Collagen, Hyaluronic Acid, Glucosamine and Chondroitin Sulfate: What They Really Do in Your Body (And What Actually Works)?

There is a reason why collagen, hyaluronic acid, and chondroitin sulfate are “trending,” as they appear everywhere — from supplements to skincare products — but the problem is that most people don’t really understand what they do, how they work together, or what their body actually needs.

And like many things in nutrition and health, this isn’t about trends. It’s about understanding how the body works.

If we go back to a more ancestral way of eating, what did humans naturally consume? Whole animals. Skin, cartilage, connective tissue, slow-cooked broths. Those foods were naturally rich in the same compounds that today we try to recreate with supplements.

So, instead of asking ourselves “which supplement is better?”, the better question is: What function does each of these compounds serve within the body and how do they work together?

COLLAGEN

Collagen is the most abundant protein in the human body. It represents approximately 25–30% of all the protein in your body and acts as the structural scaffold for skin, bones, tendons, ligaments, cartilage, and blood vessels. Without sufficient collagen, tissues lose firmness, elasticity, and regenerative capacity.

What few people know is that, from the mid-20s onward, natural collagen production begins to decline at approximately 1% per year. This means that by 40, you may have already lost a significant portion of your synthesis capacity. Chronic stress, sun exposure, tobacco, excess refined sugar, and inflammation significantly accelerate that process.

Types of collagen: they’re not all the same

At least 28 types of collagen have been identified in the human body, but science has primarily studied three:

Type I Collagen — The beauty superstar

It constitutes approximately 80–90% of all collagen in the body. It is the main structural component of skin, bones, tendons, and teeth. It is the most studied type in relation to skin health and aging, and is obtained primarily from bovine sources (beef skin and bones) or marine sources (fish skin and scales). Both bovine and marine collagen, when hydrolyzed, are well absorbed and provide the amino acids necessary for collagen synthesis in the body.

Type II Collagen — The cartilage guardian

This type is found predominantly in articular cartilage. It’s the star when we talk about joint health. The non-denatured form (UC-II) works through a different mechanism than hydrolyzed collagen: rather than primarily providing structural amino acids, it acts by modulating the immune response associated with cartilage, which can help reduce joint inflammation. Clinical trials have shown measurable reductions in joint pain with its continued use.

From a dietary perspective, type II collagen is found primarily in cartilage-rich tissues: chicken feet, beef joints, cuts with connective tissue, and bone broths prepared from these parts.

Type III Collagen — Type I’s companion

Generally found alongside Type I, Type III also contributes to skin elasticity and is part of the structure of blood vessels, muscles, and organs. It is especially relevant in earlier stages of life and in tissues with high regenerative capacity.

From a dietary perspective, type III collagen comes from the same sources as type I: animal skin, cuts with connective tissue, bone broths, and natural gelatin. This makes sense, because in the body both types are usually present together and perform complementary functions in tissue structure and elasticity.

Not all types of collagen serve the same function within the body. Types I and III are more related to skin, hair, nails, and overall tissue structure. They provide firmness, elasticity, and support. Type II, on the other hand, is much more focused on cartilage. It has a more direct role when we talk about joints, movement, and wear.

But the body doesn’t function in isolation. It’s not about choosing one and discarding the others. When you combine different types of collagen, you’re supporting different parts of the same system at the same time. You’re working on both structure and function.

In simple terms: types I and III focus more on skin and structure. Type II is more specific for cartilage. And when you combine them, the approach is much more comprehensive. It’s not