Propanediol is a glycol derived from natural or synthetic sources, used in cosmetics and personal care products as a solvent, humectant, and conditioning agent. Its ability to enhance hydration and improve formulation texture makes it a versatile ingredient, especially valued in eco-friendly formulations. It is known as a gentler, more sustainable alternative to propylene glycol. 

See Propylene Glycol

Chemical Composition and Structure
Propanediol (1,3-propanediol) is a three-carbon alcohol with two hydroxyl groups (-OH). Its chemical structure allows good water solubility and moisture retention, making it effective as a humectant and solvent.

Physical Properties
Propanediol appears as a clear, colorless, odorless liquid that is fully miscible in water. Its lightweight, non-sticky texture makes it ideal for skincare, haircare, and makeup products.

Production Process
Propanediol can be produced through the fermentation of natural sugars (from corn or other plant sources) or via a synthetic chemical process. Natural fermentation is the preferred choice for eco-sustainable applications.

Applications

• Medical: Used in dermatological products to enhance the penetration of active ingredients and as a hydrating base.

• Cosmetics: Propanediol is commonly used in creams, serums, lotions, and hair products as a humectant, solvent, and conditioning agent. It improves formulation texture, facilitates the solubility of active ingredients, and provides a silky feel to the skin.

INCI Functions

Solvent. It is the substance for dissolving or dispersing surfactants, oils, dyes, flavourings, bactericidal preservatives in solution.In fact, it dissolves other components present in a cosmetic formulation. Solvents are generally liquid (aqueous and non-aqueous).

Viscosity control agent. It controls and adapts, Increasing or decreasing, viscosity to the required level for optimal chemical and physical stability of the product and dosage in gels, suspensions, emulsions, solutions. 

Propanediol is a monomer for the synthesis of various polyesters. Widely used as an intermediate chemical in cosmetics, laminates, solvents, carpets, lubricants.

It is derived from glycerin and is used as a lubricant by the cosmetic and pharmaceutical industries.

Propanediol studies

Molecular Formula: C₃H₈O₂

Linear Formula CH₃CH(OH)CH₂OH

Molecular Weight: 76.095 g/mol

CAS: 26264-14-2

PubChem Substance ID 24864713

MDL number MFCD00064272

Beilstein Registry Number 1340498

• n-propandiol
• Propandiol
• propane diol
• 1,1-Propanediol
• propane-1,1-diol
• ACM26264142

Some interesting studies on the properties and uses of Propanediol

Lactobacillus reuteri NAD(P)H oxidase: Properties and coexpression with propanediol-utilization enzymes for enhancing 3-hydroxypropionic acid production from 3-hydroxypropionaldehyde.

Dishisha T, Sabet-Azad R, Arieta V, Hatti-Kaul R.J Biotechnol. 2019 Jan 10;289:135-143. doi: 10.1016/j.jbiotec.2018.11.010. Epub 2018 Nov 29.

Safety Assessment of Tromethamine, Aminomethyl Propanediol, and Aminoethyl Propanediol as Used in Cosmetics.

Becker LC, Bergfeld WF, Belsito DV, Hill RA, Klaassen CD, Liebler DC, Marks JG Jr, Shank RC, Slaga TJ, Snyder PW, Gill LJ, Heldreth B.Int J Toxicol. 2018 May/Jun;37(1_suppl):5S-18S. doi: 10.1177/1091581817738242.