EmollientPreservative boosterIn every formula

Glyceryl Caprylate

Glyceryl Caprylate · INCI Glyceryl Caprylate

This ingredient does two useful things and raises one awkward question, and since the question is about the thing this whole brand is built on, it would be cowardly to leave it out.

It softens the skin, and it helps keep the product safe. The second job is one a microbiome brand has to think carefully about, and we would rather do that in public.

Glyceryl caprylate, the plant-derived emollient that also helps preserve the formula.

What it is

Glyceryl caprylate is made by joining glycerin to caprylic acid, both from plant oils. On the skin it is an emollient: it softens, and it helps the formula spread and feel the way it does. That alone would earn it a place.

It also makes life difficult for microbes, by disrupting their membranes. It could not preserve a cream by itself, but alongside the gluconolactone and the sodium benzoate it means the whole preservative system can be gentler than it would otherwise need to be. That is a genuine benefit, and it is part of why these formulas suit reactive skin.

And now the awkward part. A preservative does not stop working when you take the cream out of the jar. It goes onto your skin, and it stays active there for a while, and your skin is where your microbiome lives. We are a brand built on supporting that microbiome. It would be strange not to ask what our own preservatives are doing to it.

The honest answer is that we do not fully know. The research shows this matters: some preservative systems hold back the troublesome species while leaving the helpful ones alone, and others suppress the helpful ones as well. We chose about the gentlest system available to us, and we chose it deliberately. But nobody has tested our particular combination on a human microbiome, and until somebody does, we are not going to tell you it is fine. We will tell you we thought about it, we made the most careful choice we could, and the question remains open.

What it does in our formulas

Two things it does, and one thing we are still thinking about.

It softens the skin

A genuine emollient. It smooths the surface, improves how the formula spreads, and is part of why a cream feels like a cream rather than a paste. This is not a consolation prize; it is a real function and it is why we would want it here even if it did nothing else.

Well characterised

It helps keep the product safe

Glyceryl caprylate disturbs the membranes of bacteria and yeasts, which makes life difficult for anything trying to grow in the pot. It could not preserve a cream alone. Working with the gluconolactone and sodium benzoate, it lets the whole system be gentler than it would otherwise need to be, and a gentler preservative system is one of the reasons this range suits reactive skin.

Well characterised

What the research does not show

Two claims get made around ingredients like this one. The first is dishonest. The second is one we would love to make and will not.

Marketed as A natural preservative, so the product is preservative-free

This is the sleight of hand, and it is worth naming. Ingredients like this one are legitimately emollients, so they get listed as emollients, and then quietly relied on to keep the product safe. That lets a brand say preservative-free while being nothing of the sort. We use it partly as a preservative. We would rather tell you that than hide behind the word emollient.

Marketed as It is microbiome-friendly

We would like to be able to say this, and we cannot. Here is the difficulty, and it is ours as much as anyone's. A preservative does not switch off when the cream leaves the pot. It stays on your skin, where your microbes live. The research shows that some preservative systems hold back the difficult species while leaving the helpful ones alone, and that others knock back the helpful ones too. Our system was chosen to be as gentle as one can be, and nobody has tested this particular combination on a human microbiome. Anyone who tells you their preservative is microbiome-friendly is either quoting a study of a different system, or guessing. We are not going to do either.

What we are left with is an emollient that softens your skin, and a preservative that helps keep the product from going off, chosen to be as gentle as we could manage, with an honest question mark over the thing we care most about. That is where the evidence leaves us, so that is where we are going to stand.

On the label and in the range

Glyceryl caprylate appears in every one of our formulations, toward the end of the ingredient list, at a low level. Read it alongside the gluconolactone and the sodium benzoate: those three are the preservative system, and none of them does the job alone. All three are on the label, all three have a page here, and none of them is hiding.

Is it suitable for me?

Glyceryl caprylate is well tolerated, suits a vegan routine, and carries no restrictions under UK or EU cosmetic law. It is one of the gentler ways to help preserve a cosmetic, which is why it is in the range: the alternative is a harsher preservative at a higher level, and we would rather not.

Vegan-friendlySensitive-skin suitableNo known safety concerns

As with anything new, if your skin reacts easily it is worth patch testing first.

The research behind this page

We review the published literature. We do not conduct the studies below.

Pinto D, Ciardiello T, Franzoni M, Pasini F, Giuliani G, Rinaldi F. Effect of commonly used cosmetic preservatives on skin resident microflora dynamics. Sci Rep 2021;11:8695. (Industry-funded; peer-reviewed. Establishes that preservatives remain active on skin and shift resident flora.) →
Cosmetic Ingredient Review Expert Panel. Safety Assessment of Glyceryl Monoesters as Used in Cosmetics. Int J Toxicol. →
Fischer CL, Drake DR, Dawson DV, et al. Antibacterial activity of sphingoid bases and fatty acids against Gram-positive and Gram-negative bacteria. Antimicrob Agents Chemother 2012;56(3):1157-1161. →

Found in every Biotaderm formulation Shop the range