Everyone is Talking About: Peptides

Dr Philippa Cranwell Technical Content Creator

Peptides are in the news at the moment….a lot. While most of the coverage has been in relation to development of the blockbuster peptide-based drugs Ozempic and Wegovy, peptides are also having impact through their use as actives within cosmetic science and personal care. The question is, why? 

Peptides are small, low molecular-weight compounds usually containing between 2 and 50 amino acids which are joined by peptide (also called amide) bonds. Proteins are their larger cousins that can contain hundreds of amino acids, and both play significant roles within the body with functions including cell signaling, providing structure and transportation. Within the cosmetics industry, many products that contain peptides have claims that include ‘plumping’, ‘hydration’, ‘repair’ and ‘strengthening’. And actually, there could be something behind this.  

Peptides are small, which means that they can be absorbed through the skin. Peptides are, therefore, often used to target biological processes. Take the stimulation of collagen production in the skin, for example. 

Collagen is known to provide support in the extracellular space of connective tissues, and as we age, the amount of collagen produced in the body reduces and existing collagen breaks down at a faster rate, which leads to sagging and wrinkles; the visual manifestations of aging skin. Inclusion of small peptides into a formulations, such as palmitoyl tripeptide-38 (Matrixyl Synthe'6), can stimulate production of protein components within the extracellular matrix, such as collagen, leading to improved skin characteristics seen by users, Figure 1. Accordingly, when peptides are included in a product, claims are often relating to restoring youthful skin or ‘defying the signs of aging’.

Figure 1: Structure of palmitoyl tripeptide-38 (Matrixyl Synthe'6). CAS: 1101448-24-1

It is interesting to speculate whether the inclusion of peptides in lip care products could also give interesting benefits. The skin on the lips is thinner and more prone to damage by external environmental factors, including UV and temperature. In addition, as lip skin is thinner and contains fewer sebaceous glands than skin elsewhere on our bodies, lips can suffer from chapping due to an increased rate of water loss, especially in winter. Incorporation of peptides into lip care products, such as masks, balms, creams or lipsticks, could mean that collagen formation is stimulated, leading to a smoother and more evenly textured surface. 

Contact us if you interested in working with TRI on your skin care or lip care research.

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Help Shape TRI's Future - TRI Research Forum

TRI Research Forum, will take place on Friday 12th April 2024 (9:00am – 12:40pm ET), and is a chance to discuss possible future directions for TRI.  Registration is free and exclusive to employees of TRI Member Companies. Research Forum will be streamed live, and available on playback.

Research Forum is a meeting where the TRI team give you an exclusive overview of the new research they have been doing and the new capabilities they have been developing.  It is also a chance for you to give us some guidance on the areas of research that will be of most benefit to your business.  It is, as the title suggests, a forum for discussion.  A chance for the TRI the listen to what you need from our work.

The format of the meeting will be quite simple.  We will have a series of short presentations from our technical Directors, giving you exclusive updates on our internal research programme and news about new equipment purchases.  These will be followed by a series of discussions about possible future directions.  We are proud the announce that the discussions on future directions will, on this occasion, be led by two independent, TRI Adjunct Fellows:  Dr Crisan Popescu, a hair and textiles sciences expert (link to website), and Dr Apostolos Pappas, a skin, nutrition and lipids sciences expert (link to website).

Anyone from our member companies is welcome to take part.  No question is too obvious, and no idea is too ridiculous.  Please come along and help us build our future research and testing capabilities.

The Art of Lipstick: How Skin Tone Influences Your Favorite Shades

Article By Dr. Xuzi Kang Postdoctoral Fellow at TRI Princeton

Ever wonder why the same lipstick looks different on you and your friends? It's not just about the color in the tube; it's a game of “mix and match” with your skin tone. Dr. Xuzi Kang from TRI has been exploring this fascinating interaction and learning how human eye perception and lipstick shades interact.

Color theory of lipsticks:

Like the color theory used in painting, lipstick color theory is a blend of art and science that guides the creation and selection of lipstick shades.

• The First Layer - Skin Tone Sets the Stage:

Think of your skin as the canvas and the lipstick as your paint. That first swipe is where the magic begins. Your skin's undertone plays a crucial role here, subtly shifting the lipstick's appearance. A cool undertone might give red lipstick a pinkish hue, while a warm undertone might make it appear more coral.

• More Layers, More Drama:

As you layer up, the lipstick starts to reveal its true colors. But even then, your skin tone is like a subtle filter, influencing our perception. This effect is why lipstick might look slightly more intense on lighter skin.

• The Color Perception Game:

Our eyes are not just viewers; they're interpreters. They perceive color in context, influenced by surrounding shades. This is why the same lipstick can appear to be a different shade against different skin tones. It's all about how the color interacts with the skin's unique palette.

Delta E (ΔE)

Delta E (ΔE) is a metric that quantifies the difference between two colors in a color space. It's a measure of perceptual color difference, essentially representing how much two colors deviate from each other to the human eye. The term 'delta' signifies a difference or change, while 'E' stands for 'Empfindung,' which is German for 'sensation' or 'perception. Delta E values below 1 represent a barely noticeable color difference to the average person when the colors are separate. In commercial reproduction, a Delta E of 3 to 6 is acceptable, though noticeable to print and graphic experts. Delta E is calculated between skin color and applications to show the color differences with different application layers. 

Experimental

Sample lipstick is applied 0.5 (one swipe), 1, 3, and 5 rounds on the inner arm of panelists with Type III and Type VI skin according to the Fitzpatrick skin scale. A portable colorimeter is used to measure the colors of the lipstick application (Figure 1). Delta E is calculated and compared between skin colors and sample applications (Figure 2). We can see that when zoomed in, the skin colors are very different (Delta E is 18.1), but after applying 5 rounds of the lipstick, the colors are almost the same (Delta E is 2), although, from Figure 1, they look very different with different skin color as the background.

Figure 1. The different rounds of swipes of the lipstick application on the arm (left). Testing using a portable colorimeter (right).

Figure 2. Skin color and lipstick application zoomed in and Delta E comparison (left). Delta E of applications on the two skin types (right).

Its significance for claims:

• Complementing Skin Tones: By applying color theory, R&D teams can develop a range of shades designed to complement various skin tones. This is crucial for claims like "flattering for all skin tones" or "universal shades." Understanding the interactions between lipstick colors and skin undertones (cool, warm, or neutral) allows for creating shades that enhance natural beauty.

• Color Accuracy and Consistency: Color theory ensures that the pigment in the lipstick translates accurately from the tube to the lips. This is essential for claims like "true-to-color" applications. It involves studying how different pigments mix and how they appear when applied, ensuring consistency between batches.

• Color Correction Properties: Some lipsticks are formulated with color correction in mind, using principles of color theory to neutralize discolorations or pigmentation in the lips, supporting claims like "color-correcting lipsticks." 

☺ At TRI, we offer lipstick testing that measures the properties of the lipstick stick itself (hardness, stickiness, and melting behavior), lipstick spreadability (pay-off and layering friction), color effects, lipstick transfer and longevity, and lip hydration. For details, refer to our previous blogs: 

1. Beyond the Tube: Unlocking the Fascinating Science Behind Your Lipstick's Performance

2. Beyond the Tube II: Exploration of Lip Hydration and the Impact of Lipsticks on Moisture Retention

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We are pleased to announce that TRI is starting a promotion season for lipstick testing starting now, enjoy a 10% discount for orders placed before June 30th, 2024!

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