What Are Peptides In Skincare?

I have heard so much about peptides. I remember being gifted a face mask that contained peptides, the face mask had this marketing claim “to boost collagen” “anti-aging”, a very visually appealing face mask. When I decided to put it on my face, I had the feeling that it was working but was it? I wasn’t sure.

But I am glad to be able to write to you about peptides, I have heard so much about their anti-aging benefits but with my research, there was more to peptides than just anti-aging.

Peptides are present in our bodies, they perform various biological functions. For example, they play a key role in regulating blood sugar levels through insulin and help manage blood pressure with peptides like angiotensin and bradykinin. Peptides also contribute to lactation and childbirth, where oxytocin helps initiate labor and milk production and so much more. They are also present in the skin, where they play a critical role in maintaining its health, structure, and resilience.

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Our skin’s structure is largely made up of collagen, a protein made up of long chains of amino acids. Think of collagen as the scaffolding that gives your skin its firmness and thickness. Unfortunately, as we age, collagen breaks down, leading to fine lines, wrinkles, and an overall thinning of the skin.

When collagen breaks down, it releases amino acids. Amino acids on their own can’t perform any biological activities hence they combine together to form peptides. Peptides will then signal to the skin to produce new collagen and help repair damage. Peptides, in essence, are like little messengers that boost the skin’s ability to rebuild and restore itself.

But the real question remains—if you apply topical peptides to your skin, do they really work? And what exactly are peptides in skincare?

What Are Peptides In Skincare?

Peptides result from the linking of two or more amino acids. For example, when the peptide is made of two amino acids, such as tyrosine and arginine (Tyr‐Arg), it is called a dipeptide. Three amino acid is called tri-peptide, four amino acid combinations is a tetrapeptide.

So most times, peptides are also referred to as polypeptides. In skincare, both terms are used interchangeably. Any peptide with more than 100 amino acids is called a protein, hence collagen, elastin are called proteins.

Peptides are building blocks for proteins like collagen and elastin, which are crucial for maintaining the skin’s structure and firmness. When applied topically, these peptides send signals to your skin, prompting it to produce more collagen and repair itself. This process can result in smoother, firmer, and more youthful-looking skin.

Do Topical Peptides Actually Work?

Research shows that they can, but with a few considerations. While peptides may not be a quick fix, consistent use can help reduce the appearance of fine lines, improve skin texture, and boost hydration. Clinical studies have indicated that some peptides, such as palmitoyl pentapeptide-4 (also known as Matrixyl), have been effective in reducing wrinkles and enhancing skin elasticity.

However, as with many skincare ingredients, their efficacy can depend on the formulation, delivery system, and concentration in the product. Peptides tend to work best in combination with other active ingredients like antioxidants, hyaluronic acid, and vitamins.

Curious to know which peptides you should look for and how they can benefit your skin? Keep reading to know the different types of peptides and how they work in skincare!

How Does Peptides Work In Skincare?

Remember that collagen decreases with age and during the breakdown process, it produces certain peptides. These peptides signal your skin that it’s losing collagen, pushing it to make more. So when you apply peptides topically, they trick your skin into thinking collagen is breaking down, encouraging it to produce fresh collagen. In other words, signal peptides trick fibroblasts to generate more collagen, helping reduce wrinkles and restore a youthful appearance. This is smart!

Carrier peptides, on the other hand, deliver copper to enzymes that are key in collagen and elastin production, as well as wound healing and reducing free radical formation. Lastly, peptides that block nerve signals can smooth out lines caused by muscle movement, acting like a topical version of Botox.

Types of Peptides in Skincare

Peptides in skincare are categorized based on their specific functions. The most common types include:

1. Signal Peptides: These peptides send signals to the skin to produce more collagen, elastin, and other structural proteins. Examples include palmitoyl pentapeptide-4 and palmitoyl tripeptide-5, which are often found in many anti-aging creams.
2. Carrier Peptides: Carrier peptides deliver essential trace elements, such as copper or manganese, to the skin, which are necessary for wound healing and collagen synthesis. Copper tripeptide (Cu-GHK) is a well-known carrier peptide used in skincare.
3. Neurotransmitter-Inhibitor Peptides: These peptides work by blocking the release of neurotransmitters that cause muscle contraction, which in turn helps reduce the appearance of wrinkles. Acetyl hexapeptide-3 (Argireline®) is a popular example, often used as a non-invasive alternative to Botox.
4. Enzyme-Inhibitory Peptides: These peptides inhibit enzymes that break down collagen and other proteins in the skin. For example, soy peptides can inhibit the activity of matrix metalloproteinases (MMPs), enzymes that degrade collagen and contribute to skin aging​.

Benefits of Peptides in Skincare

Peptides offer a wide range of benefits for the skin, making them a versatile and valuable addition to skincare routines:

1. Antioxidant

Glutathione (GSH)

Glutathione is one of the most well-known antioxidant peptides. It’s a tripeptide made up of three amino acids: glutamic acid, cysteine, and glycine. What makes it special? It contains cysteine, which gives it strong antioxidant properties, helping to fight free radicals that can damage your skin cells over time. As we age, the levels of glutathione decreases, which may contribute to visible signs of aging, such as wrinkles and dull skin.

Glutathione is also recognized for its potential skin-brightening properties. Some studies, like those by Villarama and Maibach, suggest that it may help reduce pigmentation, leading to a more even skin tone.

Carnosine

Carnosine is another powerhouse peptide with antioxidant properties. It protects skin cells by neutralizing reactive oxygen species (ROS)—those harmful molecules formed when your skin is exposed to oxidative stress, like sun damage or pollution. But carnosine doesn’t stop there; it also combats glycation, a process where sugars attach to proteins, causing them to become stiff and dysfunctional. Glycation can lead to the formation of advanced glycation end products (AGEs), which speed up skin aging by making collagen and elastin less effective.

Carnosine is also linked to wound healing. So, carnosine works double duty, fighting oxidative damage and helping your skin recover.

2. Anti-Aging

One of the most popular claims in skincare is that peptide help to repair and restore the skin’s extracellular matrix (ECM) for anti-aging purposes. The ECM is essential for maintaining skin structure and firmness, and as we age, its gradual breakdown leads to wrinkles and other signs of photoaging.

Matrikines for example, are naturally occurring fragments of the ECM that possess tissue-repairing properties. Think of them as signals that tell your skin to regenerate and repair itself. One of the most popular matrikine peptides is Palmitoyl-KTTKS. This powerful pentapeptide, derived from a fragment of pro-collagen I, stimulates the production of not only collagen I but also collagen IV, fibronectin, and glycosaminoglycans. These are key components that help plump the skin, improve skin elasticity, and smooth fine lines and wrinkles.

In clinical studies, creams containing Pal-KTTKS have been shown to significantly improve skin thickness and firmness, leading to a visible reduction in fine lines and wrinkles. The peptide works by encouraging the production of collagen and other ECM proteins, making it a go-to ingredient for anti-aging formulas.

3. Strengthens Your Skin Barrier

Peptides are not only known for their anti-aging properties but also for their role in supporting the skin’s barrier function. One example is Acetyl Heptapeptide-4, a peptide developed to protect the skin from the damaging effects of pollution and stress by promoting a healthy balance of skin’s natural microbes, or microbiota. A balanced microbiome is essential for strengthening the skin’s defense mechanisms and maintaining proper hydration levels.

In clinical studies, Acetyl Heptapeptide-4 has shown promising results in reducing transepidermal water loss (TEWL), a key indicator of barrier strength. This means that it helps skin retain moisture even after being exposed to damaging factors like surfactants, which can strip the skin of its natural oils.

4. Boost Hair Growth

One peptide that has shown promise in this area is GHK, which is known for its wound-healing properties. When paired with biotin, a vitamin important for hair and nail health, GHK becomes even more effective. In clinical tests, this biotinyl-GHK peptide was shown to significantly boost hair growth.

Clinical trials involving patients with alopecia (hair loss) also reported improvements in the anagen-to-telogen ratio, meaning more hair follicles were in the growing phase (anagen) compared to the resting phase (telogen), resulting in less hair fall and improved hair density.

Limitations of Peptides in Skincare

While peptides offer many benefits, there are some limitations to consider:

1. Skin Penetration

The outer layer of your skin, known as the stratum corneum (SC), is not the main target for peptides. For peptides to deliver their benefits—like boosting collagen, reducing wrinkles, or improving elasticity—they need to reach the living layers of the skin. This includes the epidermis (where keratinocytes and melanocytes live), the dermis (where fibroblasts produce collagen), and even deeper layers like the hypodermis.

However, getting peptides through the skin barrier is easier said than done. Peptides, even small ones, are hydrophilic (water-loving) and often have an electrical charge that makes it difficult for them to penetrate deeply into the skin. For example, carnosine, a well-known dipeptide, struggles to get past the first or second layer of the stratum corneum on its own.

So, how do we help peptides penetrate the skin?

Researchers have found that by attaching a lipophilic chain (a fatty acid) to peptides, we can increase their ability to cross the skin barrier. One study showed that adding a fatty acid to carnosine boosted its penetration by over 100 times. Impressive, right? But here’s the catch, this method works best for smaller peptides. As peptides get longer (more than six or seven amino acids), their ability to penetrate the skin decreases significantly.

Recent research is exploring new ways to improve peptide delivery. Cell-penetrating peptides (CPPs), which are amphiphilic (able to interact with both water and fats), are showing promise. Additionally, attaching certain chains like poly-arginine or using hyaluronic acid (HA) conjugates may enhance penetration.

Another technique being investigated is the use of liposomes—tiny, fat-based carriers that can encapsulate peptides and help them move deeper into the skin. However, more research is needed to fully understand how effective these formulations are.

2. Stability

Yes, peptides can be fragile, especially in aqueous (water-based) environments where they may undergo hydrolysis—a process where water breaks down the peptide structure. But the good news is that with the right formulation, this challenge can be managed.

Skincare chemists have found that using stabilizers and excipients (ingredients that help protect active ingredients) can significantly improve the stability of peptides in cosmetic products. So it is essential that when buying peptides, buy from manufacturers that know what they are doing.

3. Potential for Allergies

When it comes to peptide safety in skincare, the general rule is: the smaller the peptide, the less likely it is to cause any issues. Unlike larger proteins, peptides are usually too small to trigger allergic reactions, which makes them a great option for most skin types.

However, not all peptides are created equal. Some peptide sequences could potentially cause unwanted side effects, but this is rare. To minimize the risk, most skincare products use biomimetic peptides—these are peptides designed to closely mimic the ones naturally found in your skin. Because they are almost identical to human peptides, the likelihood of toxicity is extremely low.

4. They are Expensive

Peptides used in skincare are expensive to produce, especially when they have a defined sequence and high purity (over 90%). While extracting peptides from natural sources like protein hydrolysates is possible, it’s even more costly. This is why most peptides in cosmetic products are synthetic, created through a step-by-step process by combining individual amino acids. This can make them less accessible for some consumers.

Final Thoughts

Peptides have emerged as powerful ingredients in skincare, offering a range of benefits from anti-aging to maintaining the skin barrier and beyond. Their ability to stimulate collagen production, stimulate hair growth, and promote healing makes them a valuable addition to any skincare routine. However, like all skincare ingredients, peptides are not without their limitations. Understanding how to choose and use peptide-based products effectively can help you maximize their benefits and achieve healthier, more youthful-looking skin.

Whether you’re looking to smooth out wrinkles, hydrate dry skin, or reduce redness, peptides offer a scientifically-backed solution that can deliver visible results over time. This comprehensive overview of peptides in skincare will help you make informed decisions when selecting peptides.