What Is Collagen?

This protein keeps skin and joints healthy, but people produce less of it as they age

<p>Elena Noviello / Getty Images</p>

Elena Noviello / Getty Images

Medically reviewed by Susan Bard, MD

Collagen is a type of protein that humans and animals produce naturally. It’s a fiber that connects tissues, keeping them strong and resilient and preventing them from stretching. Some research shows that collagen can keep skin youthful and may reduce symptoms of arthritis, but many studies have been funded by the skin care industry, making the results questonable.

Natural collagen production decreases over time, but taking collagen supplements usually is unnecessary. Still, supplements may help in some ways.

Continue reading to learn more about collagen, including what it does and what you should know before taking collagen supplements.

<p>Elena Noviello / Getty Images</p>

Elena Noviello / Getty Images

Why Is Collagen Good for You?

Collagen is found throughout the body. It's a key part of bones, cartilage, muscles, tendons, and skin. Collagen is rigid, meaning it doesn’t stretch easily, which helps it provide structural support throughout the body.

Most people have heard about collagen's reported ability to lessen the effects of aging on the skin, but the protein is important for much more than just keeping skink smooth. Collagen keeps your bones strong and tissues healthy to allow you to keep moving.

Collagen makes up 30% of the protein in your body. You can get collagen from the foods you eat, but your body also produces its own collagen.

Types of Collagen in the Body

There are more than 28 different types of collagen, but they’re not all created equal. Type 1 is by far the most common. It makes up 90% of the collagen in your body. Here’s an overview of the five most common types of collagen:

  • Type 1: This is a dense, rigid type of collagen that provides structure to your skin, tissues, tendons, and bones.

  • Type 2: Type 2 makes up elastic cartilage, a material that supports your joints.

  • Type 3: Type 3 collagen is found in your arteries, organs, and muscles.

  • Type 4: This collagen is found deep within the layers of your skin.

  • Type 5: Type 5 collagen is found in the eyes, skin, and hair.

The different types of collagen have different molecular structures, which gives them varying levels of rigidity to perform various roles within the body.

Types of Collagen Supplements

Many skin care products and supplements boast that they include collagen. However, because cosmetics are largely unregulated in the United States, their benefits are difficult to verify.

Some research shows that collagen can have properties that help improve skin elasticity and smooth wrinkles caused by advanced age and environmental factors. However, most of the studies on collagen supplements were funded by cosmetics companies, raising an issue of bias. Scientists have called for more, independent research concerning collagen supplements.

One way to get supplemental collagen is by using topical treatments, such as serums and creams. However, dermatologists say that this method likely isn’t effective since collagen proteins aren’t found on the surface of the skin but within the dermis, the second layer of skin. When you apply collagen to the surface of the skin, it cannot penetrate to the dermis.

Another way to increase your collagen intake that may be more easily absorbed by the body is with collagen supplements. Supplements come in pill or powder forms and are usually made using hydrolyzed peptides or collagen peptides, tiny pieces of animal collagen.

Research suggests collagen peptides are “possibly effective” at improving skin hydration and elasticity and in smoothing skin, as well as improving joint pain and mobility from osteoarthritis. They’re also likely safe if taking 10 milligrams a day or less for under five months. Safety data are lacking for taking collagen longer than five months.

Research has concluded that collagen supplements are “possibly safe” and that side effects are rare. Side effects can include gastrointestinal impacts like an upset stomach or a bad taste in the mouth. However, since supplements are not federally regulated, their claims are not verified. Always confer with your healthcare provider before starting a new supplement.

Foods to Stimulate Collagen Production

In addition to taking collagen supplements, you can get collagen from the food you eat. Collagen is found in animal tissue. The following foods are especially high in collagen:

  • Beef, including brisket, pot roast, and other rougher cuts

  • Bone broth from fish or other animals

  • Fish skin

Gelatin is another source of collagen. Gelatin can be found in various processed food products, including the dessert Jell-O.

If you are vegetarian or vegan you can find nonmeat foods that encourage collagen production within your body. These include:

  • Soy

  • Legumes

  • Eggs

  • Nuts and seeds

  • Whole grains

  • Leafy green vegetables, such as spinach and kale

Collagen Changes From Aging

Humans naturally produce collagen within their bodies. However, the production of collagen begins to slow down in adulthood. Starting in your 20s, you produce 1% to 1.5% less collagen each year.

Researchers have found that collagen production peaks between about ages 25 and 34. After that, production decreases by 25% over the next 40 years.

Health conditions can also impact how collagen functions in your body. Collagen vascular diseases, also known as connective tissue diseases, happen when the immune system causes tissues containing collagen to become inflamed. Lupus and rheumatoid arthritis are examples of collagen vascular diseases.


Collagen is one of the most common types of protein found in the human body. Although it’s a beauty buzzword, collagen is about much more than just smooth skin. It helps keep your joints, bones, skin and muscles healthy. Collagen production drops with age, starting from its peak between about ages 25 and 34.

Scientists have not definitively proven any benefits for taking collagen supplements. However, some studies show that taking collagen can help improve your skin’s appearance and may improve some symptoms of arthritis.