Should You Be Taking Collagen? What the Body Does With It and What the Evidence Shows

The video opens with a question: where would you expect to find collagen in the human body? The answer given is that it is found in all of these places, including the skin, tendons, ligaments, bones and the walls of blood vessels. The host describes collagen as the most abundant protein in the human body and an important structural component of many tissues.

Collagen has also become popular as a supplement, with claims that it can improve skin, reduce wrinkles, strengthen connective tissues, improve joints and help maintain bones as people age. The host notes that some of these claims seem to make sense, since if collagen is an important component of these tissues, consuming more of it might seem to supply what the body needs. The host then says "well, maybe," setting up the video's examination of what collagen is, how the body makes it and whether supplements provide meaningful benefits.

Collagen is a protein that makes up roughly 25 to 30% of all proteins in the body. Unlike many proteins inside cells, it is primarily extracellular, meaning it sits outside cells as an important part of the extracellular matrix, the structural framework that surrounds and supports cells in many tissues.

At the molecular level, a collagen molecule is made of three long amino acid chains wrapped around one another to form a triple helix. These chains contain especially large amounts of glycine and proline, along with a modified form of proline called hydroxyproline. Triple-helical molecules assemble into collagen fibrils, which then assemble into larger collagen fibers. Combined with cross-links between the molecules, this organization gives collagen tremendous tensile strength, making it extremely resistant to being pulled apart.

The host notes that depending on how it is measured, collagen can withstand tens of thousands of pounds of tensile force per square inch before failing. Some estimates put the tensile strength of collagen in a tendon at around 15,000 to 17,000 pounds per square inch. The host acknowledges that a collagen fiber is not actually one square inch in size, but says the figure still shows how strong the protein is.

The host says there are at least 28 different types of collagen, but the key point is that different types can be organized in different ways and combined with other extracellular matrix components to give tissues different mechanical properties. This explains why collagen is found in so many structures throughout the body.

In tendons, collagen fibers are arranged in parallel rows. With thousands of fibers organized this way, the parallel orientation can be seen, and it helps tendons withstand large tensile forces as muscles pull on bones to produce movement. Bone is described as a composite material: minerals, mainly calcium and phosphate in the form of hydroxyapatite, give bone much of its hardness and resistance to compression, while the organic portion contains large amounts of type 1 collagen that provides tensile strength and some flexibility and keeps the bone from becoming too brittle. Ligaments also contain large amounts of collagen, and collagen is found throughout many internal organs to support those structures.

In the second layer of the skin, the dermis, collagen is arranged differently from tendons. In a tendon, collagen fibers are arranged primarily in one direction. In the skin, the collagen forms a much more multi-directional network, which allows the skin to resist forces coming from all different directions while still maintaining some flexibility.

Collagen is constantly being remodeled in the body: older, damaged collagen is broken down while new collagen is produced to replace it. This makes collagen a dynamic tissue component that must be continuously maintained.

The host asks whether you need to eat collagen or take it as a supplement in order for your body to produce it, and answers no. Depending on the tissue, several cell types can produce it, but one of the most important is the fibroblast. Fibroblasts are found throughout connective tissues, and one of their major jobs is to produce collagen fibers and maintain the extracellular matrix. Because collagen is ultimately made from amino acids, as long as a person gets the proper amount of amino acids from any protein source, they do not have to ingest actual collagen.

Making functional collagen involves more than linking amino acids together. New collagen chains must undergo several modifications before they form the stable triple helix. One important modification requires vitamin C. Vitamin C is needed for enzymes that modify certain proline and lysine residues within the collagen chains through a process called hydroxylation, which the host describes as extremely important for collagen's formation and stability.

This is why a severe vitamin C deficiency can cause scurvy. Without enough vitamin C, the body cannot properly produce normal collagen, which can lead to bleeding gums, easy bruising, fragile blood vessels and poor wound healing. To make collagen, a person therefore needs enough amino acids from protein sources and vitamin C, but does not need to ingest actual collagen.

The host clarifies that ingesting collagen can happen in two ways. One is eating foods that contain collagen, which typically means animal connective tissues such as skins, tendons, ligaments and tougher cuts of meat. The other is taking collagen in the form of a supplement. As the host has already established, the body does not need to ingest actual collagen in order to make it, provided it gets amino acids from a protein source and adequate vitamin C.

If the body does not need ingested collagen to make its own, the host asks why collagen supplements are promoted. One idea is that taking collagen, especially as a supplement, could further increase collagen synthesis and make the process more efficient. The host then raises a potential problem: the body cannot absorb collagen. Fully intact proteins cannot be absorbed by the body, whether they are collagen or any other protein, so they must be broken down first.

The host walks through a collagen supplement's journey. After swallowing, it moves down the esophagus into the stomach, where stomach acid denatures the protein and certain enzymes begin breaking it down. The partially broken-down proteins then move into the small intestine, where more enzymes break them into individual amino acids and sometimes into dipeptides, two amino acids strung together, and tripeptides, three amino acids strung together.

The reason is that the intestinal tract can only absorb small molecules; fully intact proteins are too large. So the collagen from the supplement has been completely broken apart before absorption. These amino acids and small peptides are absorbed through the mucosal lining of the small intestine. Some mucosal cells take a small amount of the amino acids for their own protein needs. The rest enter the bloodstream and travel to the liver, which uses some for its own proteins. Whatever remains is released into the bloodstream as part of the amino acid pool, which can be transported to tissues throughout the body.

The host summarizes the process: collagen is ingested, broken down, partly lost to intestinal and liver cells during absorption, and the remaining amino acids mix with others in the bloodstream. Some of those amino acids could be transported to a muscle fiber and used to make muscle protein instead of another collagen fiber.

The host stresses that the body does not selectively earmark amino acids from a collagen supplement for collagen production, such as for skin on the face. The body uses those amino acids for whatever it needs. Based on this, it would seem that collagen supplementation does not work, but the host says collagen is certainly not the magical supplement that many people claim. Getting enough amino acids and vitamin C is still more important than starting any collagen supplement.

The host asks why some research still claims benefits from collagen supplementation and what mechanism might explain it. Some dipeptides and tripeptides produced from collagen digestion can be absorbed intact, rather than only as single amino acids. Some of these peptides contain hydroxyproline, the modified form of proline that is an important collagen component.

Some research suggests that collagen-derived peptides containing hydroxyproline may do more than provide amino acids. They may act as signaling molecules that influence cells such as fibroblasts and potentially stimulate them to produce more collagen and other extracellular matrix components. The host says this means there is at least a plausible mechanism for effects beyond supplying amino acids, but a plausible mechanism is very different from demonstrating that something produces meaningful benefits in humans.

Collagen supplementation has been studied in several areas, including skin, joints, tendons, muscles and bones, and the results are somewhat mixed depending on the tissue and outcome. The skin is where some of the biggest claims are made. Multiple randomized controlled trials and earlier meta-analyses reported improvements in skin hydration, elasticity and wrinkles, so the evidence at first looks convincing.

A 2025 meta-analysis examined 23 randomized controlled trials involving nearly 1,500 participants. When all the studies were combined, collagen supplementation did appear to improve skin hydration, elasticity and wrinkles. However, when the researchers separated the studies by quality and funding source, those benefits disappeared. Higher-quality studies found no significant benefit, and neither did studies that did not receive pharmaceutical company funding.

Research on joints, tendons, muscles and bones is also mentioned. The host says some of it is interesting, particularly for certain joint and tendon outcomes, but overall the results are inconsistent. Differences in the types of collagen used, dosages, study populations, exercise programs and outcomes measured make it difficult to draw one sweeping conclusion about collagen supplementation.

The host concludes that collagen supplementation cannot definitively be called completely useless, since plausible mechanisms exist and some studies suggest potential benefits in certain situations. However, the evidence is too mixed and nowhere near strong enough to claim that simply taking collagen will rebuild the collagen in skin, joints, tendons and bones. Before considering a supplement, the host recommends focusing on something more fundamental: eating a well-balanced diet with adequate protein for the amino acids the body needs, along with the vitamins and minerals needed to make and maintain collagen on its own.