What Is Collagen? Types, Functions and Sources

This guide explains collagen in plain language: what it is, what it does in your body, the different types, where it comes from and how supplements fit in. It also covers what research says and where the evidence is still unclear, so you can make your own informed choices.

What Is Collagen?

Collagen is a protein. In fact, it is the most abundant protein in the human body, making up roughly a quarter to a third of all the protein you have. The word comes from the Greek kolla, meaning glue, and that is a useful way to picture it. Collagen helps hold your body together.

It is found in your skin, bones, tendons, ligaments, cartilage, blood vessels and other connective tissues. Think of it as the scaffolding inside a building. You do not see it from outside, but without it the structure would not keep its shape or strength.

On a microscopic level, a collagen molecule looks like a tightly twisted rope. Three protein chains wind around each other to form what scientists call a triple helix. This rope-like shape is what makes collagen strong and able to resist stretching.

How Does Your Body Make Collagen?

Your body makes its own collagen every day. Cells called fibroblasts, found in connective tissue such as the deeper layer of skin, build it from amino acids. These are the small units that proteins are made of. Collagen is especially rich in three of them: glycine, proline and hydroxyproline.

To put these amino acids together properly, the body also needs a few helpers:

• Vitamin C, which is essential for stabilising collagen fibres. Without enough of it, the body cannot form healthy collagen. Scurvy, the disease caused by severe vitamin C deficiency, is a well-known example: wounds heal poorly and gums bleed.

• Zinc and copper, minerals that support the process.

• Enough protein overall, because amino acids come from the protein you eat, such as dals, eggs, dairy, fish, chicken or soy.

So collagen is not something you must eat in order to have. It is something your body builds from the food you eat.

What Does Collagen Do in the Body?

Collagen is mainly a structural protein. Its main jobs include:

• Giving strength to tissues. Tendons and ligaments, which connect muscle to bone and bone to bone, are largely made of collagen.

• Supporting skin. In the dermis, the thick layer beneath the surface of the skin, collagen helps give skin its firmness and structure, along with other proteins such as elastin.

• Forming part of bones and cartilage. Collagen provides a flexible framework in bone, and cartilage cushions your joints.

• Supporting blood vessels and organs. Certain collagen types help keep blood vessel walls and internal organs in shape.

• Helping wounds heal. Collagen plays a part in repairing damaged tissue.

Researchers also know that collagen is more than a building material. It sends signals to cells that influence how they grow and behave.

Types of Collagen

Scientists have identified at least 28 types of collagen, numbered with Roman numerals (I, II, III and so on). Most of the collagen in the body belongs to just a few of them. Each type has a slightly different structure and is found in different places.

Types I, II and III form long, rope-like fibres. Type IV works differently, forming a mesh-like sheet rather than fibres.

You will often see "Type I" or "Type I and III" written on supplement labels. It is worth knowing that the type named on a label does not, on its own, tell you how well a product works. Product composition depends on the source and how it is processed. We cover this in more detail in our guide to collagen types.

Why Collagen Levels Change Over Time

Your body makes plenty of collagen when you are young, but production slows gradually with age. The existing collagen can also break down faster over time. Several everyday factors are linked to faster collagen breakdown:

• Long-term, unprotected sun exposure (UV rays damage skin collagen)

• Smoking

• A diet low in protein or in vitamin C

• Natural ageing and hormonal changes

This is why many people become interested in collagen as they get older. However, a drop in the body's own collagen does not automatically mean a supplement is the answer. Sun protection, not smoking, good nutrition and regular movement all matter for the health of your skin and joints.

Where Does Collagen Come From?

1. Your own body

For most healthy people, this is the main source. The body builds collagen from the protein in your diet along with vitamin C, zinc and copper.

2. Collagen-containing foods

Collagen is found in the connective tissue of animals. Foods that contain it include:

• Bone broth and meat stock

• Chicken with skin and cuts of meat with connective tissue

• Fish with skin

• Gelatin, which is cooked collagen

One important point: when you eat collagen, your body does not carry it straight to your skin or joints. Digestion breaks it down into amino acids and small chains of amino acids called peptides, like any other protein. Your body then uses these pieces wherever it needs them.

3. Foods that help your body make its own collagen

Since the body builds collagen from nutrients, a balanced diet is a practical starting point. Some examples that are easy to find in India:

• For vitamin C: amla (Indian gooseberry), guava, oranges, lemon, tomatoes, capsicum and broccoli

• For protein: dals, rajma, chana, eggs, paneer, curd, soy, fish and chicken

• For zinc and copper: pulses, nuts, seeds and whole grains

For vegetarians and vegans: collagen itself comes only from animals, so plant foods do not contain it. A varied plant-based diet can still supply the amino acids and nutrients the body needs to make its own.

4. Collagen supplements

Supplements are usually made from animal sources such as fish skin and scales (called marine collagen), cattle, chicken or pig. They commonly come as powders, capsules or drinks.

Most are "hydrolysed", which means the collagen has been broken into smaller pieces called collagen peptides. This makes the powder easier to mix and take, but as noted above, your digestive system still processes it as protein.

What Does Research Say About Collagen Supplements?

This is where it is important to be honest: the evidence is mixed and still developing.

Some reviews of clinical trials have reported small improvements in skin hydration and elasticity in people taking collagen peptides for a few months. However, a 2025 meta-analysis published in The American Journal of Medicine, which combined 23 randomised trials, found that these benefits did not hold up when it looked only at higher-quality studies or studies not funded by supplement companies. Supporters of collagen research have questioned whether funding alone should lower confidence in a study, so the debate continues.

Research on joints and bones is also mixed, and many studies are small, short or use different products and doses, which makes them hard to compare.

What this means for you:

• Collagen supplements are not a proven fix for aging, wrinkles or joint problems.

• Results, if any, vary from person to person and cannot be guaranteed.

• Supplements work alongside, not instead of, a balanced diet, sun protection and healthy habits.

If you are curious about supplements, a sensible approach is to read the label carefully, check the source and serving size, and speak with a doctor or registered dietitian first. You can browse our collagen range to see how product information is presented, including ingredients and serving details.

Frequently Asked Questions

Is collagen a protein? 

Yes. Collagen is a structural protein made of amino acids, and it is the most abundant protein in the body.

Can the body make collagen on its own?

 Yes. The body builds it from amino acids, with the help of vitamin C, zinc and copper. A balanced diet supports this.

Which type of collagen is the most common?

 Type I is the most common, found in skin, bones, tendons and ligaments.

Does eating collagen increase collagen in my skin?

 Not directly. Collagen from food or supplements is digested into amino acids and peptides first. How these are then used by the body is still being studied.

Do I need a collagen supplement?

Most healthy people who eat a balanced diet do not need one. Whether a supplement suits you depends on your diet, health and goals, so it is best to talk to a healthcare professional.

Is collagen suitable for vegetarians?

 No. Collagen supplements come from animal sources. Plant-based diets can support the body's own collagen production through protein and vitamin C, but they do not contain collagen itself.

Key Takeaways

• Collagen is the body's most abundant protein and works like scaffolding for skin, bones, joints and other tissues.

• There are at least 28 types. Types I, II and III are among the most common.

• Your body makes its own collagen from protein, vitamin C, zinc and copper.

• Eating collagen does not mean it goes directly to your skin or joints, because it is digested like any other protein.

• Research on supplements is mixed. Benefits are not guaranteed.

This article is for general information and education only. It is not medical advice and is not meant to diagnose, treat, cure or prevent any disease or health condition.