The ultimate guide to collagen types I, II and III (2025)

Collagenis the most common protein we have, making up around 30% of all the protein in our bodies.¹ It’s your key building block, found in our skin, bones, tendons and ligaments.²

Lately, collagen supplements are getting a lot of attention because of their potential to support overall health.^2-4 They usually contain the same types of collagen your body already makes, making it easier to boost your collagen game. Knowing which types to look for can help you pick the right supplement to match your wellness goals.

But remember, while collagen supplements seem promising, scientists still need to do more research to be sure of any benefits.⁴ Many of the existing studies are short-term and involve small groups of participants. Bigger, longer studies are needed to really figure out how helpful collagen can be.⁴

Type I collagen is the most abundant protein, making up about 90% of your body’s collagen.^2,3 It’s the main component ofbonesand helps form skin, tendons and ligaments.^2,3

Type I collagen is composed of densely packed fibres made up of smaller protein building blocks calledamino acids.⁴ These fibres give our skin its stretchiness and provide structural support to various tissues.^2,5

Collagen supplements often feature bovine (beef) or marine (fish) sources of type I collagen.^3,6 Both types arehighly bioavailable, meaning they’re easy for your body to absorb and use.⁷

Producers typically extractbovine collagenfrom cows’ hides, whilemarine collagenis usually sourced from fish skin and scales.^5,6

However, it’s important to note that current research doesn’t conclusively prove that taking type I collagen supplements will lead to these benefits. Since the body can’t absorb collagen in its whole form, it must be broken down into smaller amino acids and might not necessarily be used in the way natural collagen functions within the body.⁶

More high-quality research is needed to fully understand how collagen supplements work in the body and whether they have any positive effects on our health.

Here are some areas that researchers are investigating around the possible benefits of type I collagen in supplements:

Type II collagen is a major component of cartilage – the stuff that cushions the joints and helps them move smoothly.²¹ Even though there’s less of it than type I collagen in our bodies, it’s still important for keeping joints healthy.⁴

Type II collagen is made up of the same amino acids as type I collagen, but the difference is in how it’s built. While type I collagen forms thick, strong fibres, type II collagen has thinner fibres that weave into a loose, flexible network.^21,22 This helps cartilage stay strong and flexible – perfect for absorbing shocks in our joints.^4,22

Supplement manufacturers typically source type II collagen from animal cartilage.²¹

If you’re looking at type II collagen supplements, you might notice that the label says that they are either ‘undenatured’ (which is what we call collagen in its natural form) or ‘hydrolysed’. Hydrolysed collagen has been broken down into smaller amino acid chains through a process called hydrolysis. This process makes the collagen easier for the body to absorb and use.²³

Researchers are looking into whether taking type II collagen supplements could support joint health, including range of motion and pain reduction.^23-27 In particular, undenatured collagen could help improve knee joint flexibility and joint discomfort.²³

However, our bodies might not use the collagen from supplements the same way they do with the collagen we naturally make, so more research is needed to know for sure.²³

Type II collagen could help support joint health in the following ways:^23-27

• joint support: we know that natural type II collagen helps maintain healthy joint cartilage in the body, which reduces the wear and tear that can lead to joint painand inflammation. Some preliminary research suggests potential benefits of supplementation for joint health, but these findings aren’t conclusive
• joint pain reduction: early studies indicate that type II collagen supplements may reduce joint pain and discomfort. However, further research is necessary to confirm any pain relief benefits

Type III collagen often collaborates with type I collagen in connective tissues. You can find it in places like the intestines, muscles, blood vessels and the uterus. It plays a role in keeping these tissues strong and supporting both skin andheart health.^4,18,28

Unlike type I collagen, which forms thick fibres, type III collagen makes thin, branching fibres. These fibres create a supportive mesh-like scaffold that supports organs and tissues which need to be flexible yet strong – like blood vessels, skin and internal organs. They’re like a net that holds everything in place while allowing flexibility.²⁸

You’ll often see type III collagen in supplements and skincare products. However, evidence is much thinner compared to type I and type II collagen. It usually comes from bovine (cow) skin, pig skin or marine (fish) sources.^4,29

Like other forms of collagen, type III collagen is promoted for various benefits, but there is not enough concrete evidence for these benefits yet.

Type III collagen is being studied for the following bodily functions:

• skin elasticity: type III collagen works alongside type I collagen to keep your skin firm and elastic. While some experts suggest that type III collagen improves skin texture and elasticity, current research doesn’t conclusively demonstrate these effects for collagen supplements. More studies are necessary to explore this potential benefit⁷

While generally considered safe, collagen supplements aren’t for everyone. People with specificallergiesshould exercise caution. For example, those with fish or shellfish allergies should avoid marine-derived type I collagen, people with chicken allergies should give type II collagen a miss and those with bovine allergies should steer clear of bovine-derived type I and type III collagen.^30,31

Pregnant and breastfeeding women should consult a healthcare professional before taking any collagen supplements to ensure it’s safe to do so.

Additionally, people with religious dietary restrictions need to verify that collagen supplements comply with their dietary guidelines, such as being kosher or halal. People who take medication or have chronic illnesses should also consult a healthcare professional to avoid any adverse interactions.

If you follow a vegan and vegetarian diet, you can look forplant-based collagen alternativesorvegan collagen supplementsthat could help support the body’s natural collagen production. However, it’s worth noting that there’s less research on vegan collagen supplements.

Collagen types I, II and III each have their own important jobs in the body, helping different parts of our health. Type I collagen primarily supports skin, bones and tendons, type II collagen is essential for joint health and type III collagen is helpful for our skin, muscle and heart health.

But when it comes to collagen supplements, we still need more research to know if they provide the same benefits.

If you’re thinking about taking collagen supplements, it’s important to pick the right type for your health goals. Always check with a healthcare professional first, especially if you have underlying health conditions, allergies or are pregnant.