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What is Collagen Type I and III? A Deep Dive into Skin, Hair, and Joint Benefits

Collagen supplements are everywhere now: in coffee, smoothies, and those tubs of powder lining health store shelves. What gets missed in a lot of quick marketing, though, is that collagen isn’t one single thing.

There are 28 different types of collagen in the body, and each has a slightly different job. For practical purposes, the two most relevant types for skin structure, hair and nail support, and connective tissue integrity are Type I and Type III.

If we understand what each type does (and why they’re often paired), it’s much easier to choose a supplement that fits what we’re actually trying to support.

What is Collagen, Really?

We can think of collagen as the scaffolding that helps hold the body together. It’s the most abundant protein in the body, making up roughly 30% of total protein, and it’s found throughout skin, bones, tendons, ligaments, blood vessels, and the gut lining.

Our bodies naturally make collagen, but production tends to decline over time. As levels drop, people often notice changes like less skin elasticity and more day-to-day stiffness in connective tissues, which is one reason collagen supplements have become so popular.

Supplementation can be a helpful option for some people, but it works best when we understand which collagen types we’re using and what they’re known for supporting.

Type I Collagen: The Foundation

Type I collagen is the most abundant form of collagen in the body. It accounts for roughly 90% of total collagen, so when research talks about collagen related to skin structure, bone matrix, or overall connective tissue support, Type I is often the main focus.

Here's what makes Type I special:

  • Tensile strength. Type I forms thick, dense fibers that provide mechanical stability. Think of it like the steel beams in a building: it's what keeps everything strong and upright.
  • Low turnover rate. Once Type I collagen is in place, it sticks around. It's durable and long-lasting.
  • Wide distribution. You'll find it in your skin, bones, tendons, ligaments, teeth, and connective tissues.

For skin specifically, Type I acts as the "architect." It creates that dense network of fibers in your dermis (the deeper layer of skin) that gives your face its firmness and smoothness. When Type I depletes, skin starts to sag and wrinkles become more pronounced.

Type III Collagen: The Elastic Partner

If Type I is the main structural framework, Type III is often described as a supportive partner that contributes to tissue flexibility and repair. It’s the second most abundant collagen type and is commonly found alongside Type I in many tissues.

Type III has different structural properties:

  • Elastic network. Rather than stiff fibers, Type III creates a more flexible, elastic mesh that can store and release kinetic energy.
  • Thin fibers with high turnover. These fibers are less durable but regenerate quickly: which is actually a good thing during healing.
  • Found in soft tissues. You'll find high concentrations in skin, blood vessels, muscles, intestines, and organs.

Type III collagen is sometimes called “juvenile collagen” because it’s more prominent during early growth and can be involved in the initial phases of tissue repair. In wound healing, for example, Type III tends to show up early, and then Type I becomes more dominant as the tissue remodels and regains strength.

That’s a big reason Types I and III are commonly paired in supplements: they’re naturally found together in the body and contribute to overlapping aspects of connective tissue structure.

The Skin Benefits: More Than Just Anti-Aging

Let's talk about what most people care about: skin health.

Type I and Type III together provide comprehensive support for your skin:

Firmness and structure. Type I builds the dense collagen matrix that prevents sagging. It's the reason young skin bounces back when you press it.

Elasticity and plumpness. Type III enhances the elastic properties of your dermis, giving skin that youthful, hydrated appearance. It's what makes skin look "full" rather than thin and papery.

Hydration. Collagen fibers help your skin retain moisture. When collagen depletes, skin loses its ability to hold water effectively: leading to that dry, dull look.

Fine lines and wrinkles. Collagen isn’t a quick cosmetic fix, but some research suggests that regular collagen peptide intake may support skin elasticity and hydration, which can help soften the appearance of fine lines over time.

In practice, consistency matters more than intensity. If collagen is going to make a noticeable difference for you, it typically comes from steady use alongside the basics (sleep, protein intake, and sun protection).

Hair and Nail Support

Your hair and nails aren't made of collagen directly: they're made of keratin. But here's the connection: collagen provides the amino acids your body needs to produce keratin.

Type I collagen specifically supports:

  • Stronger, thicker hair growth. The amino acids in collagen (particularly proline and glycine) are essential building blocks for keratin production.
  • Healthier nail beds. Brittle, peeling nails often indicate a protein deficiency. Collagen supplementation can help strengthen the nail matrix.
  • Scalp health. Since collagen supports skin health, and your scalp is skin, healthier collagen levels mean a healthier environment for hair follicles.

If you’ve noticed changes in hair fullness or nail strength over time, collagen may be one piece of the overall nutrition picture, especially since it contributes amino acids that the body can use for building and repair.

Joint and Connective Tissue Benefits

It’s also worth making one distinction before we talk joint support.

Type II collagen is the specialist for cartilage and joint cushioning. If joint health is your primary concern, you'll want to look for supplements that include Type II specifically.

That said, Types I and III still play crucial supporting roles:

  • Tendons and ligaments. Type I is the dominant collagen in these connective tissues. Stronger tendons and ligaments mean better joint stability overall.
  • Bone health. Type I provides the organic framework that minerals attach to in your bones. It's essential for bone density and strength.
  • Blood vessel integrity. Type III supports the walls of your blood vessels, maintaining their flexibility and resilience.

For comprehensive joint support, many people combine Type I/III supplements with Type II. They work synergistically: Type II for the cartilage itself, Types I and III for the surrounding structures.

Why Sourcing Matters (A Lot)

Not all collagen supplements are created equal. The source of your collagen affects its bioavailability, purity, and which types you're actually getting.

Marine collagen (from fish) is particularly high in Type I and is known for its excellent absorption rate. The smaller peptide size makes it easier for your body to use.

Bovine collagen (from cows) typically provides both Types I and III, making it a popular choice for comprehensive supplementation.

Bone broth naturally contains Types I, II, and III, though in varying and often unpredictable amounts.

Here's what we think matters most when choosing a collagen source:

  1. Transparency about sourcing. Where do the animals come from? How were they raised? Grass-fed and pasture-raised sources tend to have better nutrient profiles.
  2. Third-party testing. Collagen supplements should be tested for heavy metals and contaminants. This is especially important for marine collagen, where ocean pollution is a real concern.
  3. Hydrolyzed peptides. Look for "hydrolyzed collagen" or "collagen peptides" on the label. This means the collagen has been broken down into smaller molecules that your body can actually absorb and use.
  4. Minimal additives. Some collagen powders are loaded with artificial sweeteners, flavors, and fillers. The cleaner the ingredient list, the better.

Putting It All Together

Type I and Type III collagen work as partners in your body: one providing strength and structure, the other adding flexibility and elasticity. Together, they support your skin, hair, nails, and connective tissues from the inside out.

When you're shopping for collagen, here's the simple checklist:

  • For skin, hair, and nail support: Look for Types I and III together
  • For joint and cartilage health: Add Type II to the mix
  • For overall wellness: A combination of multiple types covers more bases

And remember: quality matters. Where your collagen comes from, how it’s processed, and what else is (or isn’t) in the formula all influence how well it fits into your routine and how consistently you’ll want to use it.

Collagen supplementation isn’t magic, but it can be a practical nutrition tool. When we give the body useful building blocks from sources we trust, we’re supporting the systems that already do the work of maintenance and repair.

If you're curious about what to look for in a quality collagen powder: and what red flags to avoid: we break it all down in our guide to Zentein collagen powders.

We wish you the best.

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