IGF 1 LR3 Dosage Guide Muscle Growth Fat Loss Benefits PEP DOSE Gut derived IL 13 contributes to growth via promoting hepatic IGF 1 production Microbiome Springer Nature Link ORF Genetics ISOkine IGF 1 LR3 Growth Factor Full article: Challenges of insulin like growth factor 1 testing Peptide Calculator Accurate Peptide Dosing Made Simple Table 1 from Serum concentrations of insulin like growth factor (IGF) 1 and IGF binding protein 3 (IGFBP 3), IGF 1 IGFBP 3 ratio, and markers of bone turnover: reference values for French children and adolescents and z score comparability