Peptides in Cosmetics: Types, Characteristics, and Application Insights, PART 1

Peptides, comprised of short amino acid chains, serve as the fundamental building blocks of proteins and various organic compounds. Distinguished by their concise length and the absence of folded secondary structures found in proteins, peptides are termed such if their chain encompasses 50 or fewer amino acids; exceeding this count designates them as proteins. Structural disparities further distinguish them.

Proteins are integral to the composition of hair and skin. While some peptides occur naturally in the body, others are synthetically engineered to emulate the function of natural peptides. For example, collagen, consisting of three polypeptide chains, sees an augmentation in production when peptides are introduced, leading to firmer and more youthful skin.

Advantages of Peptides for Skin:

1. 1. Enhanced Skin Barrier: Serving as the body’s shield against bacteria, UV rays, pollutants, and toxins, the skin’s protective barrier can be compromised by factors like excessive exfoliation, pollution, stress, and inadequate sleep. Peptides contribute to fortifying this barrier.

1. 1. Wrinkle Reduction: Collagen, enhancing skin elasticity and density, diminishes the prominence and depth of wrinkles.

1. 1. Improved Skin Elasticity: In addition to collagen, peptides form elastin fibers, contributing significantly to skin elasticity.

1. 1. Inflammation Reduction: Peptides exhibit anti-inflammatory properties, aiding in alleviating inflammation, repairing damaged skin, and promoting an even skin tone. Some peptides possess antimicrobial attributes, neutralizing bacteria causing acne.

Mechanism of Peptide Action on the Skin: Peptides in cosmetic formulations consist of small particles with 6–7 amino acids. Their low molecular weight facilitates easy penetration of the epidermis. The form of the cosmetic product determines their mode of penetration—either directly through epidermal cells or between cells. Their penetration speed and depth hinge on the chemical nature of the amino acid, accentuated by increased stratum corneum hydration, as observed in occlusive dressing effects (e.g., sheet masks). Hydrophilic substances exhibit optimal skin penetration and retention.

Additionally, peptides exhibit water-binding properties, rendering them exceptional moisturizers. This quality is harnessed in formulations designed to enhance hydration, fortify the skin barrier, and smooth wrinkles.

Peptide Varieties: Peptides fall into four categories: signal peptides, carrier peptides, neurotransmitter inhibitor peptides, and enzyme inhibitor peptides.

Neurotransmitter Inhibitors
These peptides are incorporated into cosmetics to address wrinkles by hindering the release of acetylcholine through diverse chemical interactions. This inhibition renders muscles unable to contract, inducing relaxation. Extreme neurotransmitters, such as Curare toxin and botulinum toxin (Botox), have less invasive counterparts developed for topical use, relaxing facial mimic muscles and reducing wrinkle-causing contractions. In vivo studies highlight a notable 30% reduction in certain wrinkles.

Noteworthy Examples:

• • Argireline (Acetyl Hexapeptide-3, Acetyl Hexapeptide-8)

• • SYN-AKE (Dipeptide Diaminobutyroyl Benzylamide Diacetate)

• • Inyline (Acetyl Hexapeptide-30)

• • SNAP-8 (Acetyl Glutamyl Octapeptide-3)

• • Leuphasyl (Pentapeptide-18)