Hyaluronic acid is a water-holding sugar molecule that skin makes naturally. In serums and creams, often listed as sodium hyaluronate, it holds water in the surface layer so skin looks plumper and fine dryness lines soften. Its size matters: smaller forms pass the outer layer, while larger ones stay on top.
- Helps with
- dehydrated skin, fine dryness lines, dull skin, tightness
- Evidence
- Moderate. One controlled 76-person trial plus lab penetration work; the main effect is hydration rather than repair.
- Typical strength
- 0.1% in the 60-day eye-area trial cited here
- Works well with
- moisturizer, glycerin, ceramides
What does hyaluronic acid do for skin?
Hyaluronic acid is about water. Think of skin that looks fine in the morning but by afternoon shows tiny crisscross lines under the eyes, feels tight around the mouth and looks a little flat. That is dehydration, and hyaluronic acid is used to hold water in the surface so skin looks smoother and plumper.
Skin already makes it. A review on skin ageing calls it central to skin moisture: “The key molecule involved in skin moisture is hyaluronic acid (HA) that has unique capacity in retaining water.” Daily wear and ageing both reduce how much water skin holds, which is why it is added to products.
Does the size of hyaluronic acid matter?
Yes. Hyaluronic acid comes in different molecule sizes. In a lab study on human skin, smaller forms (20 to 300 kDa, a unit of molecule size) passed through the outer layer, while large forms (1,000 to 1,400 kDa) did not get in.
That matched a 60-day trial in 76 women aged 30 to 60. Each used a 0.1% hyaluronic acid cream around one eye and a plain cream around the other, twice a day. All five sizes tested, from 50 to 2,000 kDa, improved hydration and elasticity. Only the two smallest sizes, 50 and 130 kDa, also made wrinkles measurably shallower.
Does hyaluronic acid dry out skin?
It is a common worry, especially in dry air. We look at what the evidence does and does not show in does hyaluronic acid dry out skin?
How long until you notice a difference?
In the eye-area trial, hydration and elasticity were measured at 30 and 60 days, and the wrinkle changes were seen at 60 days.
How do you use hyaluronic acid?
After cleansing and before moisturizer, morning or night. A moisturizer on top helps keep the water in; see what order to put skincare on.
Who should be careful with hyaluronic acid?
Skin makes this molecule itself, but a serum’s other ingredients can still irritate. Patch test if your skin reacts easily.
- Papakonstantinou E, Roth M, Karakiulakis G. Hyaluronic acid: a key molecule in skin aging. Dermatoendocrinol. 2012;4(3):253-8.
- Pavicic T, et al. Efficacy of cream-based novel formulations of hyaluronic acid of different molecular weights in anti-wrinkle treatment. J Drugs Dermatol. 2011;10(9):990-1000.
- Essendoubi M, et al. Human skin penetration of hyaluronic acid of different molecular weights as probed by Raman spectroscopy. Skin Res Technol. 2016;22(1):55-62.
Editorial content, not medical advice.