The body produces 28 different types of collagen, each serving a unique purpose, such as providing structural support, reinforcing tissues, and facilitating durability and flexibility.
However, collagen production and function depend not just on dietary intake but also on digestive health, nutrient status, and lifestyle habits.
Discover the five primary types of collagen and learn what you can do to help naturally maintain healthy collagen levels.
What is collagen?
Collagen is the most abundant protein in the human body, making up roughly 30 percent of the body’s total protein content.
Collagens’ primary role is to provide structure and strength to tissues. In fact, the word collagen is derived from the Greek words kólla, meaning glue, and genes, which translates into forming or producing.
Thanks to collagen’s unique triple helix structure, it has remarkable physical strength, which allows it to withstand stretching and pressure, especially in tissues such as skin, tendons, and ligaments.
At the molecular level, the collagen triple helix, also referred to as tropocollagen molecule, contains three polypeptide chains, each comprising repeating units of amino acids.
Collagen contains all 20 amino acids, but its amino acid sequence follows a unique pattern depending on the collagen type and tissue location.
While glycine appears in every third position, making it the most abundant amino acid in collagen, proline and hydroxyproline also occur frequently, helping twist and stabilize the helix.
Collagen synthesis also depends on several nutritional cofactors, such as the vitamin C complex, copper, zinc, and manganese, all of which help stabilize the helix structure.
Once formed, collagen molecules assemble into different structures, typically fibrils or meshworks, depending on the collagen type. These structures reinforce strength, flexibility, and stability throughout the body’s connective tissues.
Watch the video below to learn more about the functions of the five primary types of collagen.
What does collagen do?
Collagen plays a vital role in maintaining the structure, strength, and function of nearly all connective tissues in the body, including skin, bones, teeth, cartilage, tendons, ligaments, and blood vessels.
It forms a supportive matrix that anchors skin cells, maintains tissue structure, and stabilizes organs and systems, helping to keep them properly positioned.
One of collagen’s key roles is providing tensile strength–the ability of tissues to stretch without tearing. This quality supports skin elasticity, joint flexibility, and the resilience of muscles, organs, and vessels under physical strain.
As collagen naturally breaks down with age, tissues may lose firmness and flexibility, contributing to visible skin aging and reduced structural support across the body.
The different types of collagen
Although all forms of collagen share the same basic triple-helix structure, their functions vary widely depending on how they’re arranged and where they appear in the body.
However, the vast majority of collagen in the human body is accounted for by just a few main types.
Here are the five primary types of collagen and their key characteristics
1. Type I collagen
Type I collagen makes up nearly 90 percent of the body’s total collagen and forms densely packed fibrils with exceptional tensile strength. In fact, gram for gram, type I collagen is stronger than steel.
This structural strength helps tissues resist tearing when stretched and provides critical scaffolding for those exposed to mechanical stress.
Type I collagen is abundant in skin, bones, teeth, tendons, ligaments, and the connective tissues that support internal organs.
2. Type II collagen
Predominantly concentrated in articular cartilage within joints, type II collagen helps cushion joints from compressive forces. Its structure plays a key role in maintaining flexibility and shock absorption within joints.
3. Type III collagen
Type III collagen forms reticular fibers, which are thin, branching networks that support the structure of soft tissues, such as the liver, spleen, bone marrow, blood vessels, and lymph nodes.
These reticular fibers allow tissues to expand and contract while maintaining their shape.
Type III collagen also contributes to wound healing and the growth of new tissues. It also regulates the diameter and arrangement of soft type I fibrils, helping ensure proper shape, strength, and elasticity.
4. Type IV collagen
Unlike other types, type IV collagen doesn’t form into long fibrils. Instead, it creates a thin, sheet-like network that forms basement membranes, which are supportive structures that help anchor cells to the underlying connective tissue.
These membranes help stabilize the layers of the skin and internal organs. They also assist with filtration and cell signaling, helping guide how cells grow, function, and stay organized.
5. Type V collagen
Type V collagen is a specialized form of collagen that helps regulate how other collagen fibers, especially type I, form and organize.
This is particularly important in tissues that require highly ordered collagen structures, such as the skin, cornea, placenta, hair, tendons, and connective tissue between cells.
By controlling the thickness and arrangement of collagen fibrils, type V collagen supports tissue strength, flexibility, and organization. For example, precise collagen alignment, shaped in part by type V, is essential for vision as it helps maintain corneal transparency.
What are collagen peptides?
Collagen peptides, also known as functional collagen peptides or hydrolyzed collagen, are short chains of amino acids derived from the breakdown of larger collagen protein molecules during digestion.
Because these peptides are smaller, they are easier for the body to absorb and are commonly found in supplement form, which are typically sourced from animals such as cows, pigs, chickens, or fish.
Collagen peptide supplementation has gained popularity for its potential benefits in promoting skin elasticity, joint function, and overall connective tissue health.
Signs you’re losing collagen
As the human body ages, its ability to produce collagen naturally declines.
According to a report published by the Cleveland Clinic, human collagen decline typically begins during the mid-twenties and gradually accelerates over time. Women often experience a sharp collagen decline after menopause due to hormonal shifts.1
Here are common signs you are losing collagen:
- Wrinkled, crepey, or sagging skin
- Hollowing around the eyes and cheeks
- Weak muscles and joint discomfort
- Stiff tendons and ligaments
- Reduced mobility
- Digestive or circulation changes
- Slow wound healing
These effects often develop gradually and may vary based on genetics, lifestyle, and nutritional factors.
Supporting your body with collagen-promoting nutrients and healthy habits can help maintain connective tissue integrity as you age.
What damages collagen?
Even though collagen is structurally stable, it’s not permanent. Existing collagen is constantly broken down by collagen peptidase enzymes and is rebuilt through a process called collagen turnover.
This renewal allows tissues to repair micro-damage and adapt to physical demands, helping maintain flexibility in skin, joints, and other connective tissues. But it also means collagen reserves are only as strong as the nutrients and metabolic support available to rebuild them.
Several factors can contribute to decreased collagen production, including nutritional deficiencies, poor dietary habits, oxidative stress, genetic factors, excessive sun exposure, and exposure to environmental toxins.
Over time, these influences may contribute to signs of skin aging, such as reduced skin hydration, dullness, and the buildup of dead skin cells that can interfere with skin renewal.
How to prevent collagen loss
To support natural collagen synthesis, it’s vital to focus on foods rich in essential amino acids, especially the amino acids glycine and proline, which are crucial for building collagen.
Bovine collagen sources such as bone broth, pasture-raised beef, gelatin, chicken skin, fish skin, eggs, and organ meats naturally provide these amino acids as well as the cofactors needed to help maintain healthy collagen levels.
That said, collagen maintenance depends on more than just eating collagen-rich foods.
“Many people eat enough protein but still struggle with collagen maintenance due to low stomach acid or sluggish liver function,” explains Dr Berg.
To promote efficient collagen production, it’s essential to support the systems responsible for breaking down and rebuilding proteins.
This includes maintaining healthy digestion, supporting liver function, and ensuring adequate intake of vitamin C, zinc, copper, and B vitamins, all of which are involved in collagen assembly and repair.
Citrus fruits, cruciferous vegetables, shellfish, parsley, eggs, and nutrient-dense organ meats naturally provide many of these cofactors and also support detoxification, an essential factor in maintaining the metabolic environment needed to support collagen production.
A Healthy Keto® diet and intermittent fasting can also help support normal metabolic function, which affects how well the body utilizes dietary collagen and may support collagen synthesis and healthier turnover.
The role of collagen supplements
Collagen supplements can be a helpful addition for those looking to increase their intake of collagen-building amino acids.
Many oral collagen products contain hydrolyzed collagen peptides, which are easier for the body to absorb and may support healthy connective tissue when paired with a nutrient-dense diet.
However, since collagen peptides aren’t complete proteins, researchers suggest that while they may be supportive, they shouldn’t replace high-quality food sources in the diet.
According to research published in Nutrients, up to 36 percent of daily protein intake may come from collagen peptides without compromising the indispensable amino acid balance, provided that total protein needs are met.2
This highlights that while supplementation may support collagen synthesis, it should complement, not replace, complete proteins from whole foods.
Key takeaways
The body produces 28 types of collagen, with types I through V making up the majority and playing key roles in supporting the structure of skin, joints, bones, and organs.
Diet, digestive health, and liver function all influence how efficiently your body can produce and maintain collagen, and certain lifestyle and dietary choices may help support collagen maintenance.
To maintain collagen, eat high-quality proteins like organ meats and skin-on poultry, alongside cruciferous and vitamin C-rich vegetables. Following a Healthy Keto® diet and practicing intermittent fasting may further support collagen by enhancing digestion and nutrient absorption.
FAQ
What are the different types of collagen?
There are 28 collagen types. Type I, type II, and type III collagen comprise the vast majority and serve distinct structural roles in skin, bone, cartilage, blood vessels, organs, and connective tissues.
What form of collagen is most effective?
When choosing a supplement, hydrolyzed collagen peptides may be the easiest form for the body to digest and absorb.
Additional natural food sources that provide collagen include bone broth, gelatin, chicken skin, fish skin, slow-cooked meats, and organ meats.
What happens to collagen as I age?
Over time, the body produces less collagen and breaks it down more rapidly, which may contribute to reduced skin firmness, less joint flexibility, and slower skin renewal
Does eating collagen-rich foods increase the collagen in my body?
While collagen-rich foods don’t directly provide collagen to your tissues, they supply key amino acids like glycine, proline, and hydroxyproline, along with other nutrients needed to build collagen.
Pairing these foods with essential cofactors, such as vitamin C, copper, zinc, manganese, and B vitamins, can further support collagen synthesis.
