Des(1-3)IGF-1 (des-IGF-1; truncated IGF-1) is a naturally occurring truncated form of IGF-1 found in brain tissue and colostrum, lacking the first three N-terminal amino acids (Gly-Pro-Glu) of the full-length molecule, which significantly reduces its affinity for IGF-binding proteins while largely preserving IGF-1 receptor binding affinity and activating potency. The reduced IGFBP binding of des-IGF-1 is proposed to result in greater bioavailability in CNS tissue where IGFBP-2 normally limits IGF-1 activity; it has been studied as an endogenous component of human cerebrospinal fluid and colostrum, where it may play a role in neural development and neonatal gut maturation. No published human clinical trials, pharmacokinetic studies, or controlled safety evaluations of exogenous des-IGF-1 administration exist in PubMed-indexed journals; available indexed literature is limited to in vitro receptor binding studies, animal models of neurological conditions, and anti-doping detection assays used to identify its presence as a prohibited substance in athletic drug testing. Des(1-3)IGF-1 has no FDA approval or approved indication in any jurisdiction; it is a research compound with no clinical evidence base, classified as a prohibited substance in sport by WADA, and its use as an administered compound carries entirely uncharacterized risks given the absence of any published human data.