Long R3 IGF-1 is an 83 amino acid analog of IGF-1 comprising the complete the human IGF-1 sequence with the substitution of an Arg(R) and for the GLU (E) at position 3, hence R3 and 13 amino acid extension peptide at the N terminus. Long R3 IGF-1 is significantly strong the IGF-1. Long IGF-1 R3 has many functions, such as it can increase the protein synthesis, increase the RNA synthesis, promote fat metabolism and sugar transport and so on. Therefore, for the animals, the Long IGF-1 R3 can promote the muscle cell become large, transform the fat into energy, etc. Moreover, the Long IGF-1 R3 using as the additive for cell culture, is the best cytokine for serum-free culture. The Long IGF-1 R3's difference is because of the tertiary amino acid of its human insulin-like growth factor (IGF-1). IGF-1 R3 can not combine with some certain proteins, thus the human body can maintain longer half decay time, which is 200 times stronger than the natural IGF-1's activity. The purity of the product we get achieve above 95%.