Collagen is the most abundant protein in the human body. It makes up 25-35 percent1 of all the protein in human tissues. The structure of collagen is made of rope-like strands of amino acids that tie together in a triple helix. The most common amino acids in collagen are proline, glycine, glutamine and arginine.
Ligaments, tendons and skin all contain a significant amount of collagen and collagen is often referred to as the body's scaffolding because it gives tissues structure.
When humans age, their natural collagen production diminishes. The decline can be as quick as one percent per year2. Under a microscope, collagen fibers in aging skin look sparser and less organized than the fibers in younger skin.
When humans consume collagen, enzymes in the stomach break down the molecules into smaller chains of proteins. Some collagen supplements, called hydrolyzed collagen, come already broken down for better bioavailability.
Collagen supplements3 may improve gut health, ease joint pain, strengthen hair, strengthen nails and improve skin health.
Types of Collagen
There are at least 28 types of collagen but type I, II and III make up more than 80 percent percent of the collagen in the human body.
Type I collagen
Type I collagen is the most abundant and strongest type of collagen. It’s the main structural component in tendons, ligaments, organs and skin. It provides structure to bones and teeth as well as gives skin its elasticity. It makes up about 80 percent of the collagen in human skin.
Type II collagen
Type II collagen is the main structural component in cartilage found on the surface of joints. It gives cartilage its shock absorbing ability and supplementation can reduce age-related joint pain. This type of collagen also gives structure to eyes.
Type III collagen
Type III collagen gives skin its firmness. It also forms the structure of blood vessels and the human heart. Type I and type III collagen are more similar to each other than to type II collagen. These fibers are often found in the same places in the body.
Benefits of Collagen Supplements
Taking a collagen supplement helps to replenish collagen that declines with age. Collagen supplements may improve gut, joint, skin, hair and nail health.
Research2 shows that taking collagen can improve skin health by reducing dryness and wrinkles. Taking collagen may stimulate the body to produce collagen. Supplementation may also stimulate the body to produce elastin, which gives skin its ability to retain its shape even when stretched.
One study3 found that 2.5-5g of daily collagen supplementation improved skin elasticity and moisture in women over the age of 35. However, the study didn't reach statistical significance. Another study by the same researchers3 found women had a decline in wrinkles after eight weeks.
Collagen supplementation may also improve joint health4 and reduce the likelihood of developing osteoarthritis. Type 2 collagen is most prominent in cartilage tissue. Supplements with type II collagen may have the greatest effect on joint health. One study5 found that patients with knee osteoarthritis treated with type 2 collagen showed significant enhancements in daily activities such as walking up stairs and sleeping without pain compared to patients who took a placebo.
Collagen gives connective tissue around the digestive system structure. Research6 shows that people with inflammatory bowel disease have lower levels of serum collagen than healthy individuals. However, there's no specific research showing that collagen supplementation will improve gut health.
Collagen7 is also responsible for giving muscles structure. Up to 10 percent of muscle tissue is made from collagen. Research8 shows that collagen may reduce age-related muscle decline in elderly people.
Hair and Nail Health
Taking a collagen supplementation may help individuals looking to grow out their nails9. When nails are brittle, they break easily. However, a collagen supplement may increase nail strength and reduce the frequency of breaks. Hair can also become brittle when collagen levels are low. Taking a collagen supplement may also increase hair strength10.
Daily Recommended Allowance
There's no DRA for collagen. Humans can produce collagen by breaking down dietary protein and resembling the amino acids in that protein into collagen.
The biggest concern with collagen supplementation is the risk of heavy metal poisoning from contaminants found in the supplement. However, the risk of heavy metal poison is relatively low and can be mitigated by choosing high quality collagen products.
To maximize the benefits from taking a collagen supplement, one should take at least five grams per day. Taking 10 grams of hydrolyzed collagen may have benefits for skin health and joint health. Athletes or people with brittle hair and nails can take up to 15 grams per day. Many brands of powdered collagen supplements come with a 10-gram scoop.
How to Use Collagen
Collagen supplements come in several different forms. Each form of collagen protein has pros and cons.
Most collagen powders come in powdered form. Collagen powders easily dissolve into smoothies or other liquids and are relatively tasteless. Some collagen powders may be flavored and can be mixed with other protein powders. Collagen powders can also be heated and mixed into soups or broths.
Collagen products that come in capsule form allow for quick supplementation for people who don't have time to make a smoothie. Capsules are easier to transport and can be taken by themselves.
Liquid collagen is an alternative to collagen powder for people who plan to mix it with smoothies or in soups.
Some people opt for collagen injections to achieve younger looking skin and to reduce wrinkles. However, collagen injections come with the risk of allergic reaction or bruising and redness at the site of injection.
Symptoms of Collagen Deficiency
Most of the symptoms of collagen deficiency manifest in parts of the body with the highest composition of collagen. Collagen is naturally produced in the body so deficiency is usually caused by a specific health issue such as an autoimmune disorder11.
Production of collagen naturally slows with age12. Collagen supplementation may slow the decline but can't prevent it altogether.
Some of the most general symptoms of collagen deficiency include the following:
- Muscle Weakness
- Body Aches
- Joint Pain
- Overly wrinkled skin
- Chronically dry skin
Who Is at Risk of a Collagen Deficiency?
Most of the lifestyle habits that can decrease collagen production also have negative impacts on other aspects of human health. Collagen production declines with age but these factors can cause collagen to decline earlier in life.
A High Sugar Diet
A diet high in sugar13 can speed up the break down of collagen fibers. Sugar causes inflammation in the body and chronic inflammation has negative effects on collagen.
The following foods are high in refined sugar or high glycemic carbohydrates
- White bread
- Desserts (pies, cake, donuts)
- Sweet sauces
- Most fast food
- Prepackaged snacks
- Fruit juices
Chemicals in tobacco can damage collagen in the skin. Nicotine narrows blood vessels and reduces the number of nutrients that can get to the skin. Smoking also reduces the body's production of collagen. One study14 found that smokers produced between 18-22 percent less collagen than non-smokers.
Overexposure of skin to UV light15 can cause a premature breakdown of collagen. UV light exposure causes collagen fibers to break down and elastin fibers to build up. This increase in elastin causes wrinkles to form.
Several autoimmune disorders can lead to the breakdown of collagen fibers. These disorders include the following:
- Rheumatoid Arthritis
- Temporal Arteritis
Foods that Contain Collagen
The most common sources of collagen in the human diet are high-protein animal products. Bone broth is one of the most concentrated sources of collagen. Gelatin is also derived from the collagen found in the bones of animals.
Since the body first has to break collagen into individual amino acids, it may be more valuable to eat high protein foods like milk and eggs. Eating a balanced diet that's high in protein should provide enough collagen for healthy individuals.
Different sources of collagen provide different amounts of each type of collagen. Here are some of the most common collagen sources.
Bovine collagen is sourced from the skin, bones and muscles of cows. It provides mostly type 1 and 3 collagen.
Chicken collagen is highest in type 2 collagen, which the human body can use to build and repair cartilage. Chicken collagen may be most beneficial for people with joint problems.
Fish collagen contains mostly type 1 collagen. Fish collagen benefits joints, skin, organs and blood vessels.