How GOURI builds collagen — mechanism and injection design

The material in GOURI is polycaprolactone (PCL), long used in the collagen-biostimulator class. What makes GOURI different is not the material but the formulation.

No spheres means nothing that can clump, and a water carrier means it spreads naturally along the plane it is placed in. The difference between the two formulations is covered in the same polycaprolactone: how the liquid and microsphere forms differ.

There are two steps.

In the syringe it is a dispersion. An amphiphilic block copolymer sits stably dispersed in water as a colloid, which is why it looks like a clear liquid and passes smoothly through a fine needle — there are no particles in it.

In the dermis the dispersion resolves. The structure breaks down in the body, the polymer chains associate into a matrix structure, and the body reads that structure and begins the wound-healing sequence in which fibroblasts are activated and new collagen is produced.

This route is shared across the collagen-biostimulator class; the class as a whole is set out in what gets called a collagen booster.

This is the practical heart of GOURI. Because the material spreads, how many points it is divided across and which plane it enters decide the result far more than the total volume does.

• The plane decides the result. Too superficial and the surface can look uneven; too deep and the signal reaching the dermis is weaker. We aim for the deep dermis.
• Division decides the spread. Put it all in one place and only that place fills out while the area beside it stays empty. Dividing the points is what produces an even sheet.
• Plane first, points second. Once the plane is settled, the number of points follows from it. Reverse the order and the total is right but the distribution is not.

The injection design is set out in GOURI in Daegu — what spreading evenly actually means.

Because the mechanism is collagen formation, the change builds over time. What looks full immediately after the injection is the water that was placed plus ordinary swelling, and it settles within a day or two. That is not the result.

The full course over time is in GOURI — from the day of the injection to months later.

The same product is handled differently from clinic to clinic. These are our own standards, as we apply them.

We do not fix the number of sessions on a calendar in advance, for a simple reason: skin comes up at different rates in different people. If it has come up well by four weeks, we do not recommend another session.

A few things worth settling before the first session.

• There is no reversal injection. Polycaprolactone is not hyaluronic acid, so hyaluronidase does not dissolve it. That is exactly why we place conservatively at first and decide at four weeks whether to add — too little can be topped up, the other direction is harder.
• Sometimes the timing is worth moving. If a cold, dental work or a vaccination falls close by, we leave about two weeks either side. Overlapping them makes any reaction hard to attribute.
• Some situations we talk through first. If you are on immunosuppressive treatment or have an autoimmune condition, or are pregnant or breastfeeding, we will suggest a different approach instead. If there is inflammation or infection at the site, we wait for it to settle.
• Signs to call us about — pain that does not settle with time, an area turning white or dusky, or any change in vision. Please call rather than wait. These are not common, but seeing them early is what matters.

The full set of precautions is in GOURI — what to check before treatment.

The product itself is set out here. GOURI: liquid polycaprolactone as a collagen stimulator

Written and reviewed by Lee Chi-Hak, MD, director of Miso Clinic, Daegu. The treatment standards and injection design set out here are the ones we use in practice.