Collagen is the most abundant protein in the human body and an important structural component of skin, bones, cartilage, tendons and other connective tissues. Discover what collagen is, the different types of collagen, how collagen changes with age, dietary sources and what current research tells us about collagen supplements.
Collagen is the most abundant protein in the human body and an important structural component of skin, bones, cartilage, tendons and other connective tissues. Discover what collagen is, the different types of collagen, how collagen changes with age, dietary sources and what current research tells us about collagen supplements.
Brittany Lubeck is one of Lily & Loaf’s trusted wellness experts, helping people achieve balanced, healthy lifestyles through evidence-based nutrition. As a Registered Dietitian Nutritionist (RDN), she specialises in turning complex health information into practical, real-world advice.
With experience in community wellness, sports nutrition, and oncology, Brittany takes a holistic approach to nutrition, combining whole foods, supplementation, and sustainable habits. She ensures our content is fact-checked and aligned with the latest scientific research, empowering you to make informed choices for long-term well-being.
This article has been reviewed by Brittany to provide accurate, expert-backed insights you can trust.
What Is Collagen?
Collagen is the most abundant protein in the human body, accounting for around one-third of its total protein. It is a hard, fibrous protein found throughout connective tissues, where it helps provide structure to skin, bones, tendons, cartilage and teeth(1).
The body produces collagen naturally from amino acids obtained through the diet, alongside nutrients involved in normal collagen formation. However, collagen production and the structure of existing collagen can change with age and may also be influenced by lifestyle and environmental factors.
There are 28 identified types of collagen, although types I, II and III are among the most abundant and widely studied in the human body(2). Different collagen types have different structures and are found in different tissues.
Types of Collagen
There are 28 identified types of collagen, with types I, II and III among the most abundant in the human body(2). Each type has a different structure and is found in different tissues throughout the body.
Type I Collagen
Type I is the most abundant form of collagen, accounting for more than 90% of the body's collagen. It is found in tissues including the skin, bones, tendons, ligaments and teeth, where its densely packed fibres provide structure and strength(9).
Type II Collagen
Type II collagen is found primarily in cartilage, including the cartilage within joints. Its structure differs from type I collagen and helps provide the framework and cushioning properties associated with cartilage(10).
Type III Collagen
Type III collagen is found in tissues including blood vessels, muscles and internal organs. It is often present alongside type I collagen and contributes to the structure of a range of softer and more flexible tissues(11).
What Does Collagen Do in the Body?
Collagen is a structural protein found throughout the body. Different types of collagen form part of skin, bones, cartilage, tendons, ligaments, muscles, blood vessels and other connective tissues.
In the skin, collagen is an important component of the dermis and contributes to its structure and strength. In bones, collagen forms part of the structural framework of bone tissue, while collagen within cartilage contributes to its physical structure. Collagen is also present in muscle tissue and forms part of the structure of blood vessels.
What Does Research Say About Collagen Supplements?
Research into collagen supplementation has explored a number of areas, including skin, joints, bones and musculoskeletal health. However, findings vary depending on the type of collagen used, the amount taken, the study population and the outcome being measured.
Skin
Research has investigated oral collagen supplements in relation to skin ageing, hydration and wrinkles. Some clinical studies and reviews have reported improvements in measures such as skin hydration and wrinkle appearance, although results should be interpreted in the context of the specific collagen preparations and study designs used(3).
Joints
Collagen supplementation has also been studied in relation to joint health, including osteoarthritis. Research has examined different forms and compositions of collagen, with some studies reporting changes in measures of joint discomfort and function(4).
Bones and Musculoskeletal Health
Research has explored collagen peptides in relation to bone and musculoskeletal health. Studies include work involving postmenopausal women and research examining the potential role of collagen protein alongside physical activity(12,13).
Heart Health
Collagen provides structure to your arteries, the blood vessels that carry blood from your heart to the rest of your body. Some studies suggest that collagen supplementation may help prevent atherosclerosis(14).
Top Ten FAQs - Collagen
What is collagen?
Collagen is the most abundant protein in the human body, accounting for around one-third of its total protein. It is a major structural component of skin, bones, tendons, cartilage and other connective tissues(1).
What are the different types of collagen?
There are 28 identified types of collagen, although types I, II and III are among the most abundant in the human body(2). Type I is widely found in skin, bones, tendons and ligaments, type II is primarily associated with cartilage, and type III is found in tissues including blood vessels, muscles and internal organs.
What happens to collagen as we age?
Collagen production and structure change naturally with age. These changes can become particularly noticeable in the skin, where reduced collagen is associated with changes in firmness and elasticity and the development of visible signs of ageing such as wrinkles(3).
What is hydrolysed collagen?
Hydrolysed collagen is collagen that has been broken down into smaller fragments known as collagen peptides. This is a common form used in collagen supplements(16).
What is the difference between bovine and marine collagen?
The main difference is their source. Bovine collagen is derived from cattle, while marine collagen is generally derived from fish. Different sources can also provide different proportions and types of collagen, so it's useful to check both the source and collagen types when comparing supplements.
Can collagen supplements help with joint pain?
Research has investigated collagen supplementation in relation to joint health, including osteoarthritis. Some studies have reported changes in measures of joint discomfort and function, although results can vary according to the type and composition of collagen used(4).
What are the potential side effects of collagen supplements?
Collagen supplements are generally considered well tolerated, although reported side effects can include digestive discomfort, an unpleasant taste and headaches(5). People with food allergies should also check the source and other ingredients before choosing a collagen supplement.
Is collagen vegan?
No. Collagen itself is derived from animal sources and is therefore not vegan or vegetarian. Products described as vegan collagen-support or collagen-building supplements do not contain traditional animal-derived collagen and instead typically provide nutrients involved in the body's own collagen production.
Can collagen supplements support hair and nails?
Research into collagen supplementation for hair and nails is still developing. Studies have investigated specific collagen peptides in relation to brittle nails, while other research into hair has included laboratory and animal models, so further human research is needed before firm conclusions can be drawn(6,7).
What should I look for when choosing a collagen supplement?
Consider the source of the collagen, the collagen types provided, the amount per serving and whether the collagen is hydrolysed. It's also worth checking the full ingredient list, any additional nutrients included in the formula and whether the product is suitable for your dietary requirements.
Collagen and Ageing
Collagen production changes naturally as we age. These changes can become particularly noticeable in the skin, where reduced collagen is associated with changes in firmness and elasticity and the development of visible signs of ageing such as wrinkles(3).
Lifestyle and environmental factors may also affect collagen over time. Exposure to ultraviolet radiation and smoking are among the factors associated with collagen breakdown, making overall lifestyle an important part of looking after skin and connective tissues as we age.
Supporting Normal Collagen Formation
The body produces collagen naturally using amino acids obtained through the diet, alongside nutrients required for normal collagen formation. A varied, balanced diet can therefore provide many of the nutritional building blocks involved in this process.
Diet and Vitamin C
Protein-rich foods provide amino acids that the body can use to make proteins, including collagen. Vitamin C also has an important role, contributing to normal collagen formation for the normal function of skin, cartilage and bones.
Foods containing vitamin C include citrus fruits and a wide variety of other fruits and vegetables. Research has also investigated the relationship between vitamin C and type I collagen synthesis(15).
Collagen Supplements
Collagen supplements provide collagen from external sources and are available in several forms. Many contain hydrolysed collagen, also known as collagen peptides, where collagen has been broken down into smaller peptide fragments(16).
Collagen supplements can also differ according to their source. Bovine collagen is derived from cattle, while marine collagen is generally derived from fish. The collagen types and composition can therefore differ between products, making the source, type and amount of collagen useful things to consider when comparing supplements.
Food Sources of Collagen
Collagen occurs naturally in animal connective tissues. Bone broth, which is produced by simmering animal bones and connective tissues, can contain collagen and collagen-derived proteins. However, its composition can vary considerably depending on the ingredients and preparation method.
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Potential Side Effects and Suitability
Collagen supplements are generally considered well tolerated, although reported side effects can include digestive discomfort, an unpleasant taste and headaches(5).
Because collagen supplements are commonly derived from animal sources, it's important to check where the collagen comes from. People with food allergies should pay particular attention to the source and other ingredients in a product, particularly with marine collagen derived from fish.
Traditional collagen itself is animal-derived and is therefore not suitable for vegan or vegetarian diets. Products marketed as vegan “collagen” or collagen-support products do not contain animal-derived collagen and instead typically provide nutrients intended to support the body's own collagen production.
The Bigger Picture
Collagen is the most abundant protein in the human body and forms an important structural component of skin, bones, cartilage and other connective tissues. While the body produces collagen naturally, its production and structure change throughout life, particularly as we age.
A varied, balanced diet provides the protein, amino acids and nutrients the body needs for normal physiological processes, including collagen formation. Vitamin C has a recognised role in this process, contributing to normal collagen formation for the normal function of skin, cartilage and bones.
Collagen supplements provide another dietary source of collagen and are available in different forms, types and sources. When choosing one, consider the amount of collagen per serving, whether it is hydrolysed, its animal source, the collagen types provided and any additional nutrients included in the formula.
Lily & Loaf Hydrolysed Collagen+ provides 8,700mg of hydrolysed bovine collagen peptides per daily serving, supplying type I and III collagen alongside 96mg of vitamin C.
León-López A, Morales-Peñaloza A, Martínez-Juárez VM, Vargas-Torres A, Zeugolis DI, Aguirre-Álvarez G. Hydrolyzed Collagen-Sources and Applications. Molecules. 2019;24(22):4031. doi:10.3390/molecules24224031
This guide has been fact-checked by Brittany Lubeck, a Registered Dietitian Nutritionist with expertise in Clinical Nutrition. The information provided is based on current scientific research and regulatory guidelines.
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