BioTE Hair Rescue: Repair works by combining two potent peptide combinations.. GHK-Cu and AN-Thymulin.  In studies, GHK-Cu has been shown to strengthen existing hair by stimulating growth in areas that are lacking thickness.  Zn-Thymulin is a combination of Zinc and a nonapeptide called Thymulin.  Together, Zn-Thymulin has been shown to extend the anagen phase of hair follicles and reduce hair loss associated with a zinc deficiency.