Collagen Types: The Important Differences Between I, II & III

Collagen is a highly abundant protein that is present throughout the body, where it helps maintain the shape of tissues and organs. The exact location it shows up in—and the amnio acids it contains—is dependent on the type. The most common are types I, II or III.

To support their collagen levels, people often reach for collagen supplements, which are used for skin, hair, joint, and bone health.* When choosing a collagen—be it grass-fed bovine or marine—you should look for what types of collagen it contains to see if it matches up with your needs. 

Type I collagen is the most common in the body, and it provides structure to skin, tendons, bones, ligaments, and other connective tissues. You can find it in both marine and bovine collagen supplements. It is especially abundant in the skin, where it's "responsible for keeping it pliable and young-looking," says Gretchen Frieling, M.D., a board-certified dermatopathologist.*

If you're taking a collagen supplement, you're getting type I collagen. However, most collagen supplements contain two types of collagen in them: those being type II and III. That's where the differences start to show up, as they have very different functions.

Type II collagen occurs in the cartilage found in the ribs, nose, larynx, and trachea. It also shows up in a special kind of cartilage found on many joint surfaces.

Fran E. Cook-Bolden, M.D., a board-certified dermatologist, says this type of collagen "supports joint health, but it hasn't really been shown to be that beneficial for the skin."* It may also work to manage symptoms of joint-related conditions such as osteoarthritis.* This type of collagen is found in marine collagen but not grass-fed bovine.  

One randomized clinical trial found that people who took a type II collagen supplement for 180 days saw support in their physical function and helped maintain pain and joint stiffness.* Another meta-analysis, which combined data from five previous studies, found that these collagen supplements supported joint stiffness2 in people with osteoarthritis, but it didn't improve their pain or physical function. 

Type III collagen works alongside type I in skin, ligaments, blood vessels, and joints too. Type III collagen is found in grass-fed bovine collagen but not marine. This type of collagen "promotes skin health and elasticity—or what gives you that bounce-back in the skin," says Cook-Bolden.*

Few studies, though, have looked at taking type III exclusively—or at least in the same way that there's been research done on type I and II—but some overall research points to the benefits of type III collagen. Most notably, research has found that type III collagen content in skin decreases with age; type I also decreased, but to a lesser degree, perhaps implying that type III might be more of a key factor in skin aging. While we don't know for sure if this is the case, we do know that type III collagen is very important for fibroblast function3.* Fibroblasts are what help us produce collagen itself, as well as elastin. These are vital in wound healing and overall skin health.*

Of the collagen supplements out there, collagen types I, II, and III are the most prevalent—they are also the most prevalent in our bodies. And each type plays a different role, meaning that it's important to know the difference when choosing what collagen supplement is right for you. Obviously other factors come into play—diet, being the main concern—but if you are looking for a more skin-supporting and full-body benefit supplement, you should consider a grass-fed bovine collagen.*