Department of Bioorganic Chemistry, Chair of Organic Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Krakow, Poland Institute of Quality Sciences and Product Management, Cracow University of Economics, Rakowicka 27, 31-510 Krakow, Poland; [EMAIL_ADDRESS]  
plays a key role in cell growth and migration [3]. Signal peptides are used either to enhance metabolism of fibroblasts or fasten hair growth.  
Carnosine (\(\beta\)-(_Ala-His_)) is a dipeptide which is also used as a food supplement. Its wound healing activity is a feature making it a cosmetic, especially for eye cream, because _stratum corneum_ around the eyes is the thinnest [8]. It has been bound with palmitic acid into palmitoyl-carnosine in order to enhance permeation through _stratum corneum_ so that the compound can be effectively used on the whole face (Figure 1).  
Palmitoyl tripeptide-3 (Syn-Coll, (_Pal-Lys-Val-Lys_) bistrifluoracetate) stimulates synthesis of collagen, also through TGF-\(\beta\)[9].  
A palmitoylated peptide is Pal-KTKS (Matrixyl, palmitoyl pentapeptide)--Lys-ThrThr-Lys-Ser. KTKS is a procollagen 1 fragment and it stimulates synthesis of collagen, elastin and hyaluronic acid [10]. Another peptide, also patented by Sederma, Pal-GQPR (palmitoyl 7-tetrapeptide, Matrixyl 3000)--Gly-Glu-Pro-Arg, stimulates collagen synthesis by fibroblasts. Moreover, it inhibits production of interleukin IL-6 resulting in anti-inflammatory effect. \(Pal-KMO_{2}K\) under the tradename MATRIXYL Synthe-6 (\(MO_{2}\) corresponding to a dioxygenated methionine) [9].  
VGVAPG constitutes a fragment of elastin (elastin-derived peptides EDPs) and is a chemotactic signal peptide for fibroblasts. EDPs initiate human mesenchymal stem cells (hMSCs) differentiation into more tissue-specific cells [11]. It also decreases in the level of reactive oxygen species (ROS) [12].  
Certain peptides have been developed for stimulation of hair growth. For example, tripeptide-1 combined with biotin (vitamin H)--biotinyl GHK in Lash Accelerator--or a preparation preventing hair loss Procayil. The longest of this group is KGF (Keratin Growth Factor) used in EyeLash Enhancer, containing 164 amino acids.  
Leuphasyl--pentapeptide-18 (_Tyr--D-Ala-Gly-Phe-Leu_) inhibits secretion of sebum. A response for androgenic hair loss may be acetyl-tetrapeptide-3 [13]. It also decreases neuronal excitation by imitating activity of enkefalins [14].  
The tradename Renokin, includes decapeptide-10, oligopeptide-54 (CG-Nokkin), decapeptide-18, acetyl decapeptide-3, and oligopeptide-42 which promote hair growth [15].  
There are also peptides preventing hair greying: \(\alpha\)-melanocyte stimulating hormone (acetylhexapeptide-1, _Ac-Nle-Ala-His-D-Phe-Arg-Trp-NH_) [16; 17] Melitane)-\(\alpha\)-MSH biomimetic peptide. On the other hand, PTP-20 (Palmitoyl tetrapeptide-20, Greyverse) was developed for the use of MC1 receptor agonist and it increases quantity of melanin in human melanocyte culture [18].  
Aquashine PTX 4 contains decapeptide-29, oligopeptide-62, acetyl decapeptide-3, oligopeptide-24, oligopeptide-72, oligopeptide-34, oligopeptide-51 with sodium hyaluronate [19]--the peptide ingredients of the preparation have been patented for all possible uses in the skin. _Ac-Asp-Val-Lys-Tyr-OH_ increases the expression of fibulin-5, increases synthesis of type I collagen as well as elastin through overexpression of various genes [20].