Skinboosters, polynucleotides, collagen inducers: what is the real difference?

Let's start with the most important question: what are we actually trying to treat?

Because that, ultimately, is where everything begins. With age, the face does not undergo a single transformation, but several at once. We may lose volume; the bone structure evolves; the fat compartments change; the ligaments shift. The skin, for its part, gradually becomes thinner, its collagen content diminishes, its elasticity changes, its hydration can decrease, and its texture sometimes becomes less even.

There is therefore no single injection capable of perfectly addressing all of these phenomena at the same time. And that is precisely why we have different products at our disposal.

First family: volumising fillers

Let's start with what everyone knows: hyaluronic acid. But here again, there is an enormous variety of different types. Some are designed to be very soft and pliable, others far more structural; some are injected superficially, others deeply.

When we use a hyaluronic acid filler, the primary goal is generally to restore volume, support a structure, modify certain contours, correct a depression, or harmonise certain proportions of the face — the cheekbones, the chin, the temples, the lips, or areas of volume loss. In this case, the product itself delivers part of the desired effect: we are physically adding something into a space where we wish to achieve a structural result. This is what is commonly referred to as a filler.

Second family: skin boosters

And this is where the confusion often begins, because some skin boosters also contain hyaluronic acid. So what is the difference from a filler? The objective. A skin booster is generally not used to rebuild a cheekbone or project a chin: it is designed first and foremost to improve hydration, suppleness, skin quality, certain fine lines, and the overall appearance of the skin.

We are therefore not primarily looking to fill, but to improve the quality of the tissue itself. Hyaluronic acid has an extraordinary capacity to interact with water and with the extracellular matrix environment; when injected according to certain formulations and protocols into the skin, it can improve its hydration and certain mechanical properties.

A very simple image to help understand: think of a sofa. A filler would be more like restoring its padding or structure, whereas a skin booster would be more like improving the quality and suppleness of its upholstery. These are not the same problems; we therefore do not necessarily use the same treatment.

Third family: collagen inducers

We now arrive at a very different family. Among the best-known products, we find in particular poly-L-lactic acid (PLLA) and calcium hydroxyapatite (CaHA). You may be more familiar with some of their brand names: Sculptra for certain PLLA-based products, Radiesse for calcium hydroxyapatite. Here, our goal changes: we want to trigger tissue remodelling and stimulate the production of new extracellular matrix, in particular collagen.

How does a collagen inducer work?

It is fascinating, because we are in reality using the body's own biological response. After injection, the product's particles interact with the tissue and a controlled inflammatory response appears; various immune cells, notably macrophages, take part in this reaction. This biological cascade then influences fibroblasts, which are extremely important: they are the ones that produce collagen, elastin, and various components of our extracellular matrix. The goal is therefore to gradually encourage the tissue to remodel itself — this is what we call neocollagenesis.

That is why the result is not immediate

This is something I explain a great deal to my patients. With certain fillers, you can look at your face in the mirror immediately after the injection and already observe a significant part of the result. With a true collagen inducer, time is part of the treatment: the product triggers a biological process, and then your body must gradually build new tissue, which takes weeks and then months. The result appears progressively.

And personally, this is precisely something I appreciate greatly about this approach: the face does not change abruptly; it is the quality and structure of the tissue that evolve little by little.

And now, let us turn to the much-talked-about polynucleotides

This is probably one of the most discussed treatments at the moment. They are called PN — polynucleotides. You will also frequently hear about PDRN — polydeoxyribonucleotides. These terms are sometimes used interchangeably in marketing, even though they do not refer to exactly the same molecular preparation; let us nonetheless retain the general principle.

What is a polynucleotide?

To understand, let us go back to biology. Our DNA is made up of units called nucleotides; when these nucleotides are assembled into chains, we obtain polynucleotides. The products used in aesthetic medicine therefore contain highly purified fragments of nucleotide polymers, historically derived in particular from DNA material sourced from fish such as salmon or trout.

And immediately, some patients say to me: 'Doctor, are you going to inject me with salmon DNA?' It is a very dramatic way to present it on social media, but a somewhat misleading one. We are obviously not transferring the genetic characteristics of a salmon into your skin: we are using purified nucleotide fragments for their biological and physicochemical properties.

But what do polynucleotides actually do?

We need to be precise, because one sometimes reads: 'polynucleotides manufacture collagen.' That is far too simplistic. PNs appear to act on several components of the tissue environment; they are studied in particular for their effects on fibroblast activity, the extracellular matrix, tissue hydration, certain inflammatory pathways, and tissue repair or regeneration.

The goal is therefore more about creating a biological environment that is conducive to an improvement in tissue quality. That is why I prefer to speak of biorevitalisation or biorestructuring, rather than simply presenting them as 'a new filler'.

Do polynucleotides add volume?

That is not their primary objective — and that is precisely one of their advantages. When I am treating thin, creased, dehydrated skin that has lost its elasticity, or skin whose quality I simply wish to improve, I am not necessarily looking to add volume: sometimes I simply want to improve the existing tissue. And polynucleotides can be interesting within this philosophy.

The perfect example: the eye contour

This is probably one of the areas that best illustrates this difference. A patient comes in and says: 'Doctor, I look tired.' But behind that phrase can lie several completely different problems. They may have a genuine hollow under the eye, and in certain situations a dermal filler may be considered. But they may also have extremely thin, slightly crinkled, dehydrated skin that has lost its elasticity — and in that case, filling is not necessarily the right answer.

We may then want to improve the quality of the skin without creating volume. And that is precisely one of the situations where polynucleotides have generated a great deal of interest.

Polynucleotides and skin boosters: what is the difference?

This is probably the most common source of confusion, as both can be used to improve skin quality. However, their biological rationale is not exactly the same. A hyaluronic acid-based skin booster acts significantly on hydration, on the viscoelastic properties of the tissue, and on the extracellular matrix environment. Polynucleotides, on the other hand, are used more within a logic of biorevitalisation, tissue repair, modulation of the cellular environment, and progressive improvement of skin quality.

The boundaries are obviously not completely watertight: both can improve certain shared parameters. But they do not follow exactly the same biological pathways.

And are polynucleotides collagen inducers?

This is where I want to make an important distinction: not in the same sense as PLLA or calcium hydroxyapatite. Yes, polynucleotides can influence fibroblasts, and some studies report improvements in parameters related to dermal quality. But I would not automatically place polynucleotides, Sculptra, and Radiesse in the same category.

Particulate inducers such as PLLA or CaHA trigger a tissue response that is particularly oriented toward lasting neocollagenesis and extracellular matrix remodeling. Polynucleotides, on the other hand, act more on the biological environment of the tissue and its quality. That is an important distinction.

So why does everyone call everything a 'biostimulator'?

Because the term is appealing. 'Biostimulation' immediately gives the impression that we are asking our body to work naturally — and that is partly true. But today, this word has become so broad that it sometimes ends up meaning very little. A product may hydrate, modify the extracellular matrix, stimulate fibroblasts, trigger neocollagenesis, or combine several of these mechanisms — and yet all of them will sometimes be sold under the same word 'biostimulation.' That is why I always prefer to ask: what do we want to achieve biologically?

Do polynucleotides really work?

We now have some interesting clinical data. Studies have found improvements relating to certain wrinkles, texture, elasticity, hydration, and patient satisfaction. But I also want to be honest about the current state of the science: we have far less robust data on polynucleotides than on some treatments that have been in use for much longer.

A recent systematic review identified only nine studies involving 219 patients. The results were promising, but the overall quality of the studies was low to moderate, and the protocols were highly variable. This means: promising, yes; interesting, yes; miraculous, no. And above all, we still need better studies.

An important difference from established collagen inducers

For PLLA and calcium hydroxyapatite, we now have a much more substantial body of literature on neocollagenesis, histological changes, matrix remodeling, and the duration of results. This does not mean that polynucleotides are less interesting: it means they do not necessarily address the same objective, and that we must respect the level of evidence available for each technology.

So, which one should you choose?

That is probably the wrong question. The right one is not 'which is the best product?', but 'what does my skin need us to correct?'

If I have lost volume, we can consider a filler, because we want to restore structure. If my skin is mainly lacking hydration and suppleness, we can discuss a skinbooster, because we are looking to improve the quality and hydration of the tissue. If I want to trigger true collagen induction, we can consider a PLLA, a calcium hydroxyapatite, or other inducers depending on the indication, because the objective is then neocollagenesis and remodelling. And if I wish to improve thin, fragile, or damaged skin without necessarily creating volume, polynucleotides can be an interesting option in certain indications, working more on the biological quality of the tissue.

And sometimes, the best strategy is to combine

Because a face never ages in just one way. You may simultaneously present volume loss, a decrease in collagen, dehydrated skin, dynamic wrinkles, sun damage, and uneven texture. Why insist on treating all of this with the same syringe?

This is precisely where intelligent aesthetic medicine begins. We can combine, within a considered strategy and at different moments, botulinum toxin, hyaluronic acid, collagen inducers, polynucleotides, lasers, photobiomodulation, peels, or other treatments — not to multiply procedures, but because each tool must address a specific problem.

And this is where the consultation becomes essential

I sometimes see patients come in saying: 'Doctor, I want polynucleotides.' My first question is not 'how many syringes?', but 'why?' What is bothering you: your skin, your volume, your eye contour, your wrinkles, your sagging, your texture? Because perhaps polynucleotides are perfectly indicated — but perhaps your problem also requires something completely different. We must not adapt the patient to the product: we must choose the product based on the patient.

The simplest table to understand

Un filler a pour objectif principal de restaurer ou de modifier un volume et une structure. Un skinbooster vise surtout à améliorer l'hydratation, la souplesse et certaines caractéristiques de la qualité cutanée. Les polynucléotides cherchent à biorevitaliser et à améliorer progressivement l'environnement et la qualité du tissu, sans rechercher principalement un effet volumateur. Un inducteur collagénique, enfin, a pour objectif de déclencher une néocollagénèse et un remodelage tissulaire progressifs et durables.

None is 'better'

This is probably the most important message in this article. A hammer is not better than a screwdriver: it simply addresses a different problem. In aesthetic medicine, it is exactly the same. The best dermal filler in the world will be a poor treatment if your problem is not a lack of volume; the best skinbooster will not replace a true collagen inducer when the goal is significant structural biostimulation; and injecting a collagen inducer is not automatically the best solution for extremely thin skin around the eyes. The indication matters more than the trend.

Beware of trends

Aesthetic medicine unfortunately also operates on trends. Yesterday, everyone wanted hyaluronic acid; today, everyone wants polynucleotides; tomorrow, it will probably be a new molecule. But your skin does not know Instagram: it knows biology. And our role as physicians is precisely to understand that biology before choosing a treatment.

What I want you to take away

If someone offers you a 'biostimulation' treatment, simply ask this question: with what? Hyaluronic acid? Polynucleotides? PLLA? Calcium hydroxyapatite? Because behind one and the same word can hide products whose composition, mechanism, injection depth, objective, speed of action, and duration of results are completely different.

I am Dr Florian Vallecillo. And if I had to leave you with a single idea today, it would be this: in modern aesthetic medicine, we must no longer simply ask 'what are we injecting?' but 'what are we trying to do to the tissue?' Filling, hydrating, biorevitalising, or inducing collagen: these are four different objectives. And it is only once we have answered that question that we can intelligently choose between a filler, a skinbooster, polynucleotides, or a collagen inducer. Because a successful aesthetic treatment does not begin with the trendy product: it begins with a diagnosis.