Cosmetics

This category contains Endogenic line signal peptides studied in skin models. The focus is on collagen and elastin synthesis, extracellular matrix remodelling, and fibroblast and keratinocyte signalling. The name “cosmetics” points to the research direction: skin biology. The descriptions stick to Research Use Only principles and discuss the mechanism studied in a model, not an effect on the complexion.

All of these compounds act on skin cell signalling and matrix remodelling, from stimulating structural protein synthesis to modulating transmission at the neuromuscular junction. Each family, however, works through a different molecular mechanism.

Alongside the skin signal peptides, the category includes three compounds with a different profile: Epithalon, a tetrapeptide studied in models of cellular ageing; Melanotan 2, an α-MSH analogue that also acts beyond the skin; and Minoxidil – not a peptide, but a small molecule that opens potassium channels.

Compound families in this category

Copper peptides: GHK-Cu

GHK-Cu, the tripeptide glycyl-histidyl-lysine bound to a copper ion, is one of the best-described skin signal peptides. In fibroblast models it is studied in extracellular matrix remodelling, collagen synthesis and metalloproteinase modulation. A smaller pack of GHK-Cu is also available.

Palmitoyl matrikines: Matrixyl-type complexes

These are matrix signal peptides conjugated to a palmitic acid residue, intended to increase their affinity for the skin in research models. Matrixyl 3000 combines a palmitoyl tripeptide and a palmitoyl tetrapeptide. They are studied in fibroblast cultures, in work on stimulating the synthesis of extracellular matrix components: collagen, fibronectin and hyaluronic acid.

Acetyl peptides: SNAP-8

SNAP-8 is an octapeptide (acetyl octapeptide-3), a fragment of the SNAP-25 protein. It is studied in models of the SNARE complex and of neurotransmitter release modulation at the neuromuscular junction. This is a mechanistic line of research, at the level of cell signalling.

Pineal peptides: Epithalon

Epithalon (epitalon, AEDG) is a synthetic tetrapeptide with the sequence Ala-Glu-Asp-Gly, developed as a simplified analogue of epithalamin, a pineal gland extract studied in Russian gerontology. It is studied in models of cellular ageing: telomerase activity, telomere length and gene expression in cell cultures. A large share of the publications on it come from a single research group, which needs to be taken into account when assessing the data. In this category you will find Epithalon in a pen and the Epithalon + GHK-Cu kit. The state of the research and its limitations are discussed in the article Epitalon and telomeres.

Melanocortins: Melanotan 2

Melanotan 2 (melanotan II, MT-2) is a synthetic cyclic analogue of α-melanotropin (α-MSH) that acts as a non-selective melanocortin receptor agonist. Stimulating the MC1R receptor on melanocytes shifts pigment synthesis towards eumelanin, and this pathway – melanogenesis in melanocyte cultures – is studied in skin biology models. MC3R and MC4R receptors in the central nervous system account for some of its systemic effects, so the compound cannot be described purely as a skin peptide. In this category you will find Melanotan 2 PEN, Melanotan 2 lyophilisate 10mg and MT-2 spray. The mechanism and risk profile are described in the article Melanotan II – the melanocortin mechanism and risk profile.

A small molecule outside the peptide group: Minoxidil

Minoxidil is not a peptide. It is a pyrimidine derivative that opens ATP-sensitive potassium channels, and the active substance of authorised medicines: a topical one for androgenetic alopecia and an oral one for hypertension. In hair follicle research, its action is linked to potassium channel opening and vascular effects, not to the androgen axis; the full mechanism has not been explained. In this category you will find the Minoxidil 50mg Endogenic solution and Minoxidil MAX capsules. The differences between minoxidil, medicines that inhibit DHT formation and RU58841 are discussed in the article on androgenetic alopecia, DHT and RU58841.

Bases and carriers for research formulations

Topical application models and penetration studies use cream bases and carrier solutions in which the peptides are dispersed. You will find a wider selection of peptides in the Peptides category.

Regulatory status
The peptides in this category have no marketing authorisation as medicines, and in this range they are not offered as ingredients of consumer products. GHK-Cu, Matrixyl-type complexes and SNAP-8 remain Research Use Only materials for skin biology research. They are not on the WADA Prohibited List (local, non-systemic action), but that does not change their status as reagents.

Regulatory status: Epithalon, Melanotan 2 and Minoxidil
Epithalon and Melanotan 2 have no marketing authorisation as medicines in any country. The WADA Prohibited List does not name them, but as non-approved substances they fall under class S0 and are prohibited in sport at all times. The only α-MSH analogue authorised for marketing is afamelanotide, approved for a narrow medical indication – a different molecule from Melanotan 2. The dermatological literature describes cases of melanoma in people using melanotan (Paurobally et al., 2011), as well as changes in existing moles. Minoxidil is the active substance of authorised medicines and is not on the WADA Prohibited List. In the EU it may not be used as a cosmetic ingredient: Regulation (EC) No 1223/2009 lists it in Annex II among prohibited substances. In this category, all three compounds are Research Use Only reagents.