Why put four types of hyaluronic acid in one serum? Because hyaluronic acid isn't one-size-fits-all. Molecule size changes how it behaves on and in the skin, and the research shows that different sizes do different jobs.
Here's the science behind molecular weight, and why we built a serum around four forms instead of one.
What does hyaluronic acid do?
Hyaluronic acid (HA) is a water-binding molecule your skin makes naturally. In skincare, it's a humectant: it draws water in and holds it, leaving skin smoother, plumper and more supple-looking.
Why molecular weight matters
HA molecules come in different sizes, measured by molecular weight. Larger molecules form a water-binding film on the surface, so skin feels cushioned and smooth immediately. Smaller molecules travel further into the skin's outer layers.
A 2016 Raman spectroscopy study tracked HA of different sizes through human skin samples and found that lower-molecular-weight HA (20 to 300 kDa) passed through the outer skin barrier more readily than larger HA (1,000 to 1,400 kDa).
Different sizes, different depths. That's the foundation of a multi-weight formula.
What human trials show
A randomized study in the Journal of Drugs in Dermatology enrolled 76 women aged 30 to 60. Each used a 0.1% HA cream of one of five molecular weights around one eye, and a control cream around the other, for 60 days.
Every one of the five HA weights improved measured hydration and elasticity compared with the control. The 50 kDa and 130 kDa creams went further, also improving measurements of wrinkle depth.
A 2024 double-blind randomized trial compared low- and high-molecular-weight HA lotions in adults with dry skin. After four weeks, the low-molecular-weight formula produced the highest skin-hydration measurements.
And a 2022 review of topical HA brings together the research on hydration and the look of smoother skin.
Why four forms work together
If every size of HA hydrates, and different sizes work at different levels, the logical next step is to combine them. That's exactly what we did. Each of our four forms brings something different:
- Sodium hyaluronate crosspolymer, a networked form that cushions the surface and holds moisture over time.
- Sodium hyaluronate, the classic form, for an immediate plumping, smoothing feel.
- Sodium acetylated hyaluronate, a modified form designed to bind well to the skin's surface.
- Hydrolyzed sodium hyaluronate, broken into smaller fragments to reach further into the skin's outer layers.
Together they deliver hydration you can see and feel, from the surface down.
Meet the 4-Type Hyaluronic Acid Serum
Our 4-Type Hyaluronic Acid Serum combines all four forms with glycerin and propanediol in a lightweight, fast-absorbing serum. Skin feels supple instantly and looks smoother and plumper with every use.
Seal it in with our Peptide Barrier Moisturizer: the serum draws water in, the cream locks it there. That's the complete hydration routine.
How to use a hyaluronic acid serum
- Cleanse, then leave skin slightly damp.
- Apply a few drops of serum and press it into the skin.
- Moisturize straight away to lock hydration in. The American Academy of Dermatology recommends applying moisturizer to damp skin.
- Morning: finish with broad-spectrum SPF 30 or higher.
Not sure whether your skin is dry or dehydrated? Read our guide to dry versus dehydrated skin.
Frequently asked questions
Does hyaluronic acid pull moisture out of skin in dry weather?
Not when you use it right. Apply it to damp skin and follow with a moisturizer, and the water it draws in stays where you want it.
Is smaller hyaluronic acid better?
Each size has its own job. Smaller molecules reach further into the skin's outer layers; larger ones cushion and protect the surface. That's why we use both.
Can I use it morning and night?
Yes. It layers under every other Domi formula, including vitamin C in the morning and retinol at night.
Is it suitable for oily skin?
Yes. Its lightweight, water-based texture hydrates without adding shine.
The Domi Effect: hydration from the surface down
Four forms of hyaluronic acid, each doing its own job, all in one step. Hydration plumps the surface. A plumper surface reflects light more evenly. Every step after it works on better-prepared skin.