Peptides may be small in size, but they are remarkably influential players in our biology. So, what is a peptide and are the benefits really all they are made out to be? Present in all cells and tissues, peptides perform a wide range of essential functions in our bodies, and they are notably one of the most powerful molecules at regulating and altering our biological processes.

This makes peptides a key gadget in scientists’ tool boxes for developing effective and innovative products across various industries, such as the biomedical, cosmetic, and even agricultural markets. In particular, peptides have made waves in the cosmetic, beauty, and skincare industries for their ability to penetrate the skin’s multiple layers when applied topically. While most ingredients in topical skin care products stay on the surface of the skin, peptides are able to penetrate through the skin barrier and reach skin’s deepest layers due to their small size. This lends to a few remarkable benefits of peptides. Here are the top 3:

• Peptides can strengthen the skin barrier (epidermal function).
• Peptides can enhance skin elasticity and firmness.
• Peptides can fight inflammation.

Peptides don’t actually do this themselves; they delegate!
Peptides of different sizes and sequences have different functionalities. Some act as hormones, communicating information through the blood from one tissue to another. Others act as carrier proteins, ushering essential molecules from point A to point B. And others, called signaling peptides, trigger the synthesis of their larger counterpart, proteins.
Peptides used in skincare are usually signaling peptides, triggering the synthesis of structural proteins in skin such as collagen: an anti-aging MVP.Collagen is a critical structural protein of the skin. It forms fibrous networks which replenish dead skin cells and promotes skin strength, elasticity and firmness. Collagen also strengthens the skin barrier, which acts like the bouncer at the front door to keep out the toxic molecules, pathogens, and external aggressors. It also locks essential molecules in, such as water, keeping the skin hydrated.
Unfortunately, collagen production reliably declines with age. According to a 2021 study, Skin collagen through the life stages: importance for skin health and beauty states, “from early adulthood, fibroblasts become less active and collagen production declines by about 1.0%-1.5% a year.” ²There are two plausible ways to introduce collagen supplementation to the body to try to make up for its steady decline with age: ingestion of hydrolyzed collagen and topical application of collagen-stimulating ingredients.
A 2019 study, A Collagen Supplement Improves Skin Hydration, Elasticity, Roughness, and Density: Results of a Randomized, Placebo-Controlled, Blind Study, recorded the impacts of collagen on 72 healthy women aged 35 years or older. It determined that ingesting hydrolyzed collagen significantly improved skin hydration, elasticity, roughness and density. ³
Unfortunately, ingested collagen must travel through the digestive tract, where proteins are broken down into their building blocks, called amino acids, and redistributed all over the body. The amino acids that do get sent to the skin are often not recognized as collagen fragments and serve as building blocks for general protein synthesis. Thus, to maximize collagen levels in support of healthy skin, scientists recommend stimulating natural collagen production directly in the epidermis. Thus, applying topical ingredients, such as in the form of a peptide moisturizer, that promotes collagen production locally is a perfect way to ensure that collagen is building in the skin specifically.⁴When considering how to use peptides in skin care, it should be noted that some topical collagen-stimulating ingredients have negative side effects. While ingredients such as retinol can be applied topically to promote collagen production, it does this at the expense of the skin's barrier function. Alternatively, ingredients like peptides are easily absorbed by the skin cells and promote collagen production without breaking down the skin barrier. When comparing peptides vs retinol, this is easily the most significant factor that distinguishes the two ingredients. As we age, our body becomes increasingly populated with free radicals which are, quite literally, unstable. These reactive molecules damage DNA, RNA and proteins, causing inflammation, which is one of the main causes of skin aging. Antioxidants tackle these reactive free radicals by neutralizing them before they can break anything. ⁵
Both peptides and proteins are capable of antioxidant activity, but peptides are recorded to be superior antioxidants since small molecules are more easily absorbed into tissues.⁶Interestingly, topical application of peptides have such a remarkable effect on skin due to their penetration and biological capabilities, that they are actually being studied clinically to fight chronic inflammation at the molecular level.
A 2020 study highlights the potential of topical application of Antimicrobial Peptides (AMPs) to fight inflammation in individuals with Atopic Dermatitis (AD), a common chronic inflammatory skin disease. They conclude, “AMPs not only represent potent antimicrobial agents but are also efficacious at restoring the TJ barrier, reducing itching symptoms, and suppressing Th2 inflammation, and, thus, they may become a new option for barrier repair therapy in AD treatment.” ⁷Nothing and no one is perfect, including our pal the peptide. There are several benefits of peptides for skin, but also challenges.

• Peptides are fairly new. There is a lot of promise, and supporting research on peptides' biological abilities and applications across various industries. However, most papers call for further investigation. Within cosmetic formulations, alternatives like hyaluronic acid have been around for longer, and are more researched.
• Peptides are pricey. Peptides often have long, inefficient and expensive manufacturing processes. Additionally, modifications to improve peptide’s properties, such as skin penetration, adds to the manufacturing cost.
• Not all peptides are equal! Peptides of different length and sequences have different functionalities. Controlled studies clearly demonstrate that some peptides have superior rejuvenating effects, while others have no effect whatsoever. You want to make sure you don’t end up with a dud! ⁸

While peptides show much promise, be wary of the fact that the word “peptide” has, in many ways, become a marketing tactic. So, before using a peptide-based product, make sure you do your due diligence and ensure its effects on the skin and its skin penetration capabilities have been scientifically tested and validated. Remember, a peptide’s effects are only useful if it’s reaching the deepest layers of the skin.Some of the most commonly used peptides in the anti-aging skincare industry are Palmitoyl Tetrapeptide-7, Palmitoyl Oligopeptide and Acetyl Hexapeptide-8. A 2020 study, Trending Anti-Aging Peptides, compared the efficacy of the three and found that all demonstrated anti-aging effects, and are valid ingredients for anti-aging supplements. ⁹
Palmitoyl Tetrapeptide-7 and Palmitoyl Oligopeptide are relatively new ingredients with no reported issues of sensitivity, toxicity or hormone imbalance. However, Palmitoyl Tetrapeptide-7, specifically, has research indicating that overuse of this peptide may lead to skin tone discoloration. ¹⁰
Acetyl Hexapeptide-8 is significantly more researched but not recommended for sensitive skin. Try to avoid formulations that have alcohols, as the combination can dry the skin and make wrinkles more apparent. ¹¹After five years of research and development, OneSkin developed the first peptide scientifically proven to reduce the skin’s biological age by preventing the onset of cell senescence. This proprietary peptide is decapeptide-52, also known as the OS-01 peptide, which powers OneSkin’s line of OS-01 Topical Supplements. ¹²
The OS-01 peptide has undergone rigorous testing, including extensive penetration studies, which has validated its ability to penetrate through the dermal layer of skin. The OS-01 peptide has also been scientifically proven to promote skin’s natural production of collagen, elastin, and hyaluronic acid, increase skin’s epidermal thickness, and subsequently improve skin’s barrier function.
The OS-01 peptide’s penetration capabilities coupled with its positive effect on skin’s function, is what makes it the most advanced topical peptide in the skin care industry to improve skin health at the molecular level.

• Peptides are used in cosmetics for their unique ability to penetrate the skin and work on the cellular level.
• Signaling peptides are able to naturally stimulate collagen production within the skin, strengthening the skin barrier, and enhancing skin elasticity and firmness.
• Peptides have superior antioxidant properties to proteins due to their higher rate of absorption and are even being researched to fight chronic inflammatory conditions.
• Not all peptides are created equal. Depending on the size and mechanism of action of a peptide, certain peptides have superior rejuvenation properties than others.
• OneSkin’s proprietary peptide, OS-01, is a scientifically validated, high penetrable peptide which has been scientifically proven to improve skin health markers at the molecular level, making OneSkin’s Topical Supplements one of the most cutting-edge topical products on the market.

By Kiran Kumar: Kiran is studying Biotechnology Engineering at UC San Diego. She is highly enthusiastic about longevity sciences, specifically reproductive aging! You can find more on her at thisiskirank.com.

1. https://nakedpoppy.com/blog/the-skin-barrier-why-its-the-secret-to-really-good-skin/#:~:text=What%20Is%20a%20Damaged%20Skin,the%20skin%2C%E2%80%9D%20says%20Plescia
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