Why our collagen patch contains no collagen

Collagen is the largest category in beauty from within, and one of the least examined. So it is worth setting out what the research actually supports, including the parts that are inconvenient for us.

What collagen is
Collagen is the most abundant protein in the body. It gives skin its structure, strength and firmness. From the mid-twenties, natural production begins to slow, which is part of why skin gradually loses firmness with age.

That much is not in dispute. What happens when you try to top it up is where the category gets vague.

The argument we are not going to make
You will often read that swallowing collagen is pointless because digestion breaks it apart. It is a tidy story, and it is not accurate.

Collagen is digested into small fragments, but some of those fragments survive intact. Tri- and dipeptides such as Gly-Pro-Hyp and Pro-Hyp have been measured in human plasma after ingestion, and in animal work the same peptides reach the skin itself, where they appear to stimulate fibroblast activity [1]. The absorption argument against oral collagen does not hold, and we are not going to lean on it.
The real question is not whether collagen peptides get in. It is whether they do anything measurable once there.

Where the evidence actually stands
Here the picture is genuinely uncomfortable for everyone selling collagen.

A 2025 systematic review in The American Journal of Medicine pooled 23 randomised controlled trials covering 1,474 people. Across all of them, collagen supplements significantly improved skin hydration, elasticity and wrinkles. Then the authors split the trials by who paid for them. In studies without industry funding, the effect disappeared. In studies rated high quality, it disappeared too. Their conclusion was that there is currently no clinical evidence supporting collagen supplements for skin ageing [2].

That finding has been contested in the same journal, on the grounds that several trials classified as independent were in fact run in-house by collagen manufacturers, which would weaken the comparison [3]. So the question is live rather than closed.
Our reading is that oral collagen peptides may do something modest, most plausibly for hydration, and that the dramatic claims made across the category are not supported by independent evidence. That is a less satisfying answer than either side would like.

Why there is no collagen in our patch
Now the part that decides the formulation.

An earlier piece in this series set out the rule that molecules under roughly 500 daltons cross skin more readily than larger ones [4]. Collagen weighs somewhere near 300,000. Hydrolysed collagen peptides, the form used in most supplements, typically run to several thousand.

Both are far beyond what intact skin will pass. The very smallest fragments, the collagen tripeptides, do come in under the size threshold, but size is necessary rather than sufficient. Skin is a lipid barrier, and it resists strongly water-loving molecules almost as firmly as large ones, which is the same constraint we described with creatine.
A patch cannot deliver whole collagen, whatever the label says.

So Collagen Pro does not contain collagen. It contains the materials your body uses to make its own. Amino acids including glycine and proline, which are the raw structural components. Vitamin C, which contributes to normal collagen formation for the normal function of skin, and which your body cannot produce collagen without, because it is a required cofactor for the two enzymes that stabilise collagen's triple helix [5]. Alongside those, botanicals including tremella, blueberry, black tea and seaweed extracts.

Supporting production rather than supplying the finished protein. It is the same logic as the NAD+ patch, for the same physical reason.

We would rather explain the constraint than pretend it does not exist.