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What collagen is, and where it lives
Collagen is the scaffold of the skin: a network of fibres that gives it density, elasticity and hold. It lives in the dermis, the layer beneath the visible surface, and is made mostly of type I collagen, which gives strength, and type III, finer and more elastic.
It is built by fibroblasts, cells that anchor themselves to the fibres. That anchoring matters more than it seems: a cell stretched well over the network receives a mechanical signal that tells it to keep producing.
Why we lose it with age
A University of Michigan study compared the skin of people aged 18 to 29 with that of people over 80. The decline has two causes, and they add up. The first is the cell itself: in the lab, young fibroblasts produced 82 ng/ml of type I procollagen, old ones 56.
The second is the network. In young skin 78% of the fibroblast surface was attached to the fibres, in old skin 58%. Less support means less tension, and less tension means less new collagen.
The process feeds itself. The enzymes that break down the matrix, metalloproteinases, fragment the fibres; the fibroblast loses its grip, shrinks and makes even less collagen and even more enzymes. Sun exposure speeds all of this up. As early as the 1970s, measurements showed that skin collagen declines with age and is lower in women at every age.
That is why skin loses firmness long before wrinkles appear: the network loosens quietly, beneath the surface.
What «stimulating collagen» really means
«Stimulates collagen» has been printed on too many jars to mean much anymore. Yet the mechanism is real and precise: fibroblasts get back to work when they receive a signal in the deep layers of the skin, where the network lives.
The signal can be thermal, like the controlled heat of radiofrequency and lasers; mechanical, like the microparticles of biostimulators; biological, like polynucleotides or the growth factors in PRP. In heat-treated tissue a stress response comes first, then the recruitment of fibroblasts that make new collagen, and finally the remodelling of the network.
The response is slow. It takes weeks, because the body builds new collagen fibre by fibre.
Creams and supplements: what really gets there
Skin is a barrier, and a good one. A substance must weigh less than about 500 daltons to cross the outer layer; collagen weighs hundreds of thousands. Collagen applied to the skin stays on the surface: it can hydrate, but it does not reach the network built further down. Some small molecules are the exception, such as prescription retinoids, which also act on the dermis.
Supplements are a different case, because hydrolysed collagen is taken by mouth. A meta-analysis of 19 randomised trials in 1,125 people and a more recent one of 10 trials in 646 report better hydration and elasticity after about three months. The same authors point to small studies and an unclear risk of bias. Our reading: they can accompany a plan, not replace a signal that reaches the dermis.
How we stimulate it in clinic
Each technology carries a different signal, to a different depth. So we start from what your skin is missing.
As with every technology that enters the clinic, the protocol is set by the medical team after an individual assessment. Technology matters, but knowing when and how to use it matters more.
Measure before promising
New collagen is built in weeks and shows in months, so it has to be measured. Before starting, the Aura 3D scan records the texture, fine lines and volumes of your face; at two or three months we repeat it on the same map and compare.
