⚠ FOR LABORATORY RESEARCH USE ONLY · NOT FOR HUMAN CONSUMPTION · QUALIFIED RESEARCHERS 21+
// PB-0035 Protein Growth Hormone

IGF-1 LR3

Long R3 IGF-1 analog.

IGF-1 LR3 (Long R3 IGF-1) is a modified recombinant analog of insulin-like growth factor 1 engineered for reduced IGFBP binding and extended half-life. Originally developed for research in cell culture (where IGFBPs in serum interfere with IGF-1 bioavailability). Supplied as research-grade material with 3rd-party HPLC verification and full Certificate of Analysis per lot.

01

Compound profile.

// CHEMICAL & STRUCTURAL SPEC — IGF-1 LR3
MOLECULAR FORMULA
C400H625N111O115S9
Protein · growth hormone class.
MOLECULAR WEIGHT
9,117.0 Da
Monoisotopic / reported mass.
CHAIN LENGTH
83 aa
Primary structure residues.
ORIGIN
Recombinant modified IGF-1
Source or discovery context.
STUDIED PATHWAYS
IGF-1R
Reported in published literature.
REPORTED HALF-LIFE
~20–30 hr
Long vs native IGF-1.
HPLC PURITY
99.8%
Minimum release spec · typical >99.9%.
APPEARANCE
White lyo.
White to off-white lyophilized form.
// PRIMARY STRUCTURE
13-residue N-terminal extension + Arg³ substitution + 70-residue mature IGF-1 sequence

// Long R3 IGF-1 differs from native human IGF-1 in two ways: a 13-residue N-terminal extension (MFPAMPLSSLFVN) and an arginine-for-glutamate substitution at position 3 of the mature chain. These modifications dramatically reduce binding to IGFBP (IGF binding proteins), extending serum half-life and bioavailability.
02

What the literature reports.

IGF-1 LR3 (Long R3 IGF-1) is a modified recombinant analog of insulin-like growth factor 1 engineered for reduced IGFBP binding and extended half-life. Originally developed for research in cell culture (where IGFBPs in serum interfere with IGF-1 bioavailability).

Reported mechanism

IGF-1 LR3 is a full IGF-1 receptor agonist. The LR3 modifications reduce binding to IGF binding proteins 1-6 by approximately 3-fold, increasing free IGF-1 activity roughly 3x compared to native IGF-1. The Arg³ substitution is the major contributor to reduced IGFBP binding.

Research context

Widely used in cell and tissue culture research as an IGF-1R agonist that is not sequestered by serum IGFBPs. Not FDA-approved for any indication. WADA prohibited (S2).

The above summarizes published research literature. This is not medical advice, a protocol, or a recommendation for use. This compound is supplied for laboratory research only.

03

Storage & release.

SHIP TEMP
Ambient
Lyophilized; stable at room temp in transit.
UNOPENED
Refrigerate
Lyophilized, protected from light.
RECONSTITUTED
~28 days
At 2–8°C; never freeze solutions.
RELEASE DOC
COA · per lot
3rd-party analytical · attached at ship.
lab@peptidebros:~$ cat release.igf-1-lr3.IGF-26-Q1-0017.log
// lot release record
compound IGF-1 LR3 (C400H625N111O115S9)
lot.id IGF-26-Q1-0017
class protein
mw.theoretical 9,117.0 Da
mw.observed 9,117.0 Da  [PASS]
purity.hplc 99.91%  [> 99.5% spec]
endotoxin < 0.125 EU/mL  [PASS]
sterility no growth  [PASS]
release.status RELEASED
04

Common questions.

What's the molecular profile?+

IGF-1 LR3 is a protein (83 amino acids, approximately 9,117.0 Da). Formula: C400H625N111O115S9.

The full structural data and release specifications are in the Compound Profile section above. Every lot ships with an independently verified Certificate of Analysis.

How is purity verified?+

Each lot is independently verified by a 3rd-party analytical laboratory (STERIS Labs, Alcami Analytical, or equivalent) before release. Release specification is HPLC purity ≥ 99.5% (typical > 99.8%), mass spectrometry identity match within ±0.5 Da, water content < 5.0% Karl Fischer, and endotoxin < 0.25 EU/mL by LAL (USP <85>).

Look up the full COA for your lot at coa-lookup.html.

How is the compound shipped and stored?+

All compounds ship at ambient temperature in discreet, tamper-evident packaging. Lyophilized peptide powder is stable at room temperature for typical transit windows, which is why research-grade vendors ship this way. Tracked; signature not required.

Store unopened lyophilized product at 2–8°C protected from light. Once reconstituted, most peptides are stable at 2–8°C for approximately 28 days (compound-dependent).

Is this compound FDA-approved?+

Widely used in cell and tissue culture research as an IGF-1R agonist that is not sequestered by serum IGFBPs. Not FDA-approved for any indication. WADA prohibited (S2).

All PeptideBros compounds are sold strictly as chemical reference materials for in-vitro laboratory research. They are not for human consumption.

Every lot,
on paper.

HPLC-verified. Mass-spec confirmed. Ambient-stable transit. The paperwork other vendors hope you never ask for.