What Are Collagen Peptides: Collagen Vs Collagen Peptides Explained

July 2026

As we age, our skin naturally produces less collagen, which can contribute to visible signs of ageing such as fine lines, wrinkles, and loss of firmness. This has made collagen one of the most talked-about skincare ingredients, but many people still wonder: what are collagen peptides, and how are they different from collagen itself?

To help answer these questions, we spoke with Calum, Retail Education Executive at Kiehl's.

What is Collagen in Skincare?

Collagen is the most abundant protein in the body¹ and plays an important role in maintaining the structure of skin, hair, bones, and connective tissue.

In the skin, collagen acts like a support framework, helping skin appear firm, smooth, and resilient. However, collagen production naturally decreases over time. Environmental factors such as UV exposure, pollution, genetics, and lifestyle habits can also contribute to visible collagen loss.

As collagen levels decline, skin may begin to show signs of ageing, including:

• Fine lines and wrinkles
• Loss of firmness
• Reduced elasticity
• Thinner-looking skin
• Changes in facial volume

This is why collagen-focused skincare products have become increasingly popular among those looking to address visible signs of ageing.

What Are Collagen Peptides?

Collagen peptides are smaller fragments of collagen protein that have been broken down into shorter chains of amino acids.

In skincare, collagen peptides are used because they can interact more effectively with the skin's surface than whole collagen molecules. Rather than simply sitting on the skin, certain peptides can help signal the skin and support a healthier-looking appearance.

A 2025 dermatological research² study suggests that certain topical peptides can help support collagen production and improve visible signs of skin ageing, including wrinkles and skin firmness

As Calum explains,

"The key ingredient is collagen polypeptide, which mimics the fragments of human collagen. When applied topically, it signals to the skin, 'Collagen is present,' which encourages the skin to produce more of its own."

This signalling function is one of the key reasons collagen peptides have become a popular ingredient in modern skincare formulations.

What Do Collagen Peptides Do?

Many people ask, "What are collagen peptides good for?" or "What does collagen peptide do in skincare?"

While collagen peptides cannot replace the collagen naturally produced deep within the skin in the dermis, they can help improve the appearance of surface-level epidermal skin by:

• Supporting a plumper-looking complexion
• Softening the appearance of fine lines
• Improving the look of skin smoothness
• Helping skin appear firmer
• Supporting visible skin resilience

Calum explains:

"Collagen is produced in the dermis, the 'mattress' supporting the epidermis. Topically applied products can't reach the dermis, but they can work on the upper layers. Think of an old mattress with a dip; you can't rebuild the internal springs from the surface, but you can add a topper to make it feel more even. Polypeptides mimic collagen at the surface, which helps fill fine lines and soften the look of creases."

Difference Between Collagen and Collagen Peptides

Understanding the difference between collagen and collagen peptides can help you make more informed skincare choices.

As Calum explains:

"For a collagen product to signal the skin effectively, it needs a peptide or polypeptide, which acts as a communicator. Without peptides, a collagen cream may hydrate and smooth but it doesn't tell the skin to produce more collagen."

Are Collagen Peptides Better Than Collagen?

Rather than asking whether collagen peptides are better than collagen, it may be more helpful to think about how they work together. Calum says:

"Peptides are the best friend of collagen because they communicate with the skin, helping to maintain and rebuild structure."

Collagen and peptides serve different functions within skincare formulations. While collagen can help improve hydration and provide a smoothing effect, peptides can help support the skin's natural processes through signalling mechanisms. This is why many advanced skincare formulas combine both ingredients to maximise benefits.

Kiehl’s Collagen and Collagen Peptide Skincare Products

If you're looking to support visibly firmer, plumper-looking skin, Kiehl's offers products that help address some of the factors associated with collagen loss, including daily UV exposure and age-related changes in skin structure.

Kiehl's Better Screen UV Serum SPF 50+

Protecting collagen is just as important as supporting collagen production. Daily exposure to UV rays is one of the leading causes of premature skin ageing and can accelerate the breakdown of collagen and elastin within the skin.

Incorporating a daily SPF into your skincare routine can help protect existing collagen and prevent the appearance of premature fine lines, wrinkles and loss of firmness associated with photoageing.

For best results, apply your SPF every morning as the final step in your skincare routine.

Kiehl's Better Screen UV Serum SPF 50+ combines collagen peptide fragments with broad-spectrum sun protection, helping defend skin against UV damage while supporting a healthy-looking complexion.

Incorporating a daily SPF into your skincare routine can help protect existing collagen and prevent the appearance of premature fine lines, wrinkles and loss of firmness associated with photoageing.

For best results, apply your SPF every morning as the final step in your skincare routine.

The formula contains Collagen Polypeptide, which mimics fragments of human collagen, alongside Rhamnose, a plant-derived sugar that helps reduce visible signs of ageing associated with collagen loss.

After using this product twice daily

• 9/10 agree skin looks plumper*

• Skin appeared firmer from Week 1**

• Helped restore the appearance of facial volume loss associated with rapid weight loss*

• Visibly plumped and firmed the skin

*Self-assessment, 103 subjects. Average results after 4 weeks

**Self-assessment, 103 subjects. Results after 1 week of twice-daily use.

For a complete collagen-supporting routine, the 1cc Collashot Plump Serum can be paired with daily SPF protection, such as Better Screen UV Serum SPF 50+, helping to both support and protect the skin's collagen over time.

Now that you know the difference between collagen vs collagen peptides, discover our range to find the ideal product for your skin type and concerns. Callum says:

"When shopping for collagen products, don't buy just for the word 'collagen.' Look for formulas containing peptides that signal to the skin."

Choosing formulas that combine collagen with peptide technology can help ensure you're getting ingredients that not only hydrate the skin but also support a visibly firmer, plumper appearance.