If you've spent any time browsing the skincare aisle — or the skincare side of the internet — you'll have seen hyaluronic acid (HA) listed on what feels like every other serum. It's one of the most researched, most recommended and most consistently effective ingredients in modern skincare. But what actually is it, what does it do, and how do you know which form you're getting?
Here's everything you need to know, plus a rundown of the REFORM Skincare products that contain it.
What Is Hyaluronic Acid?
Hyaluronic acid is a polysaccharide — a type of sugar molecule — that occurs naturally throughout the human body. It's found in your skin, your eyes and your joints, where it plays a structural and cushioning role. Roughly half of the body's hyaluronic acid sits in the skin.
Its headline talent is water binding. A single HA molecule can hold up to a thousand times its own weight in water, which makes it one of nature's most effective humectants: an ingredient that attracts water and holds it in place. In the skin, that translates to that plump, quenched, "bouncy" quality you associate with well-hydrated skin.
The catch is that levels decline with age. Hyaluronic acid in the skin starts to drop from around the age of 25, and as it does, skin loses volume, moisture and elasticity. That's why topical HA has become such a mainstay of anti-ageing routines — you're topping up something your skin is steadily running out of.
Is it an "acid" in the scary sense? No. Despite the name, hyaluronic acid is not an exfoliating acid like glycolic or salicylic. It won't resurface, sting or peel your skin. The "acid" is simply a chemical classification.
Hyaluronic Acid vs Hydrolyzed Hyaluronic Acid
This is where things get interesting, and where a lot of products quietly differ from one another.
Hyaluronic acid comes in many different molecular weights — essentially, different chain lengths. A long, heavy chain (high molecular weight) sits on the surface of the skin. A short, light chain (low molecular weight) can travel further in.
Hydrolyzed hyaluronic acid is HA that has been deliberately broken down through hydrolysis — a process that splits the long chains into much shorter fragments. The result is a very low molecular weight form, and it behaves quite differently:
- Standard hyaluronic acid primarily hydrates the upper layers. It forms a moisture-binding film on the surface that cushions, smooths and softens.
- Hydrolyzed hyaluronic acid penetrates more deeply, reaching further into the epidermis to hydrate from within. Research published on skin penetration has shown that low molecular weight HA passes through the stratum corneum, while high molecular weight HA does not.
Because of this, the best formulas often combine both: surface hydration for immediate plumpness, and deeper hydration for longer-term benefit. Hydrolyzed HA tends to be particularly useful for oily or combination skin, since it delivers moisture without the heaviness of a richer formulation.
What Are the Benefits for Skin?
The evidence base for topical hyaluronic acid is genuinely strong — it's not marketing fluff. A widely cited review of clinical evidence, Benefits of topical hyaluronic acid for skin quality and signs of skin aging, concluded that HA-based cosmeceuticals are a well-tolerated and effective route to improving hydration and rejuvenation. The main benefits are:
Deep, lasting hydration. This is the core benefit and the foundation for everything else. HA draws water into the skin and helps hold it there. Studies have recorded measurable improvements in skin hydration within two to eight weeks of consistent use.
Plumper, smoother texture. Well-hydrated skin looks fuller and reflects light more evenly, so fine lines appear softened. It's not filler — nothing topical is — but the visual effect of a plumped-up skin surface is real.
A more resilient skin barrier. A well-hydrated stratum corneum defends itself better against environmental stressors, pollution and moisture loss. HA supports the skin's own moisture balance rather than just adding a temporary slick of water.
Improved firmness and elasticity. Hyaluronic acid is a natural component of the extracellular matrix, the scaffolding that gives skin its structure. Replenishing it topically supports elasticity and suppleness over time.
Better tone and evenness. Some studies note improvements in skin tone after four to eight weeks, and increased epidermal thickness after twelve weeks of regular use.
Soothing and calming. Because it's a naturally occurring molecule in the body, HA is exceptionally well tolerated. It's rare to react to it, which makes it one of the few genuinely universal skincare ingredients — suitable for sensitive, reactive and compromised skin.
An important practical point: HA works best as part of a team. Used in isolation, it can actually draw moisture from deeper layers if the surrounding air is very dry, leaving skin feeling tight. Applying it to slightly damp skin, and sealing it in with a moisturiser, is how you get the most from it.
REFORM Skincare Products with Hyaluronic Acid
REFORM Skincare is a doctor-formulated cosmeceutical range built around proven actives at meaningful concentrations, and hyaluronic acid runs through several formulas in the line — in both its standard and hydrolyzed forms.
HYAL • Vitamin C + E Serum
The brand's flagship, and an excellent example of HA layered into a broader antioxidant formula. It combines 0.1% hyaluronic acid with 15% L-ascorbic acid (vitamin C), 1% vitamin E, panthenol and ferulic acid. The HA works as the hydrating and plumping counterweight to the brightening, free-radical-fighting actives. It's particularly suited to ageing and menopausal skin, where both hydration and antioxidant support are priorities.
Vitamin B5 Gel
A fast-absorbing, oil-free gel built on a simple, effective pairing: 0.1% hyaluronic acid and 1% vitamin B5 (panthenol). The HA attracts and retains moisture and helps plump the skin; the panthenol soothes irritation, supports the skin's repair process and reinforces the barrier. It's a strong choice for dry, sensitive or compromised skin, and light enough not to clog pores.
Intensive Moisturiser
Here hyaluronic acid appears in its hydrolyzed form, paired with glycerin. Where a surface-level HA gives you instant plumpness, hydrolyzed HA goes deeper — providing hydration that plumps the skin and improves elasticity for a smoother, more radiant finish. This is the product to reach for if you want HA working at more than one level of the skin.
Hyaluronic Acid Serum
A dedicated HA serum that focuses the ingredient's core benefits: supporting the skin's natural firmness and elasticity, softening the appearance of fine lines and wrinkles, and plumping the skin with moisture. If hydration is your primary goal rather than a secondary benefit, this is the most direct route.
Glycolic Acid Foaming Cleanser
Worth knowing about even though it's a cleanser: this is a resurfacing step rather than a hyaluronic acid product in the hydrating sense, and makes a sensible pairing with the serums and moisturisers above — exfoliating to clear the surface, followed by HA to replenish what's been removed.
How to Get the Most from Hyaluronic Acid
A few practical notes to make it work harder:
- Apply to damp skin. HA needs water to bind. Mist or pat your face with water first.
- Layer, don't isolate. Follow with a moisturiser to seal the hydration in — especially important in centrally heated homes and during the colder UK months.
- Order matters. Thinnest to thickest: cleanser, HA serum or gel, then moisturiser. Vitamin C formulas such as HYAL • Vitamin C + E in the morning, hydrating layers throughout.
- Be consistent. Hydration benefits show up within a couple of weeks, but structural improvements in elasticity and tone take longer — think two to three months of daily use.
- Look for more than one molecular weight. A formula with both standard and hydrolyzed HA hydrates at multiple depths, which is why pairing a hydrating gel with the Intensive Moisturiser makes sense.
The Bottom Line
Hyaluronic acid is one of the few skincare ingredients that is both genuinely effective and universally well tolerated. Its job is simple and essential: it holds water in your skin, and the more of that you do, the plumper, smoother and more resilient your skin looks. Hydrolyzed hyaluronic acid takes that a step further by reaching deeper layers, where it supports hydration and elasticity rather than just the surface.
In the REFORM Skincare range, that shows up across the HYAL • Vitamin C + E Serum, the Vitamin B5 Gel, the Intensive Moisturiser (hydrolyzed) and the dedicated Hyaluronic Acid Serum — several routes to the same core benefit, depending on whether hydration is your headline goal or a supporting player in a broader routine.
This article is for general information and is not a substitute for advice from a qualified dermatologist or healthcare professional.
