BUTYLENE GLYCOL

Synonyms:
Butylene Glycol;  1,3-Butanediol; 
2-Butoxyethanol, butyl cellosolve, butyl glycol, ethylene glycol monobutyl ether, Dowanol; Cas No: 111-76-2; 2-butoxyethanol; butylcellosolve; ethyleneglycol monobutyl ether; n-butoxyethanol; n-butoxyethanol sodium salt; 2-Butoxyethanol; Butoxyethanol; Butyl glycol; 111-76-2; Butyl cellosolve; ETHYLENE GLYCOL MONOBUTYL ETHER; Ethylene glycol butyl ether; n-Butoxyethanol; Ethanol, 2-butoxy-; Butyl oxitol; 2-butoxyethan-1-ol; 2-Butoxy-1-ethanol; Dowanol EB; Gafcol EB; Glycol butyl ether; Poly-Solv EB; 3-Oxa-1-heptanol; 2-bütoksietanol; Etilen Glikol Mono Butil Eter; BG Eter; Glikol Butil Eter; 2-Butoksi etanol; 2-n-Butoksietanol; Eter Alkol; Butyl Glycol; Butyglcol; Etilen Glikol, monobutil eter; Butil Monoeter Glikol; Butil 2-hidroksietil eter; Solvent; Butil Selüloz; Etanol-2-butoksi-; 111-76-2; Butoxyethanol; Butyl Glycol; Butyl cellosolve; Butyl glycol; Butyl monoether glycol; EGBE (ethylene glycol monobutyl ether); Dowanol EB; Bane-Clene; Eastman EB solvent; BH-33 industrial cleaner; Solvaset; 2-BE; EGMBE; Butyl oxitol; Ektasolve; Jeffersol EB; BUTYL GLYCOL; BÜTİL GLİKOL; BUTİL GLİKOL; BUTİL GLİYKOL; BÜTHİL GLİCOL; BÜTİL GLİKOL;BUTHYL GLYCOL; BÜTYİL GLİKOL; BUTİL GLİKOL; BUTİL GLİYKOL; BÜTHİL GLİCOL; BÜTİL GLİKOL; butyl glycol; bütil glikol; Bütil Glikol; butil gliykol; büthil glicol; bütil glikol; Butyl Glycol; Bütil Glikol; Bütil Glikol; Butil Gliykol; Büthil Glicol; Bütil Glikol; bütil gilikol; BUTİL GLİKOL; Bütil Glikol; butil gliikol; 1,3-BUTANEDIOL; Butane-1,3-diol; 110-63-4; 1,3-Butylene glycol; Tetramethylene glycol; 1,3-Dihydroxybutane; 1,3-Tetramethylene glycol; Tetramethylene 1,3-diol ; Sucol B; 1,3-BD; 1,3-BUTANEDİOL
1,3-BUTANEDIOL; 1,3-BÜTANEDIOL; 1,3-BUTANEDiOL; 1 4-BUTANEDIOL; 1,3 BUTANEDIOL; 1,3-BUTANE DIOL; 1,3-BUTANEDIOLE; 1,3-BUTANEDİOLE; 1,3-BÜTANEDİOLE; 1,3-BÜTANDİOL; 1,3-BÜTAN DİOL; 1,3 – BÜTANDİOL; 1,3-BÜTANDİOLE; 1,3 BÜTANDİOL; 1,3-BÜTAN DİOLE; 1 4 BÜTANDİOL;  1,3-butanedıol; 1,3-bütanedıol; 1,3-butanediol; 1 4-butanedıol; 1,3 butanedıol; 1,3-butane dıol; 1,3-butanedıole; 1,3-butanediole; 1,3-bütanediole; 1,3-bütandiol; 1,3-bütan diol; 1,3 – bütandiol; 1,3-bütandiole; 1,3 bütandiol; 1,3-bütan diole; 1 4 bütandiol; 1,3-Butanedıol; 1,3-Bütanedıol; 1,3-Butanediol; 1 4-Butanedıol; 1,3 Butanedıol; 1,3-Butane Dıol; 1,3-Butanedıole; 1,3-Butanediole; 1,3-Bütanediole; 1,3-Bütandiol; 1,3-Bütan Diol; 1,3 – Bütandiol; 1,3-Bütandiole; 1,3 Bütandiol; 1,3-Bütan Diole; 1 4 Bütandiol
Butane-1,3-diol; 110-63-4; 1,3-Butylene glycol; Tetramethylene glycol; 1,3-Dihydroxybutane; 1,3-Tetramethylene glycol; Tetramethylene 1,3-diol; Sucol B; 1,3-BD; DIOL 14B; Agrisynth B1D; HO(CH2)4OH; NSC 406696; CCRIS 5984; 1,3-Dihdyroxybutane; HSDB 1112; EINECS 203-786-5; HOCH2CH2CH2CH2OH; BRN 1633445; AI3-07553; CHEBI:41189; WERYXYBDKMZEQL-UHFFFAOYSA-N; MFCD00002968; DSSTox_CID_4666; DSSTox_RID_77492; DSSTox_GSID_24666; BDO; BU1; CAS-110-63-4; UNII-7XOO2LE6G3; 4-hydroxybutanol; 1,3butanediol; 1.4-butanediol; Dabco BDO; 1,3-butandiol; 1,3-butane diol; 1,3-butane-diol; butane 1,3-diol; butane diol-1,3; butane-1-4-diol; 1,3- butandiol; Buta
n-1.4-diol; 1.4 - butanediol; butanediol, 1,3-; 1,3 butylene glycol; ACMC-1BRE8; 1,3-Butanediol, 99%; AC1L1Q6L; AC1Q7CS0; WLN: Q4Q; versalink curative 1,3 bdo; 7XOO2LE6G3; akos bbs-00004303; 4-01-00-02515 (Beilstein Handbook Reference); KSC175Q8N; MLS001061198; 1,4-Butanediol 4 M solution; CHEMBL171623; DTXSID2024666; CTK0H5886; KS-00000WMZ; HMS3039N12; LTBB001138; 1,4-Butanediol, 99% 250g; ZINC1599375; Tox21_202245; Tox21_303040; ANW-16175; LS-512; NSC406696; STL283940; AKOS000118735; 1,4-Butanediol, for synthesis, 98%; DB01955; MCULE-2010022287; NSC-406696; RL02831; RP18542; RTR-032026; TRA0075312; 1,4-Butanediol, ReagentPlus(;R), 99%; NCGC00090733-01; NCGC00090733-02; NCGC00257119-01; NCGC00259794-01; 28324-25-6; AJ-27941; AK160801; AN-22614; BP-21418; CJ-05671; CJ-25700; KB-10525; OR012020; SC-79277; SMR000677930; 1,4-Butanediol, ReagentPlus(R), >=99%; TR-032026; B0680; FT-0606811; ST24046254; 3379-EP2272849A1; 3379-EP2292597A1; 3379-EP2301919A1; 3379-EP2305668A1; 1,4-Butanediol, Vetec(TM) reagent grade, 98%; 48881-EP2270101A1; 48881-EP2275417A2; 48881-EP2284162A2; 48881-EP2284163A2; 48881-EP2284165A1; 48881-EP2295399A2; 48881-EP2295438A1; 48881-EP2308865A1; 48881-EP2311841A1; 48881-EP2371797A1; 48881-EP2371798A1; 48881-EP2371805A1; 48881-EP2380568A1; 48881-EP2380873A1; I14-2693; J-503971; J-512798; 3B1-003910; 3B1-004958; 3B1-007610; 3B1-007837; F0001-0222; Z1259087047; InChI=1/C4H10O2/c5-3-1-2-4-6/h5-6H,1-4H; UNII-TMS4MGA0H4 Component; WERYXYBDKMZEQL-UHFFFAOYSA-N; 732189-03-6; 1,4-Butanediol; 1,3-B; BD; One Comma Four; One Four Bee; Butylene Glycol; or One Four B-D-O; BUTANE-1,3-DIOL , TETRAMETHYLENE GLYCOL 1,3-BUTANDIOL; 1,3-Butanediol; ,4-Butanediol 1,3-butylene glycol butylene glycol; ,4-Butylene glycol; ,4-Dihydroxybutane; ,4-Tetramethylene glycol; Butan-1,3-diol; Butane-1,3-diol; Butano-1,3-diol; Butylene glycol; Dabco DBO ;Diol 14B; NSC 406696; Polycure D; POLYESTER OF 1,3-BUTANEDIOL; Sucol B; Tetramethylene 1,3-diol; Tetramethylene glycol; Vibracure A 250; ZM 0025; BUTANEDIOL; 1,3-BUTYLENE GLYCOL; 1,3-TETRAMETHYLENE GLYCOL; 1,3-Butanediol; Butane-1,3-diol; 1,3-Butylene glycol; Tetramethylene glycol;; 110-63-4; 1,3-Dihydroxybutane; 1,3-Tetramethylene glycol; BDO; Butanediol-; 1,3; 1,3-BD; 1,3-BDO; 1,3-Tetramethylene ; 11,3-Butanediol ; 1,3-Butandiol ; 1,3-Butanediol ; 110-63-4 ; butane-1,3-diol; (3S)-Butane-1,3-diol; (S)-()-1,3-Butanediol; [110-63-4]; 1,3-BD; 1,3-butane diol; 1,3-BUTANEDIOL, 99%; 1,3-butylene glycol; 1,3-Dihydroxybutane; 1,3-Tetramethylene glycol; 1,3-丁二醇 ; 1589-49-7 ; 203-786-5 [EINECS]; 25265-75-2 ; 28324-25-6 ; 4-01-00-02515 ; 53504-41-9; 732189-03-6 ; BDO; BU1; BU2; Butane diol-1,3; BUTANEDIOL ; Butylene glycol; Dabco BDO; HO(CH2)4OH; HOCH2CH2CH2CH2OH; InChI=1/C4H10O2/c5-3-1-2-4-6/h5-6H,1-4H; MFCD00002968 ; POLYURETHANE ; ST5214425; Tetramethylene 1,3-diol; bütandiol; bütandiyol; diyol; bütanediyol; butanediyol; BÜTANDİYOL; BUTANDİYOLE; 14bütandiol; 14butandiyole; 14bütandiyol; 1,3-Butylene glycol, Tetramethylene glycol; CAS Number 110-63-4; Linear Formula HO(CH2)4OH; Molecular Weight 90.12; Beilstein Registry Number 1633445; EC Number 203-786-5; MDL number MFCD00002968; pubChem Substance ID 24872855; 1,3-Butanediol; 1,3-B; BD; One Comma Four; One Four Bee; Butylene Glycol; One Four B-D-O; Butane-1,3-diol; 1,3-Butylene glycol; 1,3-Butylene glycol; 1,3-Butanediol; InChI=1S/C4H10O2/c5-3-1-2-4-6/h5-6H,1-4H2; WERYXYBDKMZEQL-UHFFFAOYSA-N; 110-63-4; Diol 14B; Sucol B; Tetramethylene glycol; 1,3-Butylene glycol; 1,3-Dihydroxybutane; 1,3-Tetramethylene glycol; Butane-1,3-diol; Butanediol; 1,3-BD; Tetramethylene 1,3-diol; BDO; Butylene glycol; Dabco BDO; Butane diol-1,3; NSC 406696; 1,4-butylene glycol; 1,4-dihydroxybutane; tetramethylene glycol; 1,4-tetramethylene glycol; tetramethylene-1,4­diol; butylene glycol; butanediol; butane-1,4-diol; BUTANE-1,4-DIOL; BUTANEDIOL; 1,4-BUTANEDIOL; BUTYLENE GLYCOL; 1,4-BUTYLENE GLYCOL; DABCO DBO; DIHYDROXYBUTANE; 1,4-DIHYDROXYBUTANE; DIOL 14B; POLYCURE D; SUCOL B; TETRAMETHYLENE 1,4-DIOL; TETRAMETHYLENE GLYCOL; 1,4-TETRAMETHYLENE GLYCOL; Butanediol; 1,4-; (1,4-tetramethylene glycol) (110-63-4); 1,4-Butylene Glycol; 1,3-Dihydroxybutane; Tetramethylene Glycol; BDO; 1,3-bD; sucolb; diol14b; Sucol B; Diol 14B; Dabco BDO; Butanediol; agrisynthb1d; 4-Butanediol; 1,3-Butanediol ≥99%; 1,3-BD; 1,3-Butylene glycol; 1,3-Dihydroxybutane; 1,3-Tetramethylene; glycol; BDO; Butane diol-1,3; Butane-1,3-diol; Butanediol; Butylene glycol; Dabco BDO; Diol 14B; NSC 406696; Sucol B; Tetramethylene; 1,3-diol; Tetramethylene glycol; InChI=1S/C4H10O2/c5-3-1-2-4-6/h5-6H,1-4H2; InChI Key; WERYXYBDKMZEQL-UHFFFAOYSA-N; Formula; C4H10O2; SMILES; OCCCCO; Molecular Weight1; 90.12; CAS; 110-63-4; 732189-03-6; ECHA EINECS; REACH Pre-Reg: 03-786-5; FDA UNII:7XOO2LE6G3; Nikkaji Web:J5.097K; Beilstein Number:1633445; MDL:MFCD00002968; agrisynth B1D; 1,3-butandiol; butane-1,3-diol; 1,3-butanediol; 1,3-    butylene glycol; 1,3-dihydroxybutane; tetramethylene glycol; 1,3-tetramethylene glycol; Butane-1,3-diol; 1,3-Butylene glycol; 1,3-Dihdyroxybutane; Tetramethylene 1,3-diol; 1,3-Tetramethylene glycol; Tetramethylene glycol; 1,3; 14bd; 1,3-bütandiol ;1,3 bütandiol; 1 4-bütandiol; 1 4 bütandiol
 

BUTYLENE GLYCOL

BUTYLENE GLYCOL
Butylene glycol is an organic alcohol used as a solvent and conditioning agent in cosmetics industry. It is a water soluble, colorless liquid. It is mainly used in leave-on and rinse-off formulations.
BUTYLENE GLYCOL is classified as :
Humectant
Masking
Skin conditioning
Solvent
Viscosity controlling
CAS Number    107-88-0
EINECS/ELINCS No:    203-529-7
COSING REF No:    74756
Chem/IUPAC Name:    Butane-1,3-diol

Summary
Butylene glycol is a chemical ingredient used in self-care products like:

shampoo
conditioner
lotion
anti-aging and hydrating serums
sheet masks
cosmetics
sunscreen
Butylene glycol is included in formulas for these types of products because it adds moisture and conditions hair and skin. It also works as a solvent, meaning it keeps other ingredients, dyes, and pigments from clumping up inside of a solution.

Like all glycols, butylene glycol is a type of alcohol. It’s often made from distilled corn.

There are some health concerns that surround the use of butylene glycol. Some experts warn against its use, and cite it on lists of ingredients to avoid when choosing self-care products.

The risk in using butylene glycol is still somewhat unclear. More research is needed to understand how it can affect your body in the long term.

Butylene glycol uses
Butylene glycol is added to all kinds of products that you apply topically. It’s particularly popular in clear gel-based products and in makeup that glides onto your face.

You’ll find it on the ingredients list of sheet masks, shampoos and conditioners, eye liners, lip liners, anti-aging and hydrating serums, tinted moisturizers, and sunscreens.

Butylene glycol is a viscosity-decreasing agent
“Viscosity” is a word that refers to how well things stick together, particularly in a compound or chemical mixture. Butylene glycol makes other ingredients less likely to stick together, giving makeup and self-care products a fluid and even consistency.

Butylene glycol is a conditioning agent
Conditioning agents are ingredients that add a layer of softness or improved texture to your hair or skin. They’re also called moisturizers or, in the case of butylene glycol, humectants. Butylene glycol works to condition skin and hair by coating the surface of your cells.

Butylene glycol is a solvent
Solvents are ingredients that maintain a liquid consistency in a chemical compound. They help active ingredients that could become gritty or clumpy stay dissolved. Butylene glycol keeps the ingredients in cosmetics spread out and in their desired state for use.

Butylene glycol benefits
Butylene glycol has some health benefits if you have dry skin on your face or frequent breakouts. But it won’t work the same way for every person. Generally, most people who have dry skin can use products with butylene glycol to reduce their symptoms.

Butylene glycol for acne
Butylene glycol is in some moisturizersTrusted Source made for people who have acne. It isn’t the active ingredient that treats acne in these products. The moisturizing and solvent properties in butylene glycol could make these products right for you.

However, there are reports of this ingredient clogging pores or irritating skin and actually making acne worse.

Based on your symptoms, the cause of your acne, and your skin sensitivity, butylene glycol may be an ingredient that works in your skin care regimen.
Butylene glycol side effects and precautions
Butylene glycol is considered to be largely safe for use as a topical skin care ingredient. While it’s a type of alcohol, it doesn’t typically irritate or dry out skin.

Can I have a butylene glycol allergy?
It’s possible to have an allergy to nearly any ingredient, and butylene glycol is no different. There’s at least one report of an allergy to butylene glycol in the medical literature. But an allergic reaction caused by butylene glycol is uncommonTrusted Source.

Butylene glycol during pregnancy
Butylene glycol hasn’t been deeply studied in pregnant women.

A 1985 study of pregnant rats demonstrated that this ingredient had negative effects on the developing animals.

Anecdotally, some people recommend staying away from all glycol and petroleum products during pregnancy. Speak with a doctor about these products if you’re concerned.

Butylene glycol vs. propylene glycol
Butylene glycol is similar to another chemical compound called propylene glycol. Propylene glycol is added to food products, cosmetics, and even de-icing agents, like antifreeze. All glycols are a type of alcohol, and butylene and propylene glycol have a similar molecular shape.

Propylene glycol isn’t used in the same way as butylene glycol. It’s more popular as an emulsifier, anti-caking agent, and texturizer in your food.

However, like butylene glycol, propylene glycol is considered mostly safe when ingested in small amounts or when included in skin care products.

Takeaway
Butylene glycol is a popular ingredient in cosmetics and skin care products that’s safe for most people to use. We aren’t sure how common it is to be allergic to this ingredient, but it appears to be quite rare.

Butylene glycol may help condition your hair and make your skin feel softer. Studies point to its relative safety.

It's no secret that the beauty community has a tendency to take part in "cancel culture" when it comes to ingredients that we used to love (or at the very least, be okay with) and, when backed by science, this is rightfully so—our skin, a permeable gateway to our bodies, is precious and should be treated with the utmost care. One ingredient largely being dropped from product formulas as a result of the backlash is propylene glycol, and alternative ingredients are rising to take its place. Enter: Butylene glycol, a slightly larger chemical compound, which is found to be far less irritating. 

With expert insight from Morgan Rabach, MD, a board-certified dermatologist and co-founder of LM Medical in NYC and cosmetic chemist Ron Robinson of BeautyStat.com, we take a further look into the pros and cons of butylene glycol to figure out why it's used as a substitute for propylene glycol. Keep reading to find out everything there is to know about the ingredient that’s becoming increasingly popular in your skincare.

BUTYLENE GLYCOL

TYPE OF INGREDIENT: Humectant, solvent, and emollient

MAIN BENEFITS: Retains moisture, dissolves ingredients, and improves application.

WHO SHOULD USE IT: In general, anyone looking for a way to effectively moisturize their skin.

HOW OFTEN CAN YOU USE IT: Butylene glycol is safe for daily use for those who do not have an allergy to it or very sensitive skin.

WORKS WELL WITH: As a solvent, butylene glycol works well with ingredients that are not water-soluble and are difficult to dissolve.

DON'T USE WITH: Butylene glycol works well with most, if not all, ingredients.

What Is Butylene Glycol?
Butylene glycol is an organic alcohol derived from petroleum and is water-soluble. For cosmetic purposes, it comes in a liquid form and is found in countless skincare products such as cleansers, moisturizers, and masks, as well as makeup and haircare products. Butylene glycol has many different roles in skincare formulations (it's a humectant, solvent, and emollient) and is used as an alternative to the more commonly known controversial ingredient propylene glycol.

Benefits of Butylene Glycol for Skin
As a multifunctional ingredient in cosmetics, butylene glycol does a little bit of everything:

Attracts water: Robinson says butylene glycol is a humectant, which means it binds water and pulls in hydration to the outer layer of the skin.
Enhances penetration: By breaking down hard-to-dissolve active ingredients, butylene glycol improves penetration, which, as a result, helps the product perform more effectively.
Conditions and smooths: In addition to being a humectant, butylene glycol can also function as an emollient by creating a barrier on the skin, which prevents water loss and softens and conditions.

Butylene Glycol vs. Propylene Glycol
Since both of these ingredients are derived from petroleum products, available in the form of a colorless liquid, and used in product formulations for the same reasons, it's easy to get them confused. According to Robinson, butylene glycol and propylene glycol are in the same class of compounds and function similarly as well. However, Robinson says unlike butylene glycol, propylene glycol is considered to be much more irritating to consumers. In fact, propylene glycol was even named the American Contact Dermatitis Society's Allergen of the Year in 2018. 

For that reason, he says many brands have removed it from their formulas and turned to alternatives, such as butylene glycol, instead.

What you've heard about both ingredients being used in antifreeze is true, but neither is considered to be toxic (unlike another closely related ingredient that is also used in antifreeze called ethylene glycol—this ingredient is considered to be harmful and should definitely be avoided). Despite concerns and skepticism around butylene and propylene glycol, the EWG rates propylene glycol at 3 out of 10 (10 being the most hazardous) on their “danger scale” and butylene glycol at the lowest possible hazard rating: 1.

Side Effects of Butylene Glycol
It's important to note that just because an ingredient is derived from petroleum doesn't automatically make it dangerous to use. In its final chemical structure form, butylene glycol is considered safe for cosmetic use. Studies show that butylene glycol is an ingredient with low-levels of irritation, and the occurrence of allergic contact dermatitis is rare, although still a possibility. It can be irritating to people with very sensitive skin, and these skin types should avoid this ingredient if it leads to allergic rashes, according to Rabach and Robinson. If you do experience irritation or an itchy rash, discontinue use of the product and consult a physician. With formal patch testing, your dermatologist or allergist can determine if butylene glycol is the cause of your reaction.

How to Use It
Because butylene glycol is such a versatile ingredient and is found in so many products, there isn’t one certain way to apply it. In general, Rabach says butylene glycol is safe for daily use. As far as when to use products containing the ingredient, how often to use it, or how much should be used, consult your dermatologist or follow the directions specified on the product label.
One of the common reader requests I get is for “toxic” ingredient breakdowns, so today I’m looking at two ingredients that are commonly on “avoid” lists: propylene and butylene glycol.

WHAT ARE PROPYLENE AND BUTYLENE GLYCOL, AND ARE THEY SAFE?

Affiliate Disclosure: I receive a small commission for purchases made via affiliate links.

One of the common reader requests I get is for “toxic” ingredient breakdowns, so today I’m looking at two ingredients that are commonly on “avoid” lists: propylene and butylene glycol.

What are propylene and butylene glycol, and are they safe?

WHAT ARE PROPYLENE AND BUTYLENE GLYCOL?
Glycols in chemistry are ingredients that contain two OH (alcohol) groups. Propylene glycol contains 3 carbon atoms, while butylene glycol is a little larger and contains 4 carbon atoms. In glycols, the alcohol groups are attached to different carbons.

Confusingly, the names “propylene glycol” and “butylene glycol” can refer to several slightly different substances, since there are a few choices of carbon atoms for the OH groups to be attached to.

Propylene glycol usually refers to propane-1,2-diol (formerly known as 1,2-propanediol). The less commonly used propane-1,3-diol is also sometimes called propylene glycol, but usually in cosmetics it’s called “propanediol”. Propanediol is become more popular since propylene glycol’s been on all these watchlists.

What are propylene and butylene glycol, and are they safe?

It’s a similar story for butylene glycol. “Butylene glycol ” usually means butane-1,3-diol, but sometimes it’s also used to refer to the related butane-2,3-diol.

What are propylene and butylene glycol, and are they safe?

WHAT DO PROPYLENE AND BUTYLENE GLYCOL DO IN PRODUCTS?
Alcohol (OH) groups on ingredients usually make them good humectant moisturisers that can hold onto water and keep your skin or hair hydrated. For example, glycerin has almost the same structure as propylene glycol, but with an additional alcohol group. Propylene and butylene glycol are both humectant moisturisers.

Propylene and butylene glycol are also commonly used in products as solvents. They’re good at dissolving ingredients that aren’t very water-soluble. This means you end up with a more effective product since dissolved ingredients can spread out on your skin better and penetrate. Additionally, they can have antimicrobial effects and boost the effectiveness of preservatives.

Propylene glycol is a bit more common in products than butylene glycol. Both ingredients are commonly used in a ton of products, such as serums, moisturisers, toothpaste, shampoos and cleansers. They’re often also the main ingredients (after water) in sheet masks. They have a slightly slimy, goopy feel.

You’ll also find propylene glycol used as antifreeze, and in foods (it gets metabolised into lactic acid after you eat it). A few skin conditions can also be treated with propylene glycol, including seborrheic dermatitis and ichthyosis.

WHAT’S WRONG WITH PROPYLENE AND BUTYLENE GLYCOL?
There are a whole bunch of reasons why people tell you to avoid propylene and butylene glycol – let’s take a look at them.

“THEY’RE PETROLEUM-DERIVED”
The word “petroleum” is pretty scary for most people, since it makes you think of oil spills and toxic waste. But a lot of non-scary chemicals can be derived from petroleum too – for example, almost all plastics are made from petroleum. Where something comes from doesn’t tell you much about its toxicity.

“THEY’RE USED AS ANTI-FREEZE”
An anti-freeze is a substance that decreases the freezing point of water. The “scary” anti-freeze that causes poisoning is ethylene glycol, which is much like propylene and butylene glycol, but with only 2 carbons.

What are propylene and butylene glycol, and are they safe?

The three substances are similar in lots of ways, since they all have two OH groups: they’re all colourless liquids and work well as solvents, and they all work as anti-freezes. But a slightly longer or shorter carbon chain can make a big difference in terms of toxicity. 10 mL of ethanol (e.g. in the form of a shot of tequila) is quite fun and enjoyable for most people, but if you take off a carbon you get methanol, which is super toxic – 10 mL can make you go blind.

Same deal with the glycols – ethylene glycol is far more toxic than propylene and butylene glycol.

“THEY’RE SO DANGEROUS WORKERS NEED LOTS OF PROTECTION TO HANDLE THEM”
A few places warn that workers need to wear special equipment when handling these chemicals. These warnings come from the MSDS (material safety data sheets), which list the precautions for handling the raw material. But these warnings need to capture the worst case scenarios, and are for very large, highly concentrated amounts of the substance.

The MSDS information sounds scary even for otherwise safe substances. For example, sodium chloride (table salt) gets scary phrases like:

A self contained breathing apparatus should be used to avoid inhalation of the product
May affect behavior (muscle spasticity/contraction, somnolence), sense organs, metabolism, and cardiovascular system.
May cause adverse reproductive effects and birth defects in animals, particularly rats and mice (fetotoxicity, abortion, musculoskeletal abnormalities, and maternal effects (effects on ovaries, fallopian tubes)

“THEY CAN CORRODE STAINLESS STEEL CONTAINERS – IMAGINE WHAT THEY DO TO YOUR FACE!”
The MSDS also says that the glycols can corrode steel containers, which has led some people to say that “if they can corrode steel, imagine what they can do to your skin!” Luckily our skin isn’t steel… since water also corrodes steel.

“THEY’RE PENETRATION ENHANCERS”
Since propylene and butylene glycol are penetration enhancers that can help other ingredients enter your skin, many “toxic ingredient” lists say that they’ll increase penetration of other toxic ingredients into the bloodstream. This is technically true, but:

this means they’ll also help actives that you want in your skin penetrate, and
a lot of really unexciting things are also penetration enhancers, like water on your skin from cleansing.
“THEY CAN CAUSE IRRITATING AND ALLERGIC REACTIONS”
Here’s the actual legitimate issue with propylene and butylene glycol: in high concentrations, they can be irritating, and very rarely they can cause allergic reactions.

The Cosmetic Ingredient Review, who investigate cosmetic ingredients, have found that both propylene glycol and butylene glycol are safe when used in products that are designed to be non-irritating – in general, this means that propylene glycol can be used in products at up to 50% concentration (although most products will contain less than 20%), while butylene glycol can be used pure without many problems.

Propylene glycol is a bit more irritating than butylene glycol. Unsurprisingly, irritation with propylene glycol has been found to be worse when the product’s applied and then covered, and on broken skin as well.

It’s also possible to have a true allergy to propylene and butylene glycol, where your immune system gets triggered by them, but it seems to be extremely rare. Being allergic to propylene glycol doesn’t necessarily mean you’ll be allergic to butylene glycol.

ARE PROPYLENE AND BUTYLENE GLYCOL WORTH WORRYING ABOUT?
Even the EWG, which usually is pretty scaremongery and chemophobic, only rates propylene glycol at 3 on their “danger scale” and butylene glycol at 1.

If you’re sensitive to propylene or butylene glycol, you’ll notice that products with large quantities might make your skin itchy and irritated, and you’ll want to avoid those. But otherwise, they’re very safe ingredients.

butylene glycol
Rating: GOOD
Categories: Texture Enhancer
Commonly-used ingredient that has multiple functions in cosmetics, including as a texture enhancer. It’s similar to propylene glycol, but has a lighter texture.

The Cosmetic Ingredient Review board has evaluated several toxicology tests and other research concerning butylene glycol and has determined it is safe as used in cosmetics products. The U.S. Food and Drug Administration (FDA) has even determined that butylene glycol is safe as a food additive.

Butylene Glycol

What Is Butylene Glycol?
Butylene Glycol, Hexylene Glycol, Ethoxydiglycol and Dipropylene Glycol are clear, practically colorless, liquids. In cosmetics and personal care products, these ingredients are used in the formulation of hair and bath products, eye and facial makeup, fragrances, personal cleanliness products, and shaving and skin care products.

Why is Butylene Glycol used in cosmetics and personal care products?
Butylene Glycol, Hexylene Glycol, Ethoxydiglycol and Dipropylene Glycol are used as solvents and viscosity decreasing agents in cosmtics and personal care products.

Scientific Facts: 
Butylene Glycol, or 1,3-Butanediol, dissolves most essential oils and synthetic flavoring substances. Butylene Glycol, Hexylene Glycol, Ethoxydiglycol and Dipropylene Glycol are glycols or glycol ethers. Glycols are a class of alcohols that contain two hydroxyl groups which are also called a diols.