Tetrapeptide-21

A four amino acid (Glycine – Glutamic acid – Lysine – Glycine) peptide that belongs to the group of signal peptides that mimic skin-protein breakdown products to trick the skin into creating some nice new skin proteins, such as collagen (if this sentence is not clear, here is a bit longer and nicer explanation). 

According to its manufacturer, Tetrapeptide-21 shows superior collagen, hyaluronic acid and fibronectin (all nice and important skin elements) boosting activity, and can smooth and minimize all kinds of wrinkles. The in-vitro data (made on human dermal fibroblast culture) showed that compared to Matrixyl (the first-generation Matrixyl peptide called Palmitoyl Pentapeptide-4), the collagen production in the presence of Tetrapeptide-21 was almost 2-fold higher (and about 2.5-fold vs the control). This data was confirmed by an in-vivo study that compared on 60 volunteers 0.5% Tego Pep 4-17 (10ppm of Tetrapeptide-21), 5% Tego Pep 4-17 (100ppm of Tetrapeptide-21) and 10% Matrixyl (10ppm of Palmitoyl Pentapeptide-4) and found that Tetrapeptide-21 performed better after 8 weeks for skin volume, roughness and elasticity. 

The manufacturer also did another 60 people anti-wrinkle study with 4% Tego Pep 4-17 (compared to vehicle) where they have some nice before and after pictures showing visible-to-the-naked-eye wrinkle reduction around the eye area.