Updated on 25 October 2026.
Collagen is everywhere: skin, cartilage, bones, blood vessels. Yet few people know that your body makes it itself, continuously, from amino acids and with the help of vitamin C. Understanding how it is made changes the way you see collagen, and how you can support it.
≈ 30%
of our proteins are collagen
1 in 3
amino acids in collagen is a glycine
25 to 30
the age when production starts to decline
≈ 90%
of the body's collagen is type I
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Contents
Collagen, the body's structural protein
The word collagen comes from the Greek kólla, meaning "glue". The image is apt: collagen holds many tissues together and gives them cohesion. It is the most abundant protein in the body, accounting for around 30% of our proteins.
It is found in the skin, cartilage, bones, tendons, ligaments, blood vessels, gums and teeth. It forms the body's framework: it gives tissues their structure, their suppleness and their strength.
Several collagens, several cells
There is not just one collagen, but several types. Each is made by specialised cells, depending on the tissue:
Fibroblasts
skin and ligaments
type I and III collagens
Chondrocytes
cartilage
type II collagen
Osteoblasts
bones
type I collagen
Tenocytes
tendons
type I collagen
Smooth muscle cells
blood vessels
type III collagen
For reference, type I accounts for around 90% of the body's collagen. Type III accompanies it in the skin and blood vessels, and type II makes up most of the collagen in cartilage.
A protein made of amino acids
Collagen is made of three long chains of amino acids, wound together into a very strong triple helix. A single molecule contains more than 3,000 amino acids.
Three of them come up again and again in this structure. Glycine is present in one position out of three in each chain.
These are the main building blocks of collagen. Without enough of them, cells cannot assemble the chains.
How your cells make collagen
Making collagen is an assembly job, which takes place inside the cells and then around them:
Assembling the building blocks
The cell links amino acids (glycine, proline, lysine...) together to form long chains.
Stabilising the chains
Some prolines and lysines are modified: this is hydroxylation. This step, essential to the strength of the fibres, requires vitamin C.
Forming the triple helix
Three chains wind together, then the molecule is released outside the cell.
Building the fibres
The molecules line up and bond together to form fibres, which give tissues their strength.
In other words, collagen is not swallowed ready-made: it is assembled on site by your cells, from amino acids and with the help of vitamin C.
The key role of vitamin C
Vitamin C is involved at the heart of the process, at the hydroxylation stage. This is why it has health claims recognised by the European authorities.
Vitamin C contributes to normal collagen formation for the normal function of:
Unlike many animals, humans cannot make vitamin C: it has to come from the diet. To find out more, read our complete guide to vitamin C.
Why production declines with age
However, from the age of 25 to 30, our body starts to reduce its collagen production, and this decline increases with age. Our body gradually loses the ability to produce certain amino acids that go into the composition of the collagens produced by our cells. As a result, it can no longer produce enough collagen to meet our needs.
The key point: with age, it is not the cells that disappear, it is the raw materials that run short.
Ready-made collagen or collagen made by the body?
Ready-made collagen
Most collagen supplements are of animal origin: bovine, porcine or marine. They provide ready-made collagen, which the body must first digest, breaking it down into amino acids and small fragments, before it can use it.
The building blocks of collagen
A new logic is to provide the body directly with the building blocks it uses to make its own collagen, together with the cofactors it needs, such as vitamin C. This route follows how the body naturally works: supporting production, rather than providing a finished product that it will have to break down anyway. It also has the advantage of being 100% vegan.
GENESIS+: a new approach
GENESIS+ offers a new approach: supporting the natural production of collagen by your cells. GENESIS+ contains no collagen. It provides five amino acids that account for more than two thirds of the building blocks of collagens I, II and III**, combined with cofactors:
- glycine, L-proline, L-lysine, L-glutamine and L-arginine;
- vitamin C, which contributes to normal collagen formation;
- zinc, which contributes to the maintenance of normal skin, hair and nails;
- N-acetylglucosamine.
A 100% vegan formula, with no animal collagen, designed in France and made in Italy.
To understand this process in pictures, visit reveillezvotrebiosynthese.com (in French).
**Triple-helix regions, by number of residues; hydroxylated proline and lysine included. Calculated on the human reference sequences. Source: UniProt.
Frequently asked questions
Does the body really make its own collagen?
Yes. Specialised cells (fibroblasts, chondrocytes, osteoblasts, tenocytes) make it continuously by assembling amino acids. Vitamin C contributes to normal collagen formation.
At what age does collagen production start to decline?
From 25 to 30, and this decline increases with age.
Which amino acids make up collagen?
Mainly glycine, proline and lysine. Glycine appears in one position out of three in each chain.
What is the role of vitamin C in collagen?
Vitamin C contributes to normal collagen formation for the normal function of skin, cartilage, bones, gums, teeth and blood vessels.
Does GENESIS+ contain collagen?
No. GENESIS+ provides amino acids that are building blocks of collagen, and cofactors including vitamin C, to support the natural production of collagen by your cells.
