Your body has been making its own collagen since before you were born, and it never really stops. Cells called fibroblasts assemble it continuously throughout your life. What changes with age isn't whether you can make collagen, it's how efficiently that assembly process runs, and whether it has the raw materials it depends on.
The basic recipe your body follows
Collagen's structure is unusually repetitive. Glycine occupies roughly every third position in the amino acid chain, making up about a third of the entire protein, with proline and its derivative hydroxyproline filling much of the rest.[1] Your body can synthesize glycine and proline on its own, but during periods of high demand, growth, wound healing, or simply keeping up with normal turnover, dietary intake of these amino acids becomes more relevant. Some researchers question whether your body's own production keeps pace during those windows.
Where vitamin C becomes non-negotiable
Newly formed collagen chains aren't stable on their own. Specific proline and lysine residues have to be chemically modified through a process called hydroxylation before the triple-helix structure can hold its shape. Two enzymes carry out this modification, prolyl hydroxylase and lysyl hydroxylase, and both require vitamin C as a cofactor to function at all.[1] Without adequate vitamin C, this step simply doesn't happen, and the collagen your body attempts to build stays unstable and structurally weak. That isn't a minor efficiency loss. It's the same biochemical failure behind scurvy, one of the clearest historical demonstrations of what happens when this single cofactor runs out. Our piece on why collagen supplements include vitamin C goes deeper into that mechanism.
Other nutrients doing supporting work
- Copper, required for lysyl oxidase, the enzyme that cross-links collagen fibers into strong, stable structures
- Zinc, supports multiple enzymes involved in collagen synthesis and turnover
- Adequate overall protein intake, supplies the broader amino acid pool collagen synthesis draws from, beyond just glycine and proline. Our piece on proteinmaxxing vs. fibermaxxing looks at how much protein matters day to day.
What slows this process down over time
Collagen synthesis is generally described as declining gradually starting in the mid-to-late twenties, though the exact rate varies by tissue and by person. Beyond age itself, UV exposure breaks down collagen faster than your body can replace it, and chronically high blood sugar drives a process called glycation, where sugar molecules bind to existing collagen and make it stiffer and less functional. None of these factors are things a supplement addresses directly. They sit upstream of supplementation entirely.
What to do with this
Since your body is doing this work constantly whether or not you supplement, the more direct lever is making sure it has what it needs to do that work well. Vitamin C is the clearest example, and the target is more modest than most people expect, an amount a single red bell pepper or a couple of calamansi covers on its own.[2] The RDA isn't a bare minimum to scrape by on. It's a sufficient amount to keep this process running, and most people who eat a normal amount of fruits and vegetables already meet it without trying. Beyond vitamin C, the other levers are just as concrete: enough dietary protein to supply the amino acid pool, reasonable sun protection, and keeping blood sugar in a normal range rather than letting it run high for long stretches. Collagen supplements can add specific peptides to this picture, covered in our piece on collagen peptides vs. whole collagen, but they're supplementing a process your body already runs well on its own, given the right materials, not replacing it.
