Ceramides: What are ceramides, and what do they do?
What are ceramides?
Ceramides are a type of fatty acid known as lipids. They are found naturally within skin cells and comprise approximately 50% of the skin’s outer layer (the epidermis) [1]. The basic structure of ceramides consists of a sphingoid base (an 18-carbon chain with a 4,5-trans double bond, 2-3 hydroxyl groups, and a terminal amine group) linked to a fatty acid chain (ranging from 12-26+ carbon molecules) via an amide bond [2]. The length of the fatty acid chain and the addition of various chemical groups determines the identity and function of specific ceramide molecules [2]. As such, ceramides constitute a complex, heterogeneous class of lipids which play diverse roles in cellular processes [3]. However, in the context of skincare, ceramides are typically used for their role in protecting skin barrier integrity.
Function of ceramides
As discussed, ceramides are a highly complex class of lipids with diverse functions. When it comes to skincare, however, ceramides are notable for their role in maintaining skin barrier health. Ceramides play several physiological roles in the regulation of skin barrier function [4]. They play a central role in the formation of the epidermal barrier, which protects against environmental factors and prevents trans-epidermal water loss, both of which can lead to dry and damaged skin [5]. They also regulate signalling pathways involved in key cellular processes, including skin cell differentiation and apoptosis [6]. This helps maintain healthy skin cell turnover and promotes overall skin health.
Benefits of ceramides for skin
Ceramides are generally beneficial for skin health due to their roles in regulating skin cell turnover, promoting barrier integrity, and protecting against epidermal dehydration. Moreover, evidence suggests that ceramides can improve disturbed skin conditions, such as atopic dermatitis (eczema) and psoriasis, which have been associated with diminished ceramide levels [7].
How do ceramides work in skincare products?
In skincare products, ceramides work by reinforcing your skin’s barrier function, which helps prevent moisture loss and protect against environmental insults. Structurally, ceramides act like “grout” between “tile-like” epidermal cells, which creates a tight seal and helps hold in hydration [6]. Studies have suggested that applying ceramide-containing cream to the skin can reduce dryness, especially in people with dehydrated and/or eczema-prone skin [6].
Peptides: What are peptides, and what do they do?
What are peptides?
Peptides are short chains of amino acids which form the building blocks of various proteins within the skin [8]. The identity and function of a given peptide is ultimately determined by which amino acids make up the peptide chain and how they are linked together. Considering that there are 20 basic amino acids which can be linked in various combinations and configurations, the number of possible peptides is large [8]. Hence, like ceramides, peptides are a diverse and heterogeneous group of molecules. Also similar to ceramides, peptides are produced by the body and can be found naturally within the skin. However, many skincare products incorporate additional peptides in their formulations to give the skin an extra boost of these crucial molecules [9].
Function of peptides
Peptides function in diverse biological processes, often serving as signaling or regulatory molecules in physiological processes such as immune defense, stress responses, growth, homeostasis, and reproduction [8]. Regarding their functions in skin health, peptides may help reduce inflammation, even out skin tone, and reduce the appearance of wrinkles [8]. Additionally, peptides can stimulate your skin to make collagen [8], which serves as a key structural molecule in the dermis and helps promote firmer skin. As we age, collagen production tends to decrease, which can cause the skin to appear more wrinkled [9]. Peptides may help counteract this process by boosting endogenous collagen production.
Benefits of peptides for skin
Studies suggest that peptides may reduce premature skin aging by boosting collagen; improve the skin’s barrier integrity; moisturize the skin; protect the skin from UV damage; and promote anti-inflammatory processes which dampen acne and irritation [8]. Peptides may also help generate elastin and collagen proteins deep within skin tissues, which play important roles in tissue structure and flexibility [8]. This may help reduce the appearance of fine lines and wrinkles, and promote firmer and smoother skin.
How do peptides work in skincare products?
Because peptides are small molecules, they can penetrate the outer surface in order to access deeper layers of the skin [10]. Within the epidermis and dermis of the skin, peptides can act as cellular messengers, relaying signals which boost collagen and elastin production [8]. Additionally, certain peptides stimulate fibroblast activity and act as modulators of the extracellular matrix, thereby regulating the skin’s microstructure [8].
Ceramides vs peptides: A comparison
Clearly, both ceramides and peptides play important roles in maintaining skin health. However, the two classes of molecules are distinct in their structure, function, and most effective applications.
Differences in structure and function
Ceramides are lipids, made up of long-chain fatty acids that link with other molecules to promote cellular function. They are the major constituent of the stratum corneum, the outermost layer of the skin, and play an essential role in structuring and maintaining the water permeability barrier of the skin [11].
Peptides are short chains of amino acids that make up certain proteins needed by the skin. They can penetrate more deeply into the skin and regulate various cellular processes, such as collagen synthesis and extracellular matrix modelling [8]. For this reason, they play important roles in maintaining the structural integrity and elasticity of skin tissue.
Moisturizing
Are ceramides or peptides better for moisturizing?
When it comes to moisturizing, ceramides are generally considered better for hydration because they lock in moisture and prevent dryness and irritation due to trans-epidermal water loss [12]. Peptides, on the other hand, mainly function in skin structure and repair.
Preventing oily skin
Are ceramides or peptides better for oily skin?
For oily skin, peptides may be a better choice because they can help reduce inflammation without adding extra oil to the skin. However, ceramides are not contraindicated for those with oily skin, and some sources suggest that ceramides may benefit those with oily skin by balancing the skin’s lipid composition [13].
Anti-aging
Are ceramides or peptides better for anti-aging?
Both ceramides and peptides can have anti-aging effects, though they elicit these effects for different reasons. Ceramides can minimize the appearance of wrinkles and help brighten the skin by trapping moisture, whereas peptides can stimulate collagen and elastin production, promoting firmer, younger-looking skin [14].
Can ceramides and peptides be used together?
In most cases, ceramides and peptides can be used together. Given their unique structures and functions, the two molecules can complement each other and help create a comprehensive skincare regimen that targets diverse elements of skin health. However, if you are planning to test out a new combination of ceramide- and peptide-based products, it is worth performing a patch test first by applying a small amount of the two products to a limited area of your skin and monitoring for any irritation or other reactions.
Conclusion
Ceramides and peptides are two classes of molecules that play important roles in maintaining healthy skin. Ceramides are lipid-based molecules with an important role in promoting a healthy skin barrier, retaining hydration within the skin, and alleviating dryness. Peptides are short chains of amino acids that can serve as signalling molecules or subunits for larger proteins within the skin. Peptides can penetrate more deeply into the skin due to their small molecular size. In the deeper layers of the skin, peptides can serve as signalling molecules that regulate cellular processes including collagen synthesis, elastin production, anti-inflammatory pathways, and cellular turnover. Overall, both classes of molecules play important roles in skin health, and incorporating ceramides and peptides into your skincare routine may help address concerns such as dryness, irritation, dullness, wrinkles, and acne.