What Does Collagen 1 And 3 Do For Your Body?

Collagen is the most abundant protein in the human body. Type 1 and type 3 are the two most common forms, and together they build the scaffold that holds your skin, bones, tendons, and organs together. Type 1 dominates in bone, skin, and tendon, while type 3 is more flexible and shows up in blood vessels, organs, and early wound healing.

If you have ever looked at a collagen supplement label, you have probably seen these numbers. They are not marketing labels. They describe real structural proteins your body makes and uses every day. Understanding what each type does helps you separate biology from hype.

What Does Collagen 1 And 3 Do For Your Body?

Type 1 collagen provides tensile strength. It is the main structural protein in bone, skin, tendons, and ligaments. Think of it as the steel rebar in concrete — it resists stretching and holds tissue together under load.

Type 3 collagen provides a more delicate, flexible framework. It is abundant in blood vessel walls, the uterus, and internal organs. It also appears early in wound healing, forming a temporary scaffold that type 1 later replaces in many tissues.

Both types belong to the fibrillar collagen family, meaning they assemble into long rope-like fibers. The difference is in the fiber diameter and how tightly they pack. Type 1 fibers tend to be thicker and stronger. Type 3 fibers are thinner and more compliant.

In skin, type 1 makes up the bulk of the dermis — the thick middle layer. Type 3 is present in smaller amounts, more concentrated near the surface and around blood vessels and hair follicles. In bone, type 1 accounts for roughly 90% of the organic matrix. The mineral component (calcium phosphate) gives bone its hardness, but collagen gives it the ability to bend without snapping.

Where Are Type 1 and Type 3 Collagen Found in the Body?

The distribution of each type reflects its mechanical job. Type 1 appears where strength matters most. Type 3 appears where flexibility and structural support for soft tissue matter more.

• Type 1: bone, skin, tendons, ligaments, dentin (teeth), cornea, and scar tissue
• Type 3: blood vessels, uterus, liver, lungs, intestines, and early wound tissue
• Both types: skin (different layers and proportions), and many organ connective tissues

This overlap matters. In skin, for example, type 1 and type 3 work together. Type 1 gives the dermis its load-bearing strength. Type 3 contributes to the fine network around small structures. When researchers examine skin from older adults, they often find changes in the ratio of these two types, though the exact relationship between those changes and visible aging is still being studied.

In blood vessels, type 3 provides elasticity. This is why arteries can expand and recoil with each heartbeat. As people age, the proportion of type 1 to type 3 in vessel walls can shift, and this shift is associated with arterial stiffness. Whether that shift is a cause or a consequence of vascular aging is not fully settled.

How Does Your Body Make Collagen 1 and 3?

Your body assembles collagen from amino acids — primarily glycine, proline, and hydroxyproline. The process starts inside cells called fibroblasts (in skin and connective tissue) and osteoblasts (in bone).

The steps are well understood. Cells build a precursor molecule called procollagen. That molecule gets modified with the help of vitamin C, iron, and other cofactors. Then it gets exported from the cell and assembled into fibrils. Finally, cross-linking enzymes strengthen the fibrils into mature collagen fibers.

This is why severe vitamin C deficiency causes scurvy — without vitamin C, the collagen modification step fails, and connective tissues weaken. That mechanism is firmly established.

Collagen production peaks in early adulthood. After that, it gradually declines. The exact rate of decline varies by tissue, genetics, lifestyle, and other factors. This decline is one reason skin loses firmness and why some people develop joint discomfort with age. But the relationship between collagen decline and specific symptoms is not as straightforward as supplement marketing often suggests.

What Happens When Collagen 1 or 3 Is Deficient?

Genetic disorders that affect collagen production show how important these proteins are. In osteogenesis imperfecta, mutations in type 1 collagen genes cause bones that break easily. In Ehlers-Danlos syndrome, defects in collagen (often type 3 or type 1) lead to hypermobile joints, stretchy skin, and fragile blood vessels.

These are rare conditions. They are not the same as the gradual collagen decline that comes with normal aging.

Age-related collagen changes are different. The fibers become less organized. Cross-linking increases in some tissues and decreases in others. The skin becomes thinner. Tendons become stiffer. Bone density declines, especially after menopause in women.

These changes are real and measurable. What is less clear is how much you can slow or reverse them through diet, supplements, or lifestyle. Some interventions show promise in specific contexts. Others do not hold up under careful study.

Can You Increase Type 1 and Type 3 Collagen Naturally?

Your body makes collagen from the amino acids you eat. Eating enough protein provides the raw materials. Vitamin C, zinc, and copper are required cofactors. A diet lacking these nutrients can impair collagen synthesis.

But eating collagen itself — whether from bone broth, collagen peptides, or gelatin — does not directly become collagen in your skin or joints. Your digestive system breaks it down into amino acids and short peptides. Those fragments can be used to build new proteins, but the body does not prioritize them for collagen production over other protein sources.

That said, some research suggests that specific collagen peptides may have effects beyond just providing amino acids. Some studies have found modest improvements in skin elasticity or joint comfort with collagen peptide supplementation. The evidence is mixed. Study designs vary. Many are small or industry-funded. Results are not consistent enough to make firm recommendations.

What is well established: resistance exercise stimulates collagen synthesis in tendons and bone. This is one of the most reliable ways to support connective tissue health. Weight-bearing activity signals your body to maintain and rebuild bone matrix, which is mostly type 1 collagen.

Avoiding smoking matters too. Smoking damages collagen and elastin in skin and blood vessels through multiple mechanisms. This is well documented.

Does Collagen Type Matter in Supplements?

Most collagen supplements contain a mix of types, often labeled as “types 1 and 3” or “type 1 and 3 peptides.” Some products specify type 2 for joint cartilage, or type 1 for skin.

Here is what the evidence supports and what it does not:

• Collagen peptides are generally recognized as safe for most people when consumed as a food or supplement.
• Some short-term studies suggest modest benefits for skin hydration or joint discomfort, but results vary and long-term data are limited.
• No clinical evidence currently confirms that a specific type of collagen supplement is more effective than another for a given purpose in healthy adults.
• The body does not appear to “target” supplemented collagen to specific tissues based on the type on the label.

If you choose to try a supplement, know that you are experimenting with something that has some supportive evidence but not definitive proof. That is an honest summary of where the science stands.

Do Collagen 1 and 3 Levels Change With Age?

Yes. Collagen production declines with age in most tissues. Skin thickness decreases. Bone density drops. Tendons lose some of their elasticity. These changes are well documented.

The rate and timing vary widely between people. Genetics, hormones, nutrition, physical activity, and sun exposure all play a role. Menopause accelerates bone loss in women because estrogen supports bone-building activity. That is established.

What remains unclear is how much of this decline is inevitable versus modifiable. Some lifestyle factors clearly help — exercise, adequate protein, not smoking. Others are still being studied.

Be cautious of anyone who claims a supplement can “restore” collagen levels to what they were at 25. No study has shown that. Slowing decline is a more realistic goal, and even that is difficult to measure outside of a research setting.