Difference Wiki

Polyethylene Glycol vs. Propylene Glycol: What's the Difference?

Edited by Aimie Carlson || By Harlon Moss || Published on December 26, 2023
Polyethylene glycol is a polymer used in laxatives and lubricants, while propylene glycol is a small organic alcohol used in food and cosmetics.

Key Differences

Polyethylene glycol (PEG) is a polyether compound, a long-chain polymer of ethylene oxide. Propylene glycol is a small, diol alcohol derived from propane.
PEG is used in pharmaceuticals as a laxative, in personal care products as a lubricant, and in industrial applications. Propylene glycol is used in food as a humectant, in pharmaceuticals, and in cosmetic products as a skin-conditioning agent.
PEG varies in consistency from liquid to solid, depending on its molecular weight. Propylene glycol is a viscous, colorless liquid.
PEG is generally considered safe for use in pharmaceuticals and cosmetics, with varying safety based on molecular weight. Propylene glycol is recognized as safe for use in food and cosmetics, but can be irritating at higher concentrations.
PEG is soluble in water and many organic solvents, stable, and non-volatile. Propylene glycol is also water-soluble, hygroscopic, and maintains stability in various chemical environments.

Comparison Chart

Chemical Structure

Long-chain polymer of ethylene oxide
Small diol alcohol derived from propane

Common Uses

Laxatives, lubricants, industrial
Food humectant, pharmaceuticals, cosmetics

Physical Form

Ranges from liquid to solid
Viscous, colorless liquid


Generally safe, varies with molecular weight
Generally safe, irritating at high concentrations

Solubility and Stability

Soluble in water and organic solvents, stable
Water-soluble, hygroscopic, chemically stable

Polyethylene Glycol and Propylene Glycol Definitions

Polyethylene Glycol

Varies in form from liquid to solid based on molecular weight.
The polyethylene glycol in the solution was in its liquid form.

Propylene Glycol

Recognized as safe for use in food and cosmetic products.
Propylene glycol is used in many cosmetic creams due to its safety profile.

Polyethylene Glycol

Soluble in water and used in various industrial applications.
Polyethylene glycol's solubility makes it useful in many industrial processes.

Propylene Glycol

A small organic alcohol used in food and cosmetics.
Propylene glycol is commonly found in many food flavorings.

Polyethylene Glycol

A polymer used as a laxative and lubricant.
Polyethylene glycol is a key ingredient in many over-the-counter laxatives.

Propylene Glycol

Used in pharmaceuticals as a solvent and carrier.
The medication used propylene glycol to dissolve and carry the active ingredient.

Polyethylene Glycol

Considered safe for use in cosmetics and pharmaceuticals.
The skincare product contained polyethylene glycol for its moisturizing properties.

Propylene Glycol

Acts as a humectant in food products.
Propylene glycol helps to retain moisture in packaged baked goods.

Polyethylene Glycol

Used in pharmaceuticals for its lubricating properties.
Polyethylene glycol helps to ease the application of certain creams.

Propylene Glycol

A colorless, viscous liquid with hygroscopic properties.
The propylene glycol in the formulation contributed to its thicker texture.


Can polyethylene glycol be used in food?

Not typically used in food; more common in pharmaceuticals and cosmetics.

What are common uses of polyethylene glycol?

As a laxative, lubricant, and in industrial applications.

What is polyethylene glycol?

A polymer used in pharmaceuticals, personal care, and industry.

Is polyethylene glycol safe?

Generally safe, but safety varies with molecular weight.

Is propylene glycol safe in cosmetics?

Yes, it's recognized as safe but can be irritating in high concentrations.

What is the physical state of propylene glycol?

A colorless, viscous liquid.

How does polyethylene glycol vary in form?

It ranges from liquid to solid based on its molecular weight.

How does polyethylene glycol affect skin care products?

It acts as a moisturizer and enhances the texture of products.

What is propylene glycol?

A small organic alcohol used in food, pharmaceuticals, and cosmetics.

Can propylene glycol be used in medications?

Yes, as a solvent and carrier for active ingredients.

Is polyethylene glycol toxic?

Generally non-toxic, but toxicity can depend on molecular weight.

Can polyethylene glycol cause allergies?

Rare, but possible, especially in individuals with sensitive skin.

How does propylene glycol affect pharmaceutical formulations?

It improves the solubility and stability of medications.

What are the uses of propylene glycol in food?

As a humectant, solvent, and to retain moisture.

How is polyethylene glycol used in laxatives?

It helps to retain water in the stool, easing bowel movements.

Is propylene glycol a natural ingredient?

It's synthetically made, but it's used in both synthetic and natural formulations.

Is propylene glycol the same as ethylene glycol?

No, they are different compounds; ethylene glycol is more toxic.

Can propylene glycol be used as an antifreeze?

Yes, it's used in antifreeze formulations.

What is the role of propylene glycol in baked goods?

It helps to maintain moisture and extend shelf life.

What industries use polyethylene glycol extensively?

Pharmaceuticals, personal care, and various industrial sectors.
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

Trending Comparisons

Popular Comparisons

New Comparisons