Butylene glycol is a common ingredient in many skin care products. In addition to softening and moisturizing the skin t acts as a solvent for ingredients and enhances their stability, texture, and absorption.

Manufacturers add butylene glycol to a vast range of skin care, hair, and beauty products. They often use it instead of a similar compound called propylene glycol, because it may be less irritating to the skin.

Some people have concerns over the safety of butylene glycol. However, many organizations consider it to be safe.

In this article, we discuss butylene glycol in further detail, including its uses, benefits, and side effects. We also explore how butylene glycol differs from propylene glycol.

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Butylene glycol is an organic alcohol, or diol, derived from distilled corn, petroleum, and sugarcane. It is a colorless, viscous, water-soluble liquid that many manufacturers add to skin care products.

Chemically, butylene glycol refers to a structure with four carbon atoms with two alcohol groups.

Some manufacturers also use the ingredient as an alternative to or replacement for propylene glycol, another common skin care ingredient.

Many companies add butylene glycol to their products, including cleansers, face masks, and eyeliners. They use it for its range of properties.

Hydrates the skin

Butylene glycol has humectant properties. Humectants attract and bind water, often from deeper layers of the skin into the top layers. They help keep the skin hydrated and moisturized.

Softens and moisturizes

Aside from drawing moisture to the skin, butylene glycol is also an emollient. It coats the skin’s surface, creating a barrier that prevents water loss.

It also conditions and softens the skin and hair.

Maintains texture

Butylene glycol’s primary role in most skin care products is to act as a solvent.

Solvents help ingredients stay suspended in formulas, preventing them from clumping together or becoming gritty.

Reduces viscosity

Butylene glycol helps reduce the product’s viscosity, stopping other ingredients from sticking together.

This is important to maintain the smooth consistency of products so that a person can effortlessly and evenly apply them to their bodies.

Stabilizes products

Butylene glycol also acts as a stabilizer, preventing active ingredients and volatile compounds from losing their flavor and aroma. Moreover, it prevents products from crystallizing and drying out.

Acts as a preservative

Butylene glycol has antimicrobial properties, which helps boost the effectiveness of preservatives in formulations. It also helps protect against spoilage due to contamination by microorganisms.

A 2021 study found that adding butylene glycol to chitosan, which is a type of fiber, enhanced its antibacterial and antioxidant properties. It also found that the combination had a potent preservative effect in cosmetics.

Furthermore, according to a 2018 study, butylene glycol 25% concentration was effective against all the microbial strains that underwent testing.

Treats acne symptoms

According to an older study, butylene glycol is an ingredient that manufacturers commonly use in anti-acne moisturizers.

While butylene glycol has no direct action against acne, its antimicrobial and moisturizing properties may help treat associated symptoms in acne-prone skin.

Experts consider butylene glycol safe for use in skin care and cosmetics. The Environmental Working Group gives it grade 1 on a 1–10 scale, with 10 being the most harmful.

In 2011, the Cosmetic Ingredient Review board, a panel overseeing the safety of skin care ingredients, determined it safe to use. The Food and Drug Administration (FDA) considers it safe as a food additive.

Older research suggests that allergy to butylene glycol is not common. However, a person should consider conducting a patch test before using a new product.

People with sensitive skin may find that butylene glycol causes skin irritation. Also, the ingredient may irritate the eyes when a person accidentally applies it around or to the eyes. They should ensure to wash the substance away from the eyes.

Pregnant and breastfeeding individuals may consider avoiding products with butylene glycol. There is limited research on its safety for this population. However, an old study documents the adverse effects of butylene glycol on baby rats born to pregnant rats who received the ingredient.

A pregnant or breastfeeding person may wish to consult a doctor for further guidance.

Propylene glycol and butylene glycol have several similarities. Both are colorless liquids derived from petroleum and used as solvents, and both have similar roles in skin care formulations.

Like butylene glycol, propylene glycol is generally considered safe to use as an ingredient in skin care products and a food additive.

Also, manufacturers use both as antifreeze. While this is true, both are low in toxicity compared with another, similar yet toxic ingredient called ethylene glycol. This compound is common in antifreeze and can cause poisoning.

Manufacturers use propylene glycol more than butylene glycol. They may use propylene glycol as a drug stabilizer, food additive, texturizer, or antifreeze.

Propylene glycol may be more irritating to the skin than butylene glycol. The former was dubbed the American Contact Dermatitis Society‘s Allergen of the Year in 2018. Many companies have switched to butylene glycol.

Manufacturers use butylene glycol in a vast range of skin care products as a moisturizer, solvent, humectant, and preserving agent.

While experts consider butylene glycol safe, there are limited studies on its long-term effects. Short-term side effects may include skin irritation and allergies.

A person should consider doing a patch test before using products containing butylene glycol.