What Does Collagen Do to the Skin?

July 2026

Collagen is one of the most talked-about ingredients in beauty, but what does collagen do to the skin, and how can collagen skincare support a healthy-looking complexion?

Collagen is naturally found within the skin and plays an important role in helping it appear firm, smooth, and youthful. However, as we age, natural collagen levels gradually decline, contributing to visible signs of ageing such as fine lines, wrinkles, and loss of firmness.

To help us better understand collagen in skincare, we spoke with Kiehl's Skin Expert Calum, who explains how collagen works within the skin and what to look for when choosing the best collagen skincare products.

What is Collagen in Skincare?

Collagen skincare refers to products formulated with collagen, peptides, or collagen-supporting ingredients designed to improve the appearance of skin firmness, smoothness, and hydration.

You'll find collagen in a variety of skincare products, including moisturisers, serums and targeted topical treatments for the face. Collagen can also be ingested by specific supplement brands. Calum recommends,

“Supplements and topical products are very different. With supplements, you’re ingesting something. I always advise customers to consult a dermatologist or doctor before starting any supplements to ensure they’re appropriate for their lifestyle and health.”

Whether you choose topical skincare, ingestible supplements, or a combination of both, collagen-based products are increasingly being incorporated into beauty routines by those looking to support healthy-looking skin and address visible signs of ageing.

While collagen itself is an important structural protein, not all collagen skincare products work in the same way. Some formulas use collagen to help hydrate and smooth the skin's surface, while others use collagen peptides, which can help support the skin's natural processes and contribute to firmer-looking skin.

Read more about the difference between collagen and collagen peptides here.

What Does Collagen Do in the Skin?

To understand what collagen skincare does, it helps to first understand the role collagen plays naturally within the skin.

Collagen is the most abundant protein in the body and accounts for approximately 70–80% of the skin's dry weight¹. As a key structural component of the skin, it helps provide support and contributes to the appearance of firm, smooth and plump skin.

The types of collagen commonly associated with skin and beauty include:

• Type I Collagen – The most abundant form of collagen in the body and the primary type found in the skin. It helps support the skin's structure, strength and firmness.
• Type III Collagen – Often found alongside Type I collagen and helps support skin elasticity and resilience.
• Type II Collagen – Found primarily in cartilage and connective tissues. While commonly included in collagen supplements, it is more closely associated with joint health than skin health.

In younger skin, collagen is produced naturally and continuously. Over time, however, collagen production begins to slow as part of the natural ageing process. External factors, particularly UV exposure, can accelerate this decline, alongside other environmental stressors such as pollution.

As collagen levels decrease, skin may begin to appear less firm and elastic, while fine lines and wrinkles become more noticeable. UV rays can also damage elastin fibres, which help skin maintain its bounce and resilience, contributing further to visible signs of ageing.

Calum explains:

“UV rays come in two forms: UVB and UVA. UVB rays are the ones that burn; you feel them and see the redness. UVA rays are longer and penetrate deeper into the dermis. They travel through clouds, rain and glass, and they break down collagen. We can't see or feel UVA damage immediately, but it can show up years later as wrinkles and pigmentation. That's why it's important to apply a broad-spectrum SPF every day, even when you're indoors or when it's raining.”

This is why daily sunscreen is such an important part of any collagen skincare routine. By helping protect skin from UV-induced collagen degradation, broad-spectrum SPF can help support firmer, smoother and healthier-looking skin over time.

Collagen Skincare Benefits

Collagen in skincare has several benefits, including:

Helps Skin Appear Firmer

One of the primary collagen skin benefits is helping skin appear firmer and more resilient. A 2025 research paper³ suggests that collagen peptides used in skincare can help improve the appearance of skin firmness and elasticity, supporting a smoother, healthier-looking complexion over time.

Supports Smoother-Looking Skin

Collagen skincare products often help improve skin texture by providing hydration and helping to reduce the appearance of roughness. The result is skin that feels softer and looks smoother.

Improves Hydration

One of the key benefits of collagen creams is their ability to help boost hydration. Many collagen moisturisers combine collagen with hydrating ingredients such as glycerin, hyaluronic acid, and squalane, which help attract moisture to the skin and support the skin barrier.

Helps Minimise the Appearance of Fine Lines

Although collagen skincare cannot stop the natural ageing process, regular use can help soften the appearance of fine lines and wrinkles by improving hydration and supporting the skin barrier. A 2024 research paper⁴ suggests that collagen peptide-based skincare products can help improve skin elasticity and density while reducing the appearance of wrinkles over time.

Promotes a Healthy Glow

Well-moisturised skin tends to reflect light more evenly, helping create a radiant and healthy-looking complexion. For those looking for the best collagen for glowing skin, products that combine collagen peptides with hydrating ingredients may be particularly beneficial, as these formulas can contribute to skin that appears brighter, healthier, and more luminous.

Best Collagen Products for Skin

When choosing the best collagen products for skin, it's important to look beyond marketing claims and focus on the overall formula.

Calum explains:

"Many collagen creams simply moisturise and temporarily tighten the skin. For a collagen product to signal the skin effectively, it needs a peptide or polypeptide, which acts as a communicator."

When shopping for collagen skincare, it's also worth understanding the difference between collagen and collagen peptides. While collagen can help moisturise and smooth the skin's surface, peptides are smaller molecules that can help support the skin's natural functions.

Whether you're looking to target visible signs of ageing, improve hydration, or support firmer-looking skin, Kiehl's offers collagen-focused products that can be incorporated into your skincare routine.

Kiehl’s 1cc Collashot Plump Serum

Designed to target visible facial volume loss associated with ageing, lifestyle factors, or rapid weight loss, 1cc Collashot Plump Serum is powered by Collagen Polypeptide technology delivered through Kiehl's patented Supra-Liposome Technology.

This lightweight serum helps visibly plump and firm the skin while supporting the skin's natural collagen production for a fuller, more youthful-looking appearance. The formula also contains Vitamin B12 and Rhamnose, helping address visible signs of collagen loss while supporting smoother, healthier-looking skin.

Its fast-absorbing gel-to-serum texture layers seamlessly into your existing skincare routine and is suitable for all skin types.

Collagen Skincare Routine

If you're wondering how to build a collagen skincare routine, consistency is key. Alongside collagen-focused products, ingredients such as Vitamin C, Retinol, and SPF can help support healthy-looking skin.

Step 1: Cleanse

Start with a gentle cleanser to remove dirt, oil and impurities, such as Kiehl's Ultra Facial Cleanser. Cleansing helps prepare the skin for the products that follow, allowing active ingredients to absorb more effectively.

Step 2: Apply Your Go-To Serum

Layer any targeted serums suited to your skin concerns, such as Powerful-Strength Line-Reducing Concentrate with Vitamin C or Retinol Skin-Renewing Daily Micro-Dose Serum.

Calum recommends:

“Using Retinol together with a collagen product is like having two friends each calling the skin to make more collagen. The Retinol encourages your fibroblasts to produce more, while the polypeptide mimics the presence of collagen and helps the skin maintain volume. They complement each other beautifully, and we see great results when they’re used together.

Step 3: Your Collagen Treatment

Apply a collagen treatment such as 1cc Collashot Plump Serum to help support smoother, firmer-looking skin.

During the daytime, Better Screen UV Serum SPF 50+ can also be incorporated into your routine. Formulated with Collagen Peptide Fragments, it combines skincare benefits with broad-spectrum UV protection, helping support healthy-looking skin while defending against daily environmental stressors.

Step 4: Apply SPF (If applying in the morning)

If applying your routine in the morning, always finish with a broad-spectrum sunscreen to help protect skin from UV-related ageing.

Looking to add collagen skincare to your routine? Discover Kiehl's collection of collagen and peptide-powered formulas designed to help support smoother, firmer, and healthier-looking skin.