Why So Many Skincare Products Contain Butylene Glycol – Is It Safe For Your Skin?

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If you want better skin, it’s so important to have a little bit of knowledge about common ingredients used in skincare products. Not only is it important to know what ingredients your skin would really benefit from, but it’s equally important (or maybe even more so) to know which ingredients might be damaging for your skin or health.

Since I’ve been trying to improve my skin with Korean skincare (and reading countless ingredient lists), I’ve noticed that butylene glycol is an ingredient that is present in almost every single skincare product! So, it’s time to find out: what is butylene glycol used for in skincare products and is it safe to put this ingredient on my skin?

In short, butylene glycol is a chemical compound commonly used as an alternative to propylene glycol or glycerol in skincare products. It has been approved as safe by The Cosmetic Ingredient Review (CIR), the FDA, and the World Health Organization. Additionally, scientific studies have shown no harmful effects from this ingredient and it has therefore been concluded that butylene glycol is non-toxic and non-irritating ingredient.

Although the safety hazards associated with butylene glycol are very well understood and studied, people with very sensitive skin may find butylene glycol irritating (at higher concentrations). It is also possible to have an allergy to butylene glycol – however this is very rare.

I‘ll discuss all this and more in this post, so grab that green tea (it’s good for your skin) and let’s learn about butylene glycol.

What Is Butylene Glycol?

I’ve already told you a little bit about butylene glycol in my intro, but let’s dig deeper.

Chemically, butylene glycol is a type of molecule that consists of 4 carbon atoms and two OH (alcohol) groups. It’s similar to propylene glycol (which has 3 carbon atoms instead of 4) and glycerol (which has 3 carbon atoms, but with an additional alcohol group). Butylene glycol is slightly larger in size compared to propylene glycol and glycerol (due to the additional carbon atom it has).

I found out that there are actually four types of butylene glycol. They are all referred to by the same name (although their chemical names are different) and only differ slightly in their chemical structure (the location of two alcohol groups on the molecule). The differences in the molecular structure of butylene glycol gives each type slightly different properties – which in turn gives them different functions in skincare products (I’ll discuss more in the next section).

What Is Butylene Glycol Used For In Skincare Products?

Butylene glycol is probably one of the most-widely used skincare ingredients! It’s commonly used in a wide range of skincare and cosmetic products, such as cleansers, serums, moisturizers, sunscreen, sheet masks, foundation and mascara. It’s also used in other personal products such as toothpaste, shaving cream and shampoo.

I bet if you checked the ingredients list of your skincare products (you can do that here), that most of them would contain butylene glycol – and the ones that don’t may contain propylene glycol or glycerol instead.

korean double cleansing routine oil cleanser water foaming cleanser COSRX banila co clean it zero cleansing balm
My double cleansing duo both contain butylene glycol

The reason why most skincare products contain butylene glycol is because it is very effective at increasing the skin penetration by other ingredients (many active ingredients have a molecular weight that is too large for effective skin penetration).

Butylene glycol is also often used as a skincare ingredient to give products (such as moisturizers and sunscreens) a thinner consistency – making them feel less greasy and easier to apply.

Lastly, butylene glycol also has humectant properties due to it’s alcohol groups. This means that it has the ability to draw moisture (water molecules) from the surrounding air and keep your skin hydrated (similar to how hyaluronic acid works).

I mentioned above that there are actually four different forms of butylene glycol, which all differ by the location of their two alcohol groups. I just want to summarise quickly what these forms are and what function they have in skincare products:

  • 1,2-butanediol: This form has been shown to increase skin penetration of other ingredients. It is also used as a humectant, solvent and is used to decrease the overall viscosity of a product.
  • 1,3-butanediol: The most commonly used form of butylene glycol. It’s used as an alternative to propylene glycol and glycerol as it has better solvency. It’s also used as a humectant and to reduce viscosity of products. These properties make it effective at preventing products from drying out and other ingredients from crystallising. The safety hazards associated with 1,3-butanediol have been very well researched. It has been concluded that it is non-toxic and does not cause irritation from topical application at the concentrations used in skincare products and cosmetics.
  • 2,3-butanediol: This form isn’t used in skincare products and cosmetics, although it has been shown to be a potential viscosity reducer. It’s toxicity is not fully understood yet, although it’s thought to have minimal toxic effects as it’s found naturally in cocoa butter and sweet corn.
  • 1,4-butanediol: This form of butylene glycol is predominantly used as a solvent in cosmetic products, but it isn’t used very often due to it’s limited properties. It is mostly used in eye products as it causes minimal irritation to the eye area.

Is Butylene Glycol Safe For Skin?

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Butylene glycol is synthetically derived from petroleum, which has given it a somewhat bad name (as people associate it with gasoline or crude oil).

However, it has been concluded (through many studies) that butylene glycol has a low order of toxicity when used in skincare and cosmetic products and is therefore approved as safe by The Cosmetic Ingredient Review (CIR), the FDA, and the World Health Organization.

Studies investigating the effect of undiluted butylene glycol on human skin also found that it produces a very low order of primary skin irritation. Even repeated patch tests on produced no evidence of skin sensitization.

Although butylene glycol has been shown to produce a very low order of primary skin irritation (even when undiluted), it can cause skin irritation for people with very sensitive skin, especially if applied around the eyes.

Just like with any other ingredient, it is also possible for some people to have an allergy to butylene glycol (see study here) – although it is extremely rare. This is why it’s always important to patch test any new skincare product first.

It’s also important to know, that if you have very sensitive skin and would like to choose products containing natural ingredients (instead of butylene glycol), that these have the potential to cause irritation too (such as botanical extracts, citrus oils and tea tree oil).

Should You Avoid Butylene Glycol During Pregnancy?

A very common question is whether butylene glycol is safe to use on your skin during pregnancy.

Unfortunately, there is not enough information available to give a yes or no answer to this question. Only one study looked at the affect that butylene glycol has on the reproductive physiology of rats (which observed changes in neuronal and liver protein synthesis in the developing offspring of rats that were fed butylene glycol during pregnancy).

It’s not much information to go by, so I’d say it really comes down to a personal choice. During my pregnancy, I limited the amount of skincare products I was using so that I was avoiding as many chemicals as possible overall. If you are pregnant and have concerns about butylene glycol (or other ingredients or chemicals), I’d advise to go speak with your doctor for more information.

Is Butylene Glycol Comedogenic?

When it comes to skincare products, many contain certain ingredients that are comedogenic (meaning that they are likely to clog your pores and cause what is known as a comedome). A comedome is simply a type of bump (pimple) on the skin. It can either be open (blackhead) or closed (whitehead).

If you have acne prone skin, you need to be extra careful to avoid skincare products that contain comedogenic ingredients, since you probably have pores that are more prone to getting clogged.

But here’s the thing: some ingredients are more comedogenic than others (there is a comedogenic scale), and even the ones that are considered to be the most comedogenic won’t cause comedomes and acne for certain. This is because it all comes down to your individual skin (such as your pore size) and how the product you’re using is formulated.

So is butylene glycol comedogenic? Although it is considered a comedogenic ingredient, it’s only rated as a category 1 ingredient on the comedogenic scale (where ingredients in category 0 will not clog pores and those in category 5 have a high probability that they will clog pores). So, in other words, there is a very low probability that butylene glycol will clog your pores and cause you to breakout.

Skincare Products Without Butylene Glycol

Although butylene glycol has been approved to be safe for skin, I mentioned above that some people may have an allergy to butylene glycol (although it seems to be very rare). Since the majority of Korean skincare products do contain butylene glycol, it can feel like a lost cause trying to find products without it.

You can find a very detailed (and continuously updated) list containing Korean and Western skincare brands and products that contain no or a very low concentration butylene glycol here. Thank you to the person that put together this wealth of information!

I always advise to check up-to-date ingredient lists and do a patch test before using a product. Two great places to find ingredient lists are CosDNA and SkinCarisma.

Conclusion

Butylene glycol is a skincare ingredient that can be found in almost every skincare product (especially Korean skincare products). It’s used to improve some of the properties of skincare products.

Many studies have been conducted over the years and these have led to the understanding and approval that butylene glycol is a safe ingredient when used in skincare and cosmetic products.

However, people with very sensitive skin may experience irritation when using products containing butylene glycol, and although very rare, it is possible to have an allergy to this ingredient too.

I hope I’ve answered some of the questions you may have had about butylene glycol. Let me know if you have any other questions and I’ll try my best to answer them for you.