Why is PG (Propylene Glycol) Used in Skin Care Products?

What is PG (Propylene Glycol)?

PG (propylene glycol) is a synthetic alcohol used as a cosmetic ingredient. It is a slightly viscous, colorless, transparent liquid.

It is used as a solvent to dissolve moisturizers and other ingredients. It also functions as an emulsifier to mix water-based and oil-based ingredients. It is also used in many cosmetics, including skin care products, because it has a variety of other expected effects.

Benefits of adding PG to cosmetics

PG is used in many cosmetics, including skin care products such as lotions and milky lotions, hair care products such as soaps and shampoos, and deodorant products. The main reasons for its inclusion are as follows:

Has antiseptic properties

PG has antibacterial properties that inhibit the growth of microorganisms, which helps extend the shelf life of skin care products.

Has moisturizing effects

PG has a strong affinity for water. It attracts moisture and keeps it there, making the skin supple and moisturized. This is why PG is used as a moisturizer in cosmetics.

Increased penetration power

Another effect of adding PG is that it helps other ingredients and active ingredients penetrate the skin more easily. If you notice any changes in your skin after using your favorite beauty serum, it may be due to the PG that is added to it.

PG is used in a variety of things

In addition to cosmetics, PG is also used as an additive in the following products:

• Food mold inhibitor
• Antifreeze for cooling equipment in chemical plants and refrigerated warehouses
• Heat and cold transfer fluids and hydraulic oils in chemical plants and industrial machinery
• Plasticizer

You may be concerned to know that these same substances are in the skin care products you use every day.

However, PG is said to pose no risks such as carcinogenicity, endocrine disruption , or reproductive toxicity. Its high safety is why it is used in so many products.

Is PG gentle on the skin?

Although it is considered to be highly safe, it has been pointed out that PG can cause allergic contact dermatitis in some people. As mentioned above, PG increases the skin's penetration ability, but this high penetration ability may actually cause skin irritation.

It is said that PG is particularly likely to cause contact allergic dermatitis in the following people:

• People who already have skin diseases such as eczema or atopic dermatitis
• People with a history of allergies
• People with sensitive skin

The US Environmental Working Group suggests that even low concentrations of 2% can cause skin irritation and contact dermatitis, and in 2018, it was selected as Allergen of the Year by the American Contact Dermatitis Society.

Conflicting risk assessments

PG has been pointed out for its allergenicity and skin sensitization for many years, but in fact, its evaluation is still under debate.

For example, a 2005 report analyzing patch test data from 45,138 people revealed the following results: *Patch test using a 20% PG aqueous solution

• 1,044 people (2.3%) tested positive
• 1,083 (2.4%) had suspicious or erythematous reactions
• 271 people (0.6%) had a clear irritation reaction

Opinions are divided as to whether this number of positive reactions is high or low.

Additionally, a 2023 report noted that PG has conflicting evaluations of its skin sensitization and allergy potential, meaning that while some clinical data show it to be a weak allergen, other test data show no evidence of skin sensitization.

Despite its long history of use and the large amount of data available, reviews are mixed, so it may be some time before a definitive evaluation is available.

As a precaution, it might be a good idea to choose products that are gentler on your skin.