You have probably already seen the word “peptides” on a serum, cream, or anti-aging treatment. Found in many Korean skincare formulas, peptides are often associated with firmness, collagen, and reducing visible signs of aging. But behind this term lies a large family of ingredients, with very different mechanisms and properties.
So, what are peptides in skincare really? What do they do? Are they actually effective against wrinkles? And most importantly, how do you know which ones to choose for your skin?
Peptides are short chains of amino acids. Amino acids are the small building blocks that help form proteins such as collagen and elastin, two proteins that are essential for maintaining the skin’s structure and firmness. Some peptides used in cosmetics can act as messengers: they provide skin cells with signals that can influence mechanisms related to collagen, skin repair, and skin aging.
But not all peptides do the same thing. That is precisely what makes them interesting… and sometimes difficult to understand.
What are peptides in skincare?
A peptide is made up of several amino acids linked together. Amino acids are small molecules that help build proteins in our bodies. Depending on their composition, peptides can have different roles in the skin.
Some peptides are naturally present in the skin and are involved in different biological functions. In cosmetics, peptides can also be manufactured and added to skincare formulas to reproduce or support specific actions that benefit the skin.
One of the particularities of cosmetic peptides is that they can act as messengers. Some peptides are studied for their ability to stimulate skin cells involved in the production of collagen and other components that contribute to the skin’s structure.
To understand this mechanism, it is worth taking a moment to look at the extracellular matrix. This refers to the network of elements surrounding skin cells that helps support and maintain the skin’s structure. It contains collagen, elastin, and other substances that contribute to the skin’s firmness and overall quality. Some peptides can influence mechanisms involved in maintaining or renewing this structure.
This is why there is no single type of “peptide” in skincare, but rather a wide range of peptides with different properties.
And this is an important point to keep in mind: seeing the word “peptide” on a product does not, by itself, tell you what that product can actually do for your skin.
What are the benefits of peptides in skincare?
Peptides are primarily studied for their potential in skincare products designed to address visible signs of aging. Their use is particularly associated with supporting mechanisms linked to collagen, improving the appearance of wrinkles, and helping the skin maintain a firmer, more resilient appearance.
Their benefits do not stop there. Depending on the peptide used, some formulas may also target hydration, the skin barrier, or certain inflammatory processes.
A 2024 review of cosmetic peptides describes four main categories based on their mechanism of action: signal peptides, carrier peptides, neurotransmitter-inhibiting peptides, and enzyme-inhibiting peptides.
The anti-aging benefits of peptides in skincare
Peptides are probably best known for their potential anti-aging benefits.
As we age, collagen production and the skin’s ability to maintain its firmness gradually decline. The skin slowly loses density and elasticity, wrinkles become more visible, and its structure changes.
Some peptides are studied for their ability to stimulate mechanisms associated with collagen production. Others may act on mechanisms involved in the formation of expression lines or help preserve the proteins that contribute to the skin’s structure.
The results are gradual: peptides will not make a wrinkle disappear after a few applications. Their benefits are better seen with consistent use over several weeks, helping to gradually improve the appearance of the skin.
A controlled clinical trial on Palmitoyl Pentapeptide-4, for example, observed an improvement in the appearance of wrinkles and fine lines after 12 weeks of use.
Other peptides are studied for different mechanisms. Acetyl Hexapeptide-3, for example, has been evaluated in a clinical trial targeting crow’s feet, with improvements observed in some participants after eight weeks.
The different types of peptides in skincare
There is a wide variety of peptides used in skincare products. To understand this family of ingredients, it is more useful to classify them according to their function than to simply memorize a list of names.
Signal peptides
Signal peptides are probably the best known in anti-aging skincare. They work by sending signals that can stimulate certain mechanisms involved in the production of components of the extracellular matrix, including collagen.
They are particularly studied for their ability to stimulate the activity of fibroblasts, skin cells involved in the production of collagen, elastin, and other components essential to the skin’s structure.
Carrier peptides
Carrier peptides have a different function. They can bind to certain elements and help transport them within the skin.
Copper peptides, also known as copper peptides, belong to this category. One of the best-known examples is GHK-Cu, a complex made up of a peptide called GHK combined with copper. This peptide is studied for its role in several mechanisms involved in maintaining the skin, including collagen production and mechanisms associated with skin repair.
Neurotransmitter-inhibiting peptides
Some peptides are studied for their ability to reduce signals involved in muscle contraction. Acetyl Hexapeptide-3, often known as Argireline, is one of the best-known examples.
The aim is particularly to target expression lines. However, their action should not be compared to that of a medical treatment or injection: cosmetics containing these peptides work at a very different level.
Enzyme-inhibiting peptides
Enzyme-inhibiting peptides work by limiting the activity of certain enzymes found in the skin. Some of these enzymes can contribute to the breakdown of proteins such as collagen and elastin.
The goal of these peptides is therefore to help preserve the components that contribute to the skin’s structure and firmness for longer.
What peptides to look for in skincare products?
There is no universally “best” peptide. The right choice depends primarily on what you are looking for in your routine and on the formula as a whole.
For a routine focused on firmness and visible signs of aging, you may come across signal peptides such as Palmitoyl Tripeptide-1, Palmitoyl Tetrapeptide-7, or Palmitoyl Pentapeptide-4. The latter is one of the peptides that has been clinically studied for its effects on the appearance of wrinkles and fine lines.
For formulas containing copper peptides, look for ingredients such as GHK-Cu or Copper Tripeptide-1 on the INCI list. GHK-Cu has been particularly studied for its properties related to maintaining and supporting skin repair.
For targeting expression lines, Acetyl Hexapeptide-8 is one of the best-known peptides. Clinical studies have evaluated its potential effects on the appearance of crow’s feet.
But a list of peptides in skincare should not become a race to count ingredients. A serum containing ten peptides is not necessarily more effective than a formula containing one well-studied peptide that has been properly formulated.
The quality of the formula, the choice of peptide, its stability, and its concentration also play an important role. Current research continues to explore ways to optimize peptide stability and delivery within the skin in order to make the most of their potential.
When to use peptides in a skincare routine?
Peptides can generally be used both morning and evening.
How to layer peptides with other skincare ingredients?
Peptides can easily be incorporated into a routine containing other active ingredients and can be combined with many ingredients commonly used in skincare.
As always, it is best to follow the manufacturer’s recommendations when a specific formula advises against certain combinations, particularly with some copper peptides.
Are peptides really necessary in a skincare routine?
Peptides are not essential to every skincare routine, but they can be particularly interesting for people looking to address early signs of aging, loss of firmness, fine lines, or loss of skin density.
They can therefore be a valuable addition to a routine when these concerns become a priority, alongside essentials such as hydration and sun protection.
Can you be allergic to peptides in skincare?
Cosmetic peptides are generally well tolerated, but as with any cosmetic ingredient, a skin reaction is still possible. It may be caused by the peptide itself or by another ingredient in the formula. Safety assessments, including those conducted on Acetyl Hexapeptide-8, have found it to be safe under the cosmetic conditions evaluated.
If you have particularly reactive skin or a history of allergies to cosmetics, it is therefore best to introduce a new product gradually and stop using it if you experience an unusual reaction.
Are peptides in skincare safe during pregnancy?
Cosmetic peptides are not among the main categories of skincare ingredients that are discouraged during pregnancy. Dermatological recommendations particularly focus on retinoids, which should be avoided during this period.
As safety always depends on the complete formula, however, check the product’s ingredients and speak to your doctor or midwife if you have any concerns.
Are peptides in skincare safe for kids?
Peptides are primarily used in skincare products intended for adults, particularly to target signs of aging. They are therefore not necessary in a child’s skincare routine.
For younger skin, a simple routine suited to their age is preferable. If a child has a specific skin concern, it is better to seek advice from a healthcare professional rather than introducing an anti-aging peptide serum or treatment.
Should you add peptides to your skincare routine?
Peptides are among the most interesting active ingredients in modern skincare, particularly when it comes to addressing visible signs of skin aging.
Their appeal lies largely in their diversity: some are associated with collagen production, others with copper delivery or mechanisms involved in expression lines. They therefore do not all work in the same way.
Peptides are not a miracle ingredient, but when carefully chosen and used consistently as part of an appropriate routine, they can become a valuable ally for taking care of your skin over the long term.
Discover our peptide-infused skincare products and find the formula best suited to your skin’s needs with our selection of Korean skincare at Shifumie.
