IGF-1 LR3 1mg

Description

IGF-1 LR3 exists for a practical reason. Native IGF-1 in serum is almost entirely bound to IGFBP-3 in a complex with the acid-labile subunit, which makes dose-response work in cell culture unpredictable. Two modifications — an N-terminal 13-residue extension and an Arg3-for-Glu3 substitution — cut IGFBP-3 affinity by roughly 600-fold. The research version of IGF-1 you actually want to use is this one.

Proposed Mechanism

Receptor biology is unchanged. LR3 binds the IGF-1 receptor through the same kinase signaling — PI3K/Akt and MAPK cascades — as native IGF-1. The difference is not what the peptide does at the receptor; it is how much of the peptide ever reaches the receptor. With IGFBP affinity suppressed, a larger fraction of each dose stays bioavailable. King et al. (1992) published the characterization of the Arg3 substitution effect that anchors this logic.

Research Literature

King et al. (1992) is the characterization paper for the Arg3 substitution. Francis et al. (1988, Biochemical Journal) published the Long-R3 form with the N-terminal extension for recombinant production. Bagley et al. (1989) is the early functional characterization in muscle cell differentiation assays. The combined modifications produce a compound particularly suited to cell culture work, where endogenous IGFBPs in serum would otherwise sequester native IGF-1 before it reached the receptor.

Further reading: PubMed references for this compound.

Research Applications

Used in cell-culture IGF-1 receptor agonist standard applications, muscle differentiation assays, PI3K/Akt signaling studies, and IGFBP-independent IGF-1R activation research. The 600-fold IGFBP-3 affinity reduction is the peptide’s defining feature.

Supplied strictly for laboratory research use. Not for human or veterinary use.

Reconstitution

Supplied as a lyophilized powder. Reconstitute with bacteriostatic water prior to use. Use the Peptigo reconstitution calculator for guidance on volume and concentration.

Storage

• Unopened: room temperature up to 30 days during transit; refrigerate at 2-8°C long-term.
• Reconstituted: refrigerate at 2-8°C; stable 4-6 weeks. Protect from light.

Quality Verification

Every batch is independently tested by Janoshik Analytical. Certificates of Analysis include HPLC-UV purity, LC-MS identity confirmation, LAL bacterial endotoxin quantification, and USP <71> sterility testing.

Not a drug, supplement, or cosmetic. For in vitro research use only. Not for human consumption.

Frequently Asked Questions

Is this product legal to purchase in Canada for research use?

Peptigo supplies all products strictly for laboratory and in vitro research use. The compound is not a drug, supplement, or cosmetic, and is not sold for human or veterinary use. Researchers purchasing for their own laboratory work, university research programs, or independent in vitro protocols are the intended customer base. Health Canada’s April 2026 advisory specifically addresses unauthorized injectable peptide use; the research-use framing of this product is independent of that consumer-use category.

How is purity verified, and where can I see the Certificate of Analysis?

Every batch is tested independently by Janoshik Analytical, an accredited third-party laboratory. The standard testing panel includes HPLC-UV purity verification, LC-MS identity confirmation, LAL bacterial endotoxin quantification, and USP sterility testing. The Certificate of Analysis for each batch is available on the product page after purchase, and the testing methodology is detailed on the Lab Testing reference page.

What is the standard reconstitution and storage protocol for laboratory use?

The compound is supplied as a lyophilized powder. The standard diluent for reconstitution in research protocols is bacteriostatic water (0.9% benzyl alcohol). The Peptigo reconstitution calculator handles the volume-and-concentration arithmetic for a given target research dose. Unopened lyophilized peptide is stable at room temperature for up to 30 days during transit and should be refrigerated at 2-8°C for long-term storage. Reconstituted peptide should be refrigerated at 2-8°C and is typically functional for 4-6 weeks; protect from light.