Research Only Research & Experimental

IGF-1 DES(1-3)

also known as: DES(1-3) IGF-1, DES IGF-1, des1-3 IGF-1

Deleting the first three amino acids of IGF-1 cripples IGFBP binding while preserving receptor activity — giving DES(1-3) roughly 10× the in vitro potency of native IGF-1 at promoting cell growth in IGFBP-rich environments.

A naturally occurring IGF-1 variant (first identified in bovine colostrum and human brain tissue) lacking the Gly-Pro-Glu N-terminal tripeptide, which binds IGF-1R normally but has dramatically reduced affinity for the IGF-binding proteins that normally sequester IGF-1 in circulation.

Mechanism of action

Binds IGF-1R with similar affinity to native IGF-1 but with ~10-fold reduced binding to IGFBP-3, the dominant serum IGFBP. In IGFBP-rich environments — which is essentially all extracellular human biology — DES(1-3) is therefore substantially more bioavailable at the receptor. Downstream signaling (PI3K/Akt/mTOR and MAPK) is identical to native IGF-1.

Primary uses

  • Research reagent for IGF-1 bioavailability studies
  • Cell culture growth media
  • Community bodybuilding use (unapproved, no safety data)

Typical dosing

research-only varies (subcutaneous (community))

No human clinical dosing standard. Community use carries the same hypoglycemia and theoretical cancer-promotion concerns as LR3, with even less pharmacokinetic data to guide dosing.

Regulatory status

Not approved. Research reagent only. Unlike LR3, DES(1-3) occurs endogenously in small quantities and was not deliberately engineered.

References

  1. [pubmed] Ballard FJ, et al. "Des(1-3)IGF-I: a truncated form of insulin-like growth factor-I." Int J Biochem Cell Biol, 1996;28:1085-1087.
  2. [pubmed] Francis GL, et al. "Insulin-like growth factor (IGF)-I and IGF-II which partially lack N-terminal amino acids have reduced affinity for IGF-binding proteins." J Mol Endocrinol, 1992;8:213-223.

Related peptides

IGF-1 LR3

A 13-amino-acid N-terminal extension plus Arg3 substitution gives IGF-1 LR3 roughly 2–3× the potency of native IGF-1 in bioassays — a research-reagent favorite that became a bodybuilding staple despite no human approval.

PEG-MGF

A pegylated fragment of a proposed muscle-specific IGF-1 splice variant — the underlying "MGF" biology remains scientifically contested, and PEG-MGF itself has no human clinical data.

MGF

The native, non-pegylated splice variant of IGF-1 produced by skeletal muscle in response to mechanical overload — extremely short-lived in vivo and therefore superseded by PEG-MGF in research-chemical markets.

Somatropin (HGH)

FDA-approved recombinant human growth hormone — the direct hormone replacement, with multiple clinical indications, prescription-only status, and specific federal criminal provisions against off-label distribution.
Disclaimer

This entry is for educational purposes only and does not constitute medical advice. Dosing information reflects published regulatory or research data and is not a recommendation. Many compounds described here are not approved for human use in the United States. Consult a licensed medical professional before considering any peptide therapy.