IGF-1 (Long R3, receptor-grade)
A broadly marketed analytical/receptor-grade recombinant IGF-1 preparation (distinct from the approved mecasermin product) used in research settings and diverted for physique use. Human safety and efficacy for the marketed use are essentially uncharacterised.
01 Overview
This entry covers non-pharmaceutical recombinant human IGF-1 preparations sold in the research-chemical and grey markets, as opposed to the FDA-approved therapeutic mecasermin (Increlex). They contain the same IGF-1 receptor agonist but without pharmaceutical quality control, dosing validation, or approved indication.
Because these products are unregulated, their purity and potency vary, and there are no controlled human data supporting the physique/performance uses for which they are diverted. The pharmacology mirrors IGF-1: potent anabolic and hypoglycaemic activity through the IGF-1 receptor.
02 Mechanism
Activates the IGF-1 receptor, driving cellular growth, protein synthesis and insulin-like glucose uptake.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Anecdotal (unvalidated) | 20–50 mcg/day | SubQ | Self-reported diverted use; not a validated or approved regimen. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Anabolic signallingDrives protein synthesis and tissue growth as expected for IGF-1. | IGF-1 receptor-mediated | Preclinical | |
| Glucose uptakeIncreases cellular glucose uptake, the basis for hypoglycaemia risk. | insulin-like | Preclinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| HypoglycaemiaIGF-1's insulin-like activity can cause dangerous low blood sugar. | Severe | Common | Preclinical | |
| Uncertain purity/contaminationGrey-market products may be impure or misdosed, risking reactions. | Moderate | Unknown | Unconfirmed |