HumectantDraws in waterIn every formula

Glycerin

Glycerin · INCI Glycerin

Glycerin is the ingredient nobody puts on the front of a bottle. It is cheap, it has been used for well over a century, and it works better than almost anything that has come along since. We are rather fond of it.

The cheapest ingredient in the bottle and among the best evidenced in all of skincare. Those two things are not a coincidence.

Glycerin, the humectant that draws water into the skin in every formula.

What it is

Glycerin is a humectant, which means it attracts water and holds on to it. Applied to the skin, it draws moisture up from the layers beneath and in from the air around you, and keeps it in the outer layer, which is where dryness is actually felt. That is the whole mechanism, and it is about as well demonstrated as anything in cosmetic science.

What makes it more than a comfort ingredient is that water in the outer skin is not just about how skin feels. The enzymes that let old cells detach need moisture to work. So do the processes that keep the barrier in order. A properly hydrated surface is a surface that can look after itself, and glycerin is the most dependable way we know of getting it there.

It works particularly well alongside oils, which is convenient, because our formulas are mostly oils. The glycerin draws the water in; the oils slow its escape. One without the other is half a job.

What it does in our formulas

Two things, both about water, and both about as well established as skincare gets.

It pulls water into the skin

Glycerin is a humectant: it attracts water and holds on to it. Spread on the skin, it draws moisture up from the deeper layers and in from the air, and keeps it in the outer layer where dryness is felt. This is one of the most thoroughly demonstrated effects in cosmetic science, and it is why glycerin is in nearly every moisturiser ever made.

Well characterised

It helps the skin work properly

Water in the outer layer is not just about comfort. The enzymes that let dead cells detach and the processes that keep the barrier in order all need moisture to function. The research shows that keeping the surface properly hydrated helps the skin do its own housekeeping, and glycerin is the most reliable way we know to do that.

Well characterised

What the research does not show

Glycerin's problem is not that it is over-claimed. It is that it is quietly disparaged, usually by people with something more expensive to sell.

Marketed as It is a cheap filler, and a serious product would use something fancier

This is the claim worth arguing with, and it is usually made by people selling something fancier. Glycerin is inexpensive because it is easy to make, not because it is ineffective. It is one of the most rigorously demonstrated ingredients in the whole field, and a moisturiser that left it out to make room for a more marketable humectant would be a worse moisturiser.

Marketed as In dry weather it steals water from your skin

You will see this repeated confidently. It comes from the fact that a humectant, used neat in very dry air, can in principle pull water from the skin rather than into it. In an actual moisturiser, sitting in a cream alongside oils that hold that water in, it does not happen. We would not build every formula around it if it did.

So we use it, generously, in every formula, and we are not going to apologise for it or bury it in the middle of the list. It is one of the few ingredients in skincare that genuinely earns its reputation.

On the label and in the range

Glycerin appears in every one of our formulations, high in the ingredient list, because it does real work and needs to be present in real quantity to do it. If you have been taught to read a high-ranking cheap ingredient as a sign of cost-cutting, this is the one to unlearn that on. The exact percentage is published on each product page.

Is it suitable for me?

Glycerin has one of the longest and cleanest safety records of any cosmetic ingredient, is well tolerated on even very sensitive skin, and carries no restrictions under UK or EU cosmetic law. Ours is plant-derived, so it suits a vegan routine. Glycerin can be made from animal fat or from petroleum, and it is worth knowing that, and worth asking about anywhere it is not stated.

Vegan-friendlySensitive-skin suitableNo known safety concerns

Glycerin is among the gentlest ingredients in cosmetic use. 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.

Fluhr JW, Darlenski R, Surber C. Glycerol and the skin: holistic approach to its origin and functions. Br J Dermatol 2008;159(1):23-34. →
Milani M, Sparavigna A. The 24-hour skin hydration and barrier function effects of a hyaluronic 1%, glycerin 5%, and Centella asiatica stem cells extract moisturizing fluid. Clin Cosmet Investig Dermatol 2017;10:311-315. →
Man MQ, Elias PM. Stratum corneum hydration regulates key epidermal function and serves as an indicator and contributor to other conditions. J Eur Acad Dermatol Venereol 2019;33(1):15-16. →

Found in every Biotaderm formulation Shop the range