# Hyaluronic acid

> Source: https://thecastindex.com/beauty/ingredients/hyaluronic-acid — updated 2026-09-25

Hyaluronic acid is a humectant: it attracts and holds water, helping skin feel and look more hydrated and plump. The body makes it naturally, and cosmetic formulas often combine several molecular sizes. It suits almost every skin type and works best under a moisturiser that seals hydration in.

- Also on labels as: Sodium hyaluronate, Hyaluronan, HA
- Type: Humectant

## What it does

- Draws water into the upper layers of skin for a hydrated, plumper look
- Gives serums and tints a light, non-greasy slip
- Supports comfort in dry or dehydrated skin

## Who it suits

All skin types, including oily skin that feels tight or dehydrated.

## How to use it

1. Apply to slightly damp skin after cleansing
2. Follow with a moisturiser to reduce water loss, especially in dry air
3. Use morning and evening

## Take care

- Rarely irritating; reactions are more often to other ingredients in the formula
- In very dry environments, always layer a moisturiser on top

## What it pairs with

Pairs with almost everything — niacinamide, ceramides, retinoids and vitamin C formulas often include it.

## Products in the catalogue that list it

- [The Ordinary Hyaluronic Acid 2% + B5 (with Ceramides)](https://thecastindex.com/beauty/the-ordinary-hyaluronic-acid-2-b5-ceramides)
- [CeraVe Hydrating Facial Cleanser](https://thecastindex.com/beauty/cerave-hydrating-facial-cleanser)
- [CeraVe Moisturising Lotion](https://thecastindex.com/beauty/cerave-moisturising-lotion)
- [COSRX Advanced Snail 96 Mucin Power Essence](https://thecastindex.com/beauty/cosrx-advanced-snail-96-mucin-power-essence)
- [Milk Makeup Hydro Grip Gel Concealer](https://thecastindex.com/beauty/milk-makeup-hydro-grip-gel-concealer)
- [ILIA Super Serum Skin Tint SPF 40](https://thecastindex.com/beauty/ilia-super-serum-skin-tint-spf-40)
- [Round Lab Birch Juice Moisturizing Sun Cream SPF50+ PA++++](https://thecastindex.com/beauty/round-lab-birch-juice-moisturizing-sun-cream)
- [SKIN1004 Madagascar Centella Hyalu-Cica Water-Fit Sun Serum](https://thecastindex.com/beauty/skin1004-madagascar-centella-hyalu-cica-water-fit-sun-serum)
- [Biodance Bio-Collagen Real Deep Mask](https://thecastindex.com/beauty/biodance-bio-collagen-real-deep-mask)

## Questions

### Is hyaluronic acid good for oily skin?

Yes. It hydrates without oil, so it suits oily and combination skin that still feels dehydrated.

### Does hyaluronic acid need a moisturiser on top?

It helps. Hyaluronic acid attracts water; a moisturiser helps keep that water in the skin, particularly in dry or heated air.

### What is sodium hyaluronate?

The salt form of hyaluronic acid, commonly used in skincare. On labels it does the same job.

## Sources

- [Papakonstantinou et al., “Hyaluronic acid: A key molecule in skin aging”, Dermato-Endocrinology, 2012](https://pmc.ncbi.nlm.nih.gov/articles/PMC3583886/)
- [DermNet — Emollients and moisturisers](https://dermnetnz.org/topics/emollients-and-moisturisers)

General information, not medical advice.