Introduction 550 Molecular Biology 550 Absorption and Transport 550 Metabolism and Excretion 550 Molecular Pharmacology 551 Copperceuticals and Skin: The GHK-Cu Tripeptide 552 GHK-Cu Analogs 552 The Importance of the Copper Peptide Complex 554 Skin Penetration Study of GHK-Cu 554 Immunohistological Assessment 555 Controlled Usage Study in Photodamaged Skin 555 Methods 556 Clinical Results 557 Viscoelastic Properties 558 Ultrasound Measurements 559 Digital Images 559 Safety of GHK-Cu Complex 559 Conclusions 561 References 561 INTRODUCTION Copper peptide, a recent addition to the cosmeceutical pantheon, has an extensive scientific background. This chapter focuses on cutaneous implications.