Glycerin: the unfashionable ingredient derms swear by

If you were to judge skincare purely by marketing, you’d be forgiven for thinking that hydration begins and ends with hyaluronic acid. From serums and injectables to sheet masks, HA has been positioned as the gold standard for plump and dewy skin. However, sitting in the background of almost every moisturiser, cleanser and serum is a far less glamorous ingredient: glycerin.

It’s not new or trendy, but as Dr Hazel Parkinson, GP, Aesthetic Doctor & Skin Health Specialist says, “Glycerin is one of the most reliable humectants we have, helping to attract and retain water within the skin, which is fundamental for maintaining barrier function and overall skin health.”

So why has glycerin been overlooked, and is it finally having a moment?

What glycerin is and what it does (and why it matters)

Glycerin, also known as glycerol, is a colourless, odourless sugar alcohol first identified in 1779 by a Swedish scientist, who isolated the substance while making soap from olive oil. Non-toxic and naturally viscous in texture, it has since become a widely used ingredient in everything from food and medications to skincare.

Mainly used as a humectant—an ingredient that draws water into the skin—glycerin has been shown in studies to penetrate the skin barrier and remain within the skin for continuous hydration over several days. Effective and well-tolerated, it doesn’t irritate sensitive skin and is comfortable for both dry and oily skins.

In terms of the barrier function, well-hydrated skin isn’t just about adding moisture, it’s about preventing water loss in the first place. Glycerin has been shown to improve both the hydration levels and barrier function over time, not immediately after application.

Glycerin vs hyaluronic acid: what’s the difference?

Both glycerin and hyaluronic acid are humectants, meaning they attract water, although they behave slightly differently on the skin.

“Higher molecular weight hyaluronic acid tends to sit more superficially and gives temporary surface hydration and plumping,” says Dr Parkinson, “whereas glycerin works very effectively within the upper layers of the skin to improve water balance.”

There are also textural considerations. Glycerin can feel slightly sticky in higher concentrations, whereas hyaluronic acid is lighter and creates that immediate plumping effect—likely to be one of the reasons why it’s become so high profile.

Why it’s back in the conversation

“Glycerin may not be the most trend-led ingredient, but it is one of the most clinically reliable and multifunctional hydrators we have in topical skincare,” says Dr Parkinson.

In part, this comes down to a broader shift in skincare. After a decade of over-exfoliation and over-treatment, the emphasis has moved away from quick-fix actives and towards barrier repair, resilience and overall skin health.

Versatility is another advantage to glycerin. “It integrates well into cleansers, serums, moisturisers, and barrier creams without significantly increasing irritation potential or texture”, says Dr Parkinson, “It also improves the efficacy and tolerability of other ingredients by reducing trans epidermal water loss and improving overall skin hydration.”

Further, it works well across a wide range of skin types and concerns, particularly dry or dehydrated, sensitive or reactive skin as well as skin with a compromised barrier, whether from over-exfoliation or post treatment recovery. Acne-prone skin can also benefit, as glycerin helps hydrate without adding heaviness or excess oil.

That said, it’s not perfect for everyone. In higher concentrations it can feel slightly sticky, which for very oily skin types isn’t always preferable.

How glycerin is used in products

One of glycerin’s strengths is that it works across almost every category of skincare product. “It’s rarely the headline ingredient, but it’s often doing a lot of the heavy lifting within a formulation,” says Dr Parkinson. “Because it’s so compatible with other ingredients, it helps support both efficacy and tolerability.”

Brands including HydroPeptide incorporate glycerin across multiple formulations, particularly those focused on hydration and barrier support. It’s also frequently paired with ingredients such as ceramides, squalane and hyaluronic acid to create more balanced hydration rather than simply delivering a temporary “plumping” effect.

Unlike some trend-led ingredients, glycerin also performs consistently across different skin types and environments, one reason formulators continue to rely on it despite the constant churn of new skincare actives.

So, have we been overlooking it?

In many ways, yes. Glycerin doesn’t have the glamour of newer actives or the instant gratification of hyaluronic acid. But that may be precisely why it’s worth paying attention to. It offers dependable, long-term hydration, rather than simply delivering a temporary “plumping” effect. It is one of the most clinically reliable and multifunctional hydrators we have in topical skincare.