IGF-1 DES

Most IGF-1 in the body is held by IGF-binding proteins, which limit how much reaches the IGF-1 receptor. The glutamate at position 3 matters for that binding, so removing the first three residues makes the molecule bind these proteins much less^1,3. More of it stays free to activate the IGF-1 receptor, a signal that promotes cell growth, protein building and glucose uptake.

In cell culture it is about ten times more potent than full-length IGF-1¹. In pigs and marmoset monkeys it left the bloodstream faster than IGF-1 yet lowered blood glucose more strongly and for longer, which the authors linked to its weak binding-protein attachment⁴.

The evidence comes from cells and animals. In cultured chick cells, a binding protein blunted IGF-1 and IGF-2 but not the truncated form, explaining its higher potency³. In rats with reduced kidney function, a week of infusion improved weight gain and nitrogen balance and appeared to slow muscle protein breakdown⁵. The Australian group that characterized it reported especially marked growth effects on gut tissue in animals¹.

In pigs and marmosets it lowered blood glucose two to three times more potently than IGF-1⁴. That group noted in 1996 that clinical uses had not been evaluated¹, and ClinicalTrials.gov lists no trials. It is prohibited in sport, and anti-doping chemists found oxidized, lower-quality peptide forms in black-market products⁶. A 2026 review groups IGF-1 analogs among compounds used without regulatory approval and with uncertain composition².

Not approved by the FDA or any other regulator for any use⁶. The approved IGF-1 medicine, mecasermin (Increlex), is the full-length molecule, not this variant.

No published clinical studies describe its side effects in people. In animals it lowered blood sugar more strongly and for longer than IGF-1, suggesting low blood sugar as a likely risk⁴. A 2026 review of unregulated peptides acting on the growth hormone-IGF-1 axis, a group that includes IGF-1 analogs, lists fluid retention, joint and muscle pain, blood-sugar disturbances and injection-site reactions, plus a plausible but unproven concern about promoting abnormal cell growth². Black-market samples analyzed by anti-doping chemists contained oxidized, lower-quality forms⁶.

1. Ballard et al., Int J Biochem Cell Biol 1996PubMed
2. Dominikowski et al., Front Endocrinol 2026PubMed
3. Ross et al., Biochem J 1989PubMed
4. Tomas et al., J Endocrinol 1997PubMed
5. Martin et al., Am J Physiol 1991PubMed
6. Mongongu et al., Drug Test Anal 2021PubMed