What is a Peptide?
In Chinese, peptides are commonly referred to as 肽 (tai). They serve as the fundamental units that constitute proteins. Similar to proteins, peptides are sequences of two or more amino acids interconnected by peptide bonds, also known as amide bonds. While peptides are smaller in comparison to proteins, their aggregation forms the fundamental structure of proteins.
Peptides in Skincare
In the realm of skincare, peptides function as powerhouses that stimulate cells to increase collagen production, which is the predominant protein in the skin. Consequently, peptides have become sought-after components in anti-ageing products designed to boost collagen synthesis, showcasing their efficacy in combating fine lines and wrinkles.
Currently, there is a wide variety of bioactive peptides available as cosmetic ingredients. They can be categorized according to their mechanism of action:
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Signal Peptides: Stimulate collagen/elastin synthesis and cell proliferation.
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Carrier Peptides: Deliver trace elements for wound healing and improve skin elasticity.
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Neurotransmitter-inhibitor Peptides: Provide moisturizing effects and inhibit melanin synthesis.
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Enzyme Inhibitor Peptides: Reduce the breakdown of collagen/elastin proteins.
Bioactive Mechanisms
Bioactive peptides are renowned for their potent single or multifunctional biological attributes, such as antimicrobial, antioxidant, anti-ageing, and anti-inflammatory capabilities. They play a crucial role in enhancing skin well-being through various mechanisms, encompassing:
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Extracellular matrix synthesis
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Innate immunity
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Inflammation modulation
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Pigmentation regulation
Part 1: Signal Peptides
Exploring bioactive peptides for cosmetic applications has unveiled novel possibilities in skincare and beauty. In this section, we take a closer look at the first major category: Signal Peptides.
The “Messengers” of the Skin
Signal peptides, also known as collagen-stimulating peptides, act as messengers regulating the skin’s protein turnover. They possess the capacity to resemble the transmitted signal during Extracellular Matrix (ECM) protein synthesis.
These peptides are responsible for stimulating the production of ECM proteins in skin fibroblasts. This results in increased biological responses such as the production of:
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Collagen
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Elastin
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Fibronectin
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Glycosaminoglycan
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Proteoglycan
This process increases fibroblast activity, leading to higher production of collagen and elastin. Furthermore, signal peptides can reduce the degradation of existing skin collagen and act as growth factors to activate protein kinase C (e.g., Hexapeptide-12), which is responsible for cell growth and migration.
Why Do We Need Them?
Signal peptides are promising ingredients for addressing skin aging. Fibroblasts undergo senescence (aging), resulting in diminished proliferation and a decline in collagen synthesis, especially of Type 1 collagen. Meanwhile, existing collagen faces further deterioration due to proteolytic enzymes. Signal peptides aim to replenish collagen levels associated with this fibroblast senescence.
Top Signal Peptides in the Market
Diverse signal peptides are available for topical application. Below is a summary of selected top peptides currently used in formulations:
| Name of Peptide |
Commercial Name |
Mechanism of Action | Cosmetic Functionality |
| Palmitoyl Tripeptide-1 | Matrixyl 3000™, Biopeptide-CL | Sub-fragment of the carboxyl terminal pro-peptide of type I collagen. Enhances ECM production in fibroblasts, effectively stimulating collagen (I, II, and III) and fibronectin production. | Anti-ageing, Anti-wrinkle, Firming agent, Increase ECM synthesis |
| Palmitoyl Tripeptide-5 | SYN®-COLL | Mimics thrombospondin 1 tripeptide sequence. Activates TGF-β to increase Type I and III collagen. Reduces collagen breakdown by interfering with MMP-1 and MMP-3 degradation. | Anti-wrinkle, Firming agent, Improves stretch marks, Reduces pigmentation |
| Palmitoyl Tetrapeptide-7 | Biopeptide-EL | Fragment of immunoglobulin G. Reduces interleukin-6 (IL-6) secreted by keratinocytes, inhibiting the inflammatory process. | Improve skin elasticity, firmness, and softness; Reduce skin irritation |
| Nicotiana benthamiana Hexapeptide-40 | Epitensive™ (Lipotrue) | Plant-epidermal growth factor (EGF). Stimulates the synthesis of collagen, elastin, and fibronectin; stimulates proliferation of keratinocytes and fibroblasts. | Anti-wrinkle, Anti-sagging |
Case Study: SYN®-COLL
SYN®-COLL serves as an excellent example of an innovative anti-wrinkle approach. It comprises two synergistic activities:
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Boosting collagen production: It mimics the human body’s own mechanism to produce collagen via TGF-β (Tissue Growth Factor). It binds to a particular sequence in the Thrombospondin I (TSP) molecule to activate latent TGF-β, which then stimulates collagen synthesis in human fibroblasts.
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Collagen protection: It protects collagen from degradation by inhibiting the expression of matrix metalloproteinases (MMP 1 and 3) and proinflammatory cytokines.
Figure: SYN®-COLL mechanism and efficacy tests showing collagen boosting and wrinkle reduction
In vivo studies with 60 healthy volunteers applied twice daily for 84 days showed strong effects on all types of age-related wrinkles, proving it to be a safe and painless alternative to collagen injections.
Conclusion: The Future of Ageless Skin
Signal peptides have proven to be a cornerstone in modern anti-ageing formulations, offering a targeted approach to skin rejuvenation by essentially “telling” our cells to rebuild what time has diminished. As we continue to decode the biological language of the skin, these bioactive ingredients stand out for their ability to deliver visible results—improving firmness, reducing wrinkles, and restoring a youthful complexion without invasive measures.
This is just the beginning of our deep dive into the incredible world of peptides. Stay tuned for the next installment of this series, where we will explore Carrier Peptides and how they deliver essential trace elements to further enhance skin health and elasticity.
Written By: Dr. Tan Kian Meng, PhD in Engineering Technology (UTHM)
REFERENCES
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