human 134 Humans 111 Article 107 controlled study 77 Peptides 74 metabolism 70 male 66 female 60 peptide 57 Animals 50 chemistry 49 nonhuman 47 adult 46 animal 46 Male 42 Female 41 genetics 41 unclassified drug 36 major clinical study 32 middle aged 30 mouse 30 Mice 24 Middle Aged 23 Peptide Fragments 21 peptide fragment 21 aged 20 pathology 20 procedures 20 signal peptide 20 Adult 19