Common Name(s): 1,3-butylene glycol alternative,2-methyl-1,3-propanediol,proline-2-propanediol

CAS Number: 2163-42-0

DESCRIPTION

What It Does: Provides humectant and solvent functionality with improved skin feel vs butylene glycol.

Why It's Used: Premium humectant solvent with superior skin feel to conventional diols for elegant premium formulation textures.

How It Works: Branched c4 structure provides good humectant activity. branching reduces viscosity and stickiness vs linear propylene glycol. excellent solvent for challenging actives. antimicrobial boosting from diol structure.

Typically Found In: Premium serums,active delivery systems

TECHNICAL DETAILS

Primary Category: Functional ingredient – humectant

Secondary Functions: Tewl reduction,skin plumping

Application Areas:

Typical Concentration Range: 1%–10%

SOURCING & ETHICS

Vegan Status: Yes – synthetic

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

Methylpropanediol's methyl branch provides a 25% reduction in dynamic viscosity vs linear butylene glycol at equivalent concentration — a physically measurable skin feel improvement from the branching's reduction of intermolecular attractive forces. this viscosity reduction translates directly to the 'less sticky, lighter' skin feel that premium formulations require.

Last Verified: 2026-03-12

Primary Sources: Cosing database,cir safety assessment