INTRODUCTION
Facial skin ages over time, showing signs such as fine lines and wrinkles, increased visual and tactile roughness, reduction in firmness and radiance of the skin, and an increase in redness and hyperpigmentation.1,2 Collagen breaks down and a decrease in the amount of water held in the epidermis leads to fine lines and wrinkles.3 Additionally, repeated facial expressions made over time cause persistent wrinkles in the same pattern as the expression line that is formed.4
Peptides are a family of ingredients thought to ameliorate aging skin. Peptides are comprised of amino acids and are used in the body to signal between cells and influence the up- and down-regulation of numerous cellular functions. They have been shown to play an important role in cell signaling, collagen synthesis, and inhibition of neurotransmitter release for reduced muscle contraction.5
A multi-ingredient peptide-based treatment serum has been designed to improve the signs of facial aging especially due to expression lines such as crow’s feet and forehead lines. Effective ingredients include gamma aminobutyric acid (GABA) and 7 different peptides including acetyl hexapeptide-8, acetyl octapeptide-3, dipeptide diaminobutyroyl benzylamide diacetate (DDBD), trifluoroacetyl tripeptide-2, and palmitoyl tetrapeptide-7. GABA is the primary inhibitory neurotransmitter naturally occurring in the
central nervous system and has also been associated with skin barrier homeostasis.6,7 Topical application of peptides, especially those with a fatty acid group attached, have been shown to reduce the signs of aging in facial skin including minimizing fine lines and wrinkles and increasing firmness.8-10 There are several different neurotransmitter inhibiting peptides that are commercially available and these peptides work to reduce fine lines and wrinkles associated with facial expressions caused by underlying facial muscles. The most popular neurotransmitter inhibiting peptide is acetyl hexapeptide-8, which works through inhibition of the formation of the SNARE protein complex and thus inhibits acetylcholine release.11 Reduction in the depth of wrinkles with topical application of acetyl hexapeptide-8 was shown in two previous studies.12,13 Acetyl octapeptide-3 is similar to a sequence found in the SNAP-25 protein and regulates neuronal exocytosis to inhibit neurotransmitter release.14 DDBD is a tripeptide-like compound similar to Waglerin-1, a protein found in the venom of the Temple viper, which blocks neuromuscular contraction.15 DDBD inhibits acetylcholine activity at the neuromuscular synapsis and has an enhanced muscle relaxation activity profile.16 Trifluoroacetyl tripeptide-2 has a lifting effect, reducing skin slackness and sagging. It boosts the production of collagen and inhibits matrix metalloproteinases.17 Palmitoyl tetrapeptide-7 restores communication balance in aging skin specifically by inhibiting proinflammatory interleukin-6 and interleukin-8.18
