Introduction to Peptides

Peptides, also known as “胜肽” in Chinese, are small molecules derived from the degradation of collagen proteins and contain Amino Acid groups. They are naturally occurring components in the human body, forming chain structures of amino acids. Proteins, which we are familiar with, are essentially long chains of peptides. Peptides are formed by linking amino acids through peptide bonds, and each peptide can be composed of various amino acids. Peptides made up of two amino acids are called dipeptides, those with three are tripeptides, and so on. Commonly heard terms like tripeptides, pentapeptides, and even nonapeptides belong to the category of oligopeptides, each with different effects. Peptides with fewer than 10 amino acids are called oligopeptides, those with more are called polypeptides, and those with more than 50 are referred to as proteins. Due to the variety of amino acids they contain, dipeptides and tripeptides also come in different types, leading to the various functions and names of peptides we see today.

Peptides are involved in various bodily functions, including hormones, nerves, cell growth, and reproduction. Their importance lies in regulating the physiological functions of different systems and cells in the body, activating relevant enzyme systems, promoting the permeability of intermediate metabolic membranes, or producing specific physiological effects by controlling DNA transcription or influencing the synthesis of specific proteins.

II. Cosmetic Benefits of Peptides

The biological activity of peptides depends on their amino acid composition and sequence. Almost all physiological processes in the human body are regulated by specific sequences of amino acids forming peptides or proteins. Therefore, bioactive peptides have become a new direction and approach in cosmetic research and application, with increasingly segmented functions such as anti-aging, repair, antioxidant, anti-edema, promoting hair regeneration, inhibiting melanin production, breast enhancement, and weight loss. The skin is the body’s natural barrier against external environmental damage, providing some protection against external stimuli thanks to the dense stratum corneum. However, this also prevents the nutrients in cosmetics from penetrating the skin surface. Nutrients need to pass through the cell membranes of the stratum corneum to enter the dermis, and only a small amount of large molecules and fat-soluble substances can be absorbed through pores and sweat glands. Therefore, most of the cosmetics we use remain on the skin surface, while bioactive cosmetic peptides can more easily penetrate the gaps in the stratum corneum to reach the dermis and exert their effects. Peptides were initially used directly in products by some European and American cosmeceuticals. Their mechanism of action is similar to that of proteins, promoting the proliferation of collagen, elastic fibers, and hyaluronic acid, increasing skin hydration, thickness, and reducing fine lines. Due to the different types of amino acids they contain, they can perform various functions to meet the different needs of the skin.

III. Functions of Various Peptides

1. Dipeptides: Anti-wrinkle (Dipeptide Diaminobutyroyl Benzylamide Diacetate) - Locally blocks nerve transmission of muscle contraction signals, affecting skin nerve conduction, relaxing facial muscles, and smoothing dynamic lines, static lines, and fine lines.
2. Tripeptides: Regeneration (Aldeline) - Tripeptides were the first peptide combinations discovered and are considered growth factors that can stimulate the production of glucosamine and collagen. They were isolated from wound healing tissues in 1990 and have the effect of promoting wound healing and proliferation.
3. Tetrapeptides: Anti-edema (Palmitoyl Tetrapeptide-3) - Reduces edema, improves microcirculation, and enhances blood circulation.
4. Pentapeptides: Firming (Palmitoyl Pentapeptide-3, also known as Matrixyl) - Initially used in dermatology to promote collagen proliferation and achieve skin firming, often combined with other moisturizing ingredients to accelerate tightening and lifting effects.
5. Oligopeptides: Elasticity (Palmitoyl Oligopeptide) - Promotes the proliferation of collagen and hyaluronic acid, increasing skin hydration and elasticity.
6. Hexapeptides: Anti-wrinkle (Acetyl Hexapeptide-3, also known as Argireline) - Also known as a botulinum toxin-like peptide, it inhibits the excessive release of neurotransmitters, affecting the transmission of proteins between subcutaneous nerves and muscles, effectively reducing dynamic wrinkles such as crow’s feet and nasolabial folds. French dermatologists have found it particularly effective for wrinkles around the eyes.
7. Nonapeptides: Whitening (Nonapeptide) - When the skin is stimulated by external factors or UV radiation, α-melanocyte-stimulating hormone in the basal layer cells binds to receptors on melanocytes, directly stimulating melanocytes and activating tyrosinase to start secreting melanin. Nonapeptides can block the transmission of α-melanocyte-stimulating hormone signals at the source, preventing it from binding to receptors on melanocytes and reducing melanin production.
8. Copper Peptides: Revitalizing (Copper Peptide, GHK-Cu) - Copper peptides are a perfect combination of divalent copper ions and tripeptides. Initially used as an oral medication for treating gastric ulcers, copper is an essential element in the body and aids in wound healing in skin tissues. Copper ions cannot enter the skin alone, but through the linkage of glycine, lysine, and histidine with a copper ion, copper peptides can be introduced into the skin, effectively promoting collagen and elastin production and antioxidant capabilities, deeply penetrating the skin to enhance self-repair and smooth wrinkles. Copper peptides are non-irritating and suitable for sensitive skin.