Propylene glycol: composition, application, risks.


Propylene Glycol is a synthetic liquid that is used for a variety of purposes in the pharmaceutical, cosmetic, food, and manufacturing industries. It is usually odorless, tasteless and colorless, and its texture is somewhat oily or syrupy .

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What is it

Propylene Glycol is a water absorbing alcohol and is completely miscible with many solvents. While you can see that propylene glycol is described as an organic compound, this does not mean that it occurs naturally. Rather, the term "organic compound" refers to the fact that it contains carbon.

Although it is a liquid, propylene glycol can vaporize into air when heated or vigorously shaken. The FDA considers propylene glycol to be safe and non-toxic.


Propylene glycol can be obtained in two ways. It is made primarily by treating propylene oxide with water, a chemical produced in petroleum refining .

Propylene glycol can also be obtained from glycerin, an important by-product of the biodiesel manufacturing process. This type of propylene glycol is used mainly for industrial purposes such as the manufacture of plastics or antifreeze.


Propylene Glycol is used in a variety of products and manufacturing processes.

Pharmaceutical products

Propylene glycol is widely used as a solvent in drug manufacturing. This means that it is used to dissolve other substances (usually solid) without changing their basic structure or composition.

Propylene glycol is also used as a vehicle in dosage forms. Active ingredients can be formulated in it and delivered to the body through it. Finally, it is used to dilute and stabilize drugs.

Propylene glycol can be used in a variety of drug forms, including oral medications such as capsules and tablets, topical medications such as creams and gels, and intravenous (injectable) medications.

Cosmetic tools

Propylene Glycol is an ingredient commonly found in cosmetic, personal, and skin care products. Its content ranges between 26.4% and 37.8% of registered personal hygiene products. Propylene glycol is a versatile substance and performs many functions in the composition of the products in which it is included. Some of these features:

  • Moisturizer : Moisturizers are found in cosmetics and skin care products due to their hydrating properties. Propylene glycol acts as a humectant, drawing moisture to the skin, thereby moisturizing and hydrating it.
  • Solvent : Propylene Glycol is used to dissolve substances in a product so that they mix properly and work together. It also acts as a carrier for active ingredients.
  • Emollient : Emollients are ingredients that soothe and hydrate the skin. They are very useful in dry skin care products. Propylene glycol is used as an emollient because it forms an oily layer on the skin and prevents water loss.
  • Viscosity control : Propylene glycol is used to reduce the thickness of cosmetic formulations and products. This helps them to spread better on the skin and also improves the absorption of the products.
  • Preservative : Glycol porpeling is often used in combination with other chemicals as a preservative in beauty products and skin care products.


Propylene Glycol is widely used in food and is considered safe. When consumed, propylene glycol breaks down fairly quickly in the body, within 48 hours, and becomes a source of energy.

Unlike similar substances like ethylene glycol, propylene glycol does not form harmful crystals as it breaks down in the body. Its quantity, which is neither degraded nor metabolized, is excreted in the urine .

Here are some of the ways that propylene glycol can be used in food :

  • As an anti-caking agent to help prevent the formation of lumps in food.
  • As a food flavoring solvent, it helps dissolve and mix ingredients.
  • As a mass enhancer
  • To improve the palatability of food.
  • As a preservative, its antimicrobial properties help kill and / or prevent the growth of microorganisms such as bacteria and mold.
  • Food thickener
  • To retain moisture in food.

Propylene glycol is safe to consume and the FDA approves its use in food in certain concentrations. May be up to 97% condiments and flavors, 24% confectionery and glazes, and 5% alcoholic beverages and dried fruit / tree nut products.

For dairy products and all other food products, the maximum propylene glycol concentration is 2.5% and 2%, respectively .


Propylene Glycol lowers the freezing point of water and water-based fluids, making it an effective antifreeze. Propylene glycol makes up a large part of aircraft de-icers and is also used to break ice on airport runways.

Since propylene glycol is non-toxic, it is also often used as an antifreeze in food processing systems and in water pipes leading to connecting hoses.

Electronic cigarettes

In addition to vegetable glycerin, propylene glycol is the main ingredient in e-liquids (e-liquids) used in electronic cigarettes . To simulate smoke, propylene glycol turns into very small droplets in e-cigarettes. It also works as a carrier for nicotine and flavorings that are added to some e-liquids.

UPDATE January 2020: Recent illnesses have been linked to e-cigarette use (vaping). Since the specific causes of these cases of lung damage are not yet known, the Centers for Disease Control and Prevention (CDC) recommends avoiding all smoking products .

Recent research suggests that the use of e-cigarettes can have harmful effects on your health and that some of these effects may be due to the mixture of propylene glycol and other ingredients. Some of these health risks include lung damage and lung disease .

Other studies also show that propylene glycol turns into cancer-causing compounds when heated in e-cigarettes. Research on these risks associated with e-cigarettes is still ongoing and the risks have yet to be definitively identified.


Some people may experience skin irritation or contact dermatitis from frequent exposure to propylene glycol. This exposure could be through cosmetic products. topical foods or medications.

Get the word of drug information

Propylene Glycol is a synthetic substance that has many uses in the industrial, pharmaceutical, food, and cosmetic industries. Propylene glycol is safe and non-toxic at levels that people typically consume or are exposed to.

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