Same material, different product

This page is written for general readers. It does not recommend any procedure, product or clinic, and it carries no efficacy, duration or price information. Decisions about treatment belong with a qualified clinician who has examined you.

Question

If the material is the same, why do products differ?

The same material name does not make the same product. In the literature the variables that actually separate them narrow to a few: for particles, size and its distribution; for gels, the degree of crosslinking; for biologically sourced materials, the source and the purification; and what the material is suspended in. Whether a result from one product can be carried to another depends on whether these match.

The material name is the start, not the end

Knowing the material matters — it is why the other pages here keep telling you to ask for it. But knowing the material is not knowing the product. Under one name there are variables that separate products from each other.

For particles — size and distribution

Particulate materials list size as a specification. In the literature, though, size is not a specification but a variable, because tissue has been reported to handle particles differently by size band.

What most often goes missing here is the distribution. The figure in product literature is usually a mean or a representative value, and how tightly the particles cluster around it is not given alongside. With the same mean but a wide spread, the population tissue meets is a different one.

For gels — the degree of crosslinking

Hyaluronic acid on its own clears quickly. Linked chemically into a network, it becomes a gel that resists breakdown. Most of the properties used to describe a filler come from that network rather than from the molecule.

So two products made from the same raw material can behave differently. The crosslinking agent and the degree of crosslinking differ between products, and are not always disclosed.

For biologically sourced materials — source and purification

Materials obtained from animals or marine organisms differ by species, by extraction method and by how far they were purified. The literature does not always state these.

When the name denotes a method rather than a substance

This is the case to be most careful with. Some names denote a chemical; others denote how something was made. For the second kind, which cells, under what culture conditions, isolated by which method, all differ between companies.

Here the sentence “a study of that name reported this result” attaches, on its own, to no product at all. Three variables have to match first — and frequently they are not disclosed.

Not being able to check is also information

Where these variables are absent from product literature, there is no way to verify them. That absence is itself worth knowing. The fewer specifications disclosed, the weaker the grounds for carrying another product’s results across.

What to check first

When size is stated, is it only a mean, or is the distribution given too?

Two products with the same mean can present entirely different populations of particle if the distribution is wide. The literature reports that tissue handling differs by size band, so a wide distribution spans several bands at once.
What is it suspended in?

The same particle has been observed to distribute differently in tissue depending on the carrier. A specification sheet lists one particle; what tissue meets is the particle and its carrier together.
Did this study use this product?

It may have used a different product carrying the same material name. A shared material name is not by itself grounds for carrying the result across.
Is this name a substance, or a method of making?

Some names denote a chemical; others denote how something was produced. The second kind can differ in contents between companies, which makes carrying a result from one product to another considerably harder.

What this page does not say

This page does not confirm the specifications of any product and does not compare products with each other. It explains only the variables that make products differ. These variables are often not disclosed in product literature, and where they are not, verification is impossible — which is itself part of what this page says.