Hyaluronic acid

Humectant0.1–1%

A moisture-binding molecule that helps skin look plumper and feel hydrated, suited to nearly everyone.

What it is

Hyaluronic acid is a sugar-based molecule the skin makes naturally, and for cosmetics it is now mostly made by fermentation. It holds water at the skin's surface, so skin feels softer and fine dehydration lines look less visible. It is gentle and works in almost any water-based product.

Good for

Dehydrated skinFine linesPlumper skinSensitive skin

How it works

Hyaluronic acid attracts and holds water. Larger molecules stay on the surface as a light, moisture-holding film, while smaller fragments reach the upper layers of the skin. Blending sizes gives both instant smoothness and longer-lasting hydration.

Ratings

Evidence

4/5

Consistent measured hydration data, but fewer trials on wrinkles.

Gentleness

5/5

Very well tolerated and suits even sensitive skin.

Formulation difficulty

2/5

Easy in water phases, though salts, low pH and heat thin it.

Cost

2/5

Low cost at typical levels, though cross-linked grades cost more.

Popularity

5/5

A top-three searched skincare ingredient in 2024.

Pairs and cautions

Pairs well with

In a routine. Pairing in one formula depends on matching pH windows.

Take care with

High-salt or very low-pH basesThin the gel
High doses of high-weight gradesTacky feel, pilling under makeup

Formulations it suits

Serum Toner, essence and face mist Cream Gel Gel-cream Sheet mask Eye cream

Packaging

Regional considerations

Australia	Unscheduled for topical use at any strength; the Poisons Standard lists hyaluronic acid in Schedule 4 only for injection or implantation, such as dermal fillers.
ASEAN	Indonesia requires halal certification for cosmetics by 17 October 2028, so specify fermentation-derived hyaluronic acid with a halal certificate rather than rooster-comb material.

In the lab

Specifications

Typical use level

0.1–1%0525%

pH window

pH 5–72 acid7 neutral10 alkaline

Solubility

Water-soluble

Sensitive to

HeatLow pHHigh pH

0.1–0.5% in most moisturisers and serums; dedicated hydrating serums use 1–2%.

INCI	Sodium Hyaluronate
Also known as	HA, Hyaluronan
Origin	biotech/fermentation

Lab notes

Solubility and phase

Water phase. It hydrates slowly, so pre-disperse it in glycerin or sprinkle it into the vortex.

Stability

Disperse with low shear and add low-weight grades in cool-down. Keep it away from prolonged heat, strong acids or bases and oxidisers, which break it down.

Regulatory, Australia

Hyaluronic acid and sodium hyaluronate are on the AIIC, with no EU restriction. The Poisons Standard schedules hyaluronic acid only for injection or implantation, not for topical cosmetics.

Claims to take care with

Hydration and 'plumper-looking' claims are cosmetic, but avoid comparisons with injectable fillers or 'fills wrinkles'. Vegan or Halal claims need the supplier's certificate for each grade.