Collagen — what we know, what we don’t

We sell a functional water with collagen. Which means you should get to know what collagen is, why the category has exploded, and where the research actually stands — including the parts that aren't flattering for us.

What collagen is

Collagen is the most common protein in the body. Roughly a third of all the protein you carry is collagen, and it's found in what holds you together: skin, cartilage, tendons, bone, blood vessels.

The body builds its own collagen from amino acids in food. That ability declines with age — how much and how fast varies between individuals, and the exact figures usually cited in marketing are less well-founded than they sound.

Collagen in supplements is something different from the collagen in your body. It's hydrolysed collagen — collagen broken down into short peptides so it can dissolve in liquid and be absorbed in the gut. The raw material comes from cattle, pigs or fish. So-called vegan collagen doesn't contain collagen at all — it contains building blocks the body can use to make its own, which is a different thing.

Where it comes from

Collagen isn't new. The word comes from the Greek kólla, glue — because that's what it was used for. Boiled hides and bones made glue long before anyone called it a protein.

The same process gives you gelatine. Aspic, broth, gelatine desserts: food people have eaten for centuries, and it's collagen, boiled. When the bone-broth trend arrived around 2015, it was in practice a rediscovery of it, in new packaging.

The supplement category is younger than that. It took off in the latter half of the 2010s and is today a global market worth around $6 billion. It's the fastest growth any protein product has seen, and it's driven almost entirely by skin, hair and nails.

What the research says

Here's where it gets honestly complicated.

The argument for is mechanistic. When hydrolysed collagen breaks down in the gut, it produces not just free amino acids but also small peptides — particularly prolyl-hydroxyproline — that can be measured in the blood afterwards. That's the basis for the idea that collagen might do something other proteins don't. A number of randomised trials at 2.5–10 grams per day over 8–12 weeks have reported improved skin hydration and elasticity.

The argument against is that you can't direct amino acids to the skin. The body builds what it needs, where it needs it. Collagen is also an incomplete protein — it lacks tryptophan.

And in 2025 a meta-analysis put pressure on the whole field. Myung and Park compiled, in the American Journal of Medicine, 23 randomised trials with 1,474 participants and found no clinical support for collagen supplements against skin ageing. The most uncomfortable finding wasn't the headline result but the breakdown: studies without industry funding showed no effect. The industry-funded ones showed an effect. When only higher-quality studies were counted, no significant effect on hydration, elasticity or wrinkles remained.

That's not the whole picture. Other meta-analyses in 2025 and 2026 still find statistically significant improvements, and criticism of Myung and Park centres partly on the fact that the number of truly independent studies is small in both directions. For joints and osteoarthritis, the evidence is weaker and more mixed than for skin.

Summed up: the question is open, the evidence is of uneven quality, and the funding-dependent split is a reasonable reason to be sceptical of the category's own numbers. Including ours.

What can't be claimed — and so what we don't claim

Within the EU, health claims must be authorised before they can be used. There is no authorised health claim for collagen. Applications have been reviewed and have not passed.

That means no one — not us, not anyone else — is allowed to say that the collagen you drink does anything for your skin. That includes implications: imagery or branding that builds the association counts the same as a sentence that states it outright.

So we don't say it. We say what's in the bottle, and how much. The rest is above, so you can form your own view.

How and why people use it

Collagen supplements are bought above all for skin, hair and nails. After that, for joints — often by people who train a lot or are past middle age. The market is heavily female-skewed, though the joint segment is more even.

It's usually taken daily, as a powder mixed into coffee or a smoothie, in capsules, or as a ready-made drink. Doses in studies typically sit between 2.5 and 10 grams a day, and effects — where reported — have required eight to twelve weeks of consistency.

The most common reason people give themselves isn't that they've read the research. It's that it's easy to add, that it feels like a reasonable addition, and that they want to do something. That's a perfectly understandable reason. We just think it should be an informed one.

Updated August 2026. We update this page when the evidence changes, whichever direction that goes.