age-specific; varies by lab
GH (random)	Pulsatile	One reading says little
Total Testosterone	Hormonal status	300-1000 ng/dL
Free Testosterone	Bioavailable T	Assay-specific
Estradiol	Balance assessment	10-40 pg/mL
Prolactin	Baseline	2-18 ng/mL
TSH	Thyroid function	0.4-4.0 mIU/L

Metabolic Panel

Test	Purpose	Commonly Cited Threshold
Fasting glucose	Insulin sensitivity	100-125 prediabetes; 126+ mg/dL diabetes (ADA)
HbA1c	Long-term glucose	5.7-6.4% prediabetes; 6.5%+ diabetes (ADA)
Fasting insulin	Sensitivity	Often >10 µIU/mL; no agreed cut-off
HOMA-IR calculation	Resistance assessment	Often >2.5

Growth hormone opposes insulin; in the MK-677 trial, fasting glucose rose 5 mg/dL on average.

Lipid Panel

Test	Purpose	Common Target
Total cholesterol	Cardiovascular	<200 mg/dL
LDL-C	Atherogenic risk	<100 mg/dL
HDL-C	Protective factor	>40 mg/dL
Triglycerides	Metabolic health	<150 mg/dL

Organ Function

Test	Purpose	Typical Range
AST	Liver function	10-40 U/L
ALT	Liver function	7-56 U/L
Creatinine	Kidney function	0.7-1.3 mg/dL
eGFR	Kidney function	>60 mL/min

Other Tests Users Report

Test	Reported Reason
CBC with differential	Overall health
CRP or hs-CRP	Inflammation baseline
Vitamin D	General panel
PSA (over 40)	Prostate baseline

Preparation and Records

Fasting matters for glucose and lipids, not IGF-1 (MedlinePlus).

Factor	What Labs and Users Describe
Fasting	8+ hours for glucose (ADA); users often report 10-12
Timing	Morning
Exercise	Users often skip training the day before

Users also report using the same lab each time. Later testing is covered in on-cycle monitoring and the post-cycle assessment.

What we still don't know

No trial has defined a baseline panel for research-use peptides, or whether baseline values predict safety.