What Happens To Collagen When You Swallow It

The Obvious Objection, And Why It Is Not The Whole Story

The standard criticism of collagen powders goes like this: collagen is a protein, your digestive system breaks proteins into amino acids, and those amino acids get used wherever your body decides — not helpfully rerouted to your face. Eating collagen no more builds skin collagen than eating a brick builds a wall.

That reasoning is basically correct about whole collagen. It is also not the end of the argument, because collagen supplements are not usually whole collagen.

What Collagen Peptides Actually Are

Most products sold as collagen are hydrolysed collagen peptides — collagen that has already been broken into short fragments before it reaches you. Some of those fragments, particularly ones containing hydroxyproline, do appear to survive digestion and turn up in the bloodstream intact.

The proposed mechanism is not that those fragments become your skin. It is that their presence acts as a signal — the body reads circulating collagen fragments as evidence that collagen somewhere is being broken down, and responds by increasing production. Whether that is what actually happens in people is still being argued about.

What The Trials Found

There are now a reasonable number of randomised trials on collagen peptides and skin, and several meta-analyses of them. The overall picture is modest positive findings on skin hydration and elasticity, mostly over eight to twelve weeks.

The reasonable summary is: probably a small real effect on hydration and elasticity, smaller than the marketing implies, and taking two to three months to appear.

The Other Route: Give The Body The Materials

There is a second approach that gets discussed far less, and it starts from a different question. Rather than sending collagen in, supply the things your body needs to make its own.

Collagen synthesis needs vitamin C as an essential cofactor, adequate protein for the amino acids, and a working cell-division machine to build the cells that produce it in the first place. That last part is where the B vitamins come in: Folate and Vitamin B12 are both required for the cell division that skin depends on, and Biotin carries an authorised role in maintaining normal skin.

This is the route Gelagen takes, and it is worth being clear about it — despite the name, it contains no collagen at all. The whole question is answered on the product page rather than hidden.

Which Should You Buy?

They are not really competitors and there is no rule against doing both. The thing not worth doing is buying one while believing it is the other, which is exactly what a name can cause.

The Part Neither One Fixes

Collagen breaks down for reasons no supplement addresses. Ultraviolet light is the largest by a distance — it degrades collagen directly and it is responsible for most of what people call ageing. Smoking is second. Sugar contributes through a process called glycation that stiffens collagen fibres.

Daily sunscreen does more for your collagen than any supplement in either column above, and it costs less. That is not a fashionable thing for a supplement site to write, and it is true.