Common Name(s): Agar-agar,agarose,gelidium amansii extract

CAS Number: 9002-18-0

DESCRIPTION

What It Does: Provides firm, thermally reversible marine-derived gels from natural seaweed polysaccharide.

Why It's Used: Natural seaweed gellant for clean beauty formulations requiring firm, stiff gel textures with authentic marine provenance.

How It Works: Agarose chains form double helix junction zones that aggregate into bundles forming a rigid gel network below 38°c. melts at 85°c but re-gels at 38°c – this 47°c hysteresis window means agar gels remain solid at skin contact (33°c) but dissolve cleanly in hot water for rinse-off products.

Typically Found In: Sheet masks,gel cleansers,firm gel products

TECHNICAL DETAILS

Primary Category: Functional ingredient – seaweed gellant

Secondary Functions: Tewl reduction,skin plumping

Application Areas:

Typical Concentration Range: 0.5%–3%

SOURCING & ETHICS

Vegan Status: Yes – from red seaweed

Halal Status: Yes

Source Notes: Synthetic or naturally derived. excellent aqueous solubility.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Non-irritating; suitable for all skin types.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Excellent safety profile. ewg score: 1.

Works Well With: Ceramides,emollients,occlusives,glycerin,hyaluronic acid

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Agar's thermal hysteresis (melts 85°c, sets 38°c) is unique among natural gellants. this hysteresis arises from the different temperatures required for helix-coil disruption (melting) vs helix formation (setting) in the agarose chains. the practical consequence – a gel that can be sterilized at 121°c yet remains stable at skin temperature (33°c) – makes agar uniquely useful for thermally stable cosmetic gels.

Last Verified: Cosing database,cir safety assessment,fda gras

Primary Sources: 2026-03-12