Tomas and colleagues published a series of CSIRO studies in the early 1990s showing LR3-IGF-I is approximately 2.5-fold more potent than native IGF-I in rat anabolism — increased body weight, organ growth, and feed efficiency under both freely-fed and food-restricted conditions. The potency advantage comes from poor IGFBP binding, leading to higher free IGF-I activity.
0 human studies · 12 animal studies
LR3-IGF-I is ~2.5-fold more potent than native IGF-I in rat anabolism (Tomas 1992).
Half-life extended to 20-30 hours via reduced IGFBP affinity.
Anabolic in dexamethasone-catabolic rats (preserves muscle mass under steroid stress).
Reduces plasma IGF-1 in continuous infusion via negative feedback.
Top citations
Tomas 1992 — Rat anabolic in dex catabolism
Tomas 1996 — Injection PK/efficacy
Tomas 1993 — Normal female rat anabolic effects
Our take
The animal data is consistent and well-powered. Translation to humans rests on the recombinant IGF-1 (mecasermin) literature, which is a different molecule.