Ingredient Watch List: Cyclotetrasiloxane, the Hair Conditioner That May Harm Our Waterways


You know how your hair feels soft and smooth after you put conditioner in it? You may think that's because your conditioner gives the hair what it needs to be healthy. Unfortunately, in most cases, that's not it.

Many conditioners contain chemicals that coat the hair strand, making it act like it's healthy. In reality, it's in the same condition as before with a few chemicals putting on a show for awhile. Have no doubt—when the chemicals wash off, your hair will go back to being dry, frizzy, and dull.

How can you tell if your conditioner is truly helping your hair or only covering it up? Like everything, it depends on the ingredients. If you read “cyclotetrasiloxane” in the list, you've probably you've got a more chemical formula on your hands.

What is Cyclotetrasiloxane?

Also called “octamethylcyclotetrasiloxane,” this ingredient is one of many “siloxanes,” which are made up of silicon, oxygen, and alkane. (Silicon is a nonmetallic element abundant on Earth.)  In other words, it's a silicone-based ingredient used in cosmetics, deodorant, defoamers, lubricants, and soaps to soften, smooth, and moisten. Siloxanes make hair products dry more quickly and deodorant creams slide on more easily.

Is it Safe?

Like so many of the chemicals in personal care products, this one has been generally considered safe—particularly in rinse-off products like conditioners. But research from Canada in 2008 raised concerns about cyclotetrasiloxane (also called D4) and its sister chemical, “cyclopentasiloxane” (also called D5).

According to the Environmental Working Group (EWG), the government in Canada declared these two chemicals potentially toxic around January 2009. At that time, the government had serious concerns about the hazards of the chemicals, and prioritized them for action to ensure exposures were safe for people and the environment. Environment Canada and Health Canada proposed adding both to the list of toxic substances, and to develop regulations to limit the quantity or concentration of D4 and D5 in personal care products.

According to Environment Canada, D4 and D5 are toxic, persistent, and have the potential to bioaccumulate in aquatic organisms. The European Union also classifies D4 as an endocrine (hormone) disruptor, based on evidence that it interferes with human hormone function, and may impair human fertility.

What are the Concerns?

California has also done some looking into this ingredient, and it seems they are also concerned. According to the Office of Environmental Health Hazard Assessment (OEHHA)—a specialized department within the California Environmental Protection Agency that evaluates health risks from environmental contaminants—cyclosioxanes like D4 and D5 have “long half-lives in people. The weak estrogenic activity of D4, in combination with its long half-life, poses potential concerns for exposed individuals.”

In other words, one exposure to the chemical may not hurt you, but we use this ingredient every day in our homes, in our hair, and in our bathtubs, and so far, we don't know what that means for our health.

What about D5? The OEHHA states, “While studies have not shown D5 to be estrogenic, it nonetheless increased uterine tumors in animal studies. In addition, there are potential concerns related to effects of D5 on the neurotransmitter dopamine and the hormone prolactin.” In other words, this chemical could be affecting our brains and nervous systems with repeated exposures, but we need more studies to be sure.

What About the Environment?

On top of the health concerns, these chemicals have been found to resist breakdown in the environment. The OEHHA has detected D4 in wastewater streams. “Certain siloxanes are persistent in the environment,” they stated, “resisting oxidation, reduction, and photodegradation.”

A more recent announcement by the government of Canada concluded that D5 is not harmful to the environment, after a review of all available scientific information. Apparently the word on D4 is still out.

What to Do?

On the whole, these siloxanes are probably not going to hurt you. Most are in rinse-off products, so as long as you're not using them in the bath (where you soak), you're probably not exposed long enough to cause significant health problems.

The danger to our waterways, however, may be more serious. We are still awaiting more tests to determine just how much damage D4 may do in the long run.

Of course, my feelings as always are to avoid the iffy chemicals and go with more natural, nourishing products. Why pretend your hair is shiny and healthy when you can get the real thing with olive oil or coconut oil? There are several organic companies out there, as well, making safer products that you won't have to worry about, or you can try some of the many homemade conditioner recipes you can find on the Internet. I say it's worth a little investigation!

Do you have siloxanes in your conditioners and other personal care products? Please share.

* * *

“Cyclomethicone and ingredients ending in ‘siloxane',”,—siloxanes/.

Environment Canada and Health Canada. “Screening Assessment for the Challenge
Octamethylcyclotetrasiloxane (D4).” November 2008.

Environment Canada and Health Canada. Screening Assessment for the Challenge: Decamethylcyclopentasiloxane (D5). November 2008.

DHI Water and Environment. Study on Enhancing the Endocrine Disrupter Priority List with a Focus on Low Production Volume Chemicals. Revised Report to DG Environment. Hersholm, Denmark: DHI, 2007.

Diane MacEachern, “Newly Identified Toxic Chemical is Common in Cosmetics,”, February 5, 2009,

“EWG: Lipstick Chemicals Declared Toxic by Canadian Gov't,”, January 31, 2009,

Michael D. Shaw, “Some Good News Regarding Siloxane D5—And Why You Should Care,” Marhc 19, 2012,

comments (55 and counting)


Reader Interactions


  1. says

    Marc Anthony curl lotion. I’ve been going without silicones in my hair for years. This one had the cyclopentasiloxane further down in the list, so I thought it might work out. But researching brought me to this article. Thank you for all the information, and this is not in my bag anymore. Now I have to go research my lotions too!!

  2. Lida says

    This ingredient is usually the first one in about 95% of foundations and conclears. I have been doing research by reading ingredients in every cruelty free brand on I found a few cruelty free brands that don’t use cyclopentasiloxane in their formula: Hourglass vanish the stick foundation, Ilia true skin serum foundation, coverfx natural finish foundation, lawless woke up like this liquid foundation, and milk makeup blur liquid matte foundation. I haven’t looked into powder formulas yet. I recently bought a Tarte clay foundation the one in the squeeze tube , from Ulta and cyclopentasiloxane is the second ingredient after water, I was highly disappointed because I usually love Tarte, and I used the foundation before. So I’m taking it back to the store and I’m going to stop by Sephora and test out the ones listed, except for the lawless because it is not in stock for a 100 mile radius from Los Angeles. I will also be looking into conclears that don’t carry cyclopentasiloxane. For me personally, I wouldn’t want an ingredient that may considered toxic to my endocrine system to be sitting on my face for 7-9 hours a day on my face everyday. We must be informed shoppers.

  3. Tracy says

    Organic Nourishing Coconut Hydratng Oil Mist (for hair). I’ve started looking more carefully at ingredient lists and notice that almost every kind of conditioner (rinse out and leave in) is basically glycerin, ceateryl alcohol, and different kinds of silicones. So frustrating! This product is nice and lightweight and seemed good for curly hair. Not going to use it anymore!

  4. Samantha says

    Tree hut shea moisturizing body lotion, obviously intended for long exposure. Oi vey! It’s the eighth ingredient but after that are a whole bunch more I can’t pronounce, and dimethicone before it that I also found on this site, thank you for this info!

  5. Ashley Rodriguez says

    Suave Professionals Smoothing Hair Serum, Keratin Infusion.

    I was wondering how they could afford to sell any sort of keratin treatment for under $5 and make a profit.

    First ingredient? Cyclopentasiloxane.

    Thank you for the warning! It’s in the trash now.

  6. Nadia says

    Garnier Loving Blends hair serum (not to be washed out). First ingredient: Cyclopentasiloxane. Just like someone else commented, this name made me look for the safety of this ingredient before reading the rest of the ingredients. Normally, I only buy organic or 100% natural cosmetics, but this one was on sale and the ‘Honey Gold Bees Balm’ sounded so nice… Wish I could return the product now 🙁

  7. Dana says

    So disappointed to find out this is the first ingredient in the aromatherapy massage oil from bath and body works I just picked up. I didn’t know anything about this stuff but when I read the back of the bottle I didn’t even get past the first ingredient before I decided it was probably a good idea to do some research. Funny thing is, I wasn’t even going to buy it. It was 30 minutes to close and I was cashing out and the girl convinced me to buy another item because I’d get 2 more free and pay the same amount anyways with the coupons I had. Normally I’m a little more informed and read before I buy but I felt rushed. It smells so good too =(

  8. Teresa Dixon says

    My face is tingling and my mouth is jumping around my lips. I am wondering if I need to report this to someone. I just used Christie Brinkley Authentic Skin Care cream this morning and last night but I forgot to rinse it off before I went to bed and all I did was wash it off with water this morning and put it right back on for another 17 hours now and my whole face is now tingling. I am getting some kind of reaction to the chemicals used in it. So I looked up the first word that I couldn’t pronounce and bingo I figured it was the cyclopentasiloxane, that could be doing it! What can I do? As soon as I get the chance I am going to scrub my face and never use this chemical again! I thought it was skin care not skin scare!

  9. Pauline says

    I was given a trial on a cream for wrinkles and healthier skn. I was told that the ingredients were all natual. It hasthis cyclotetrasiloane in it. I have just read this artical. So its used in conditioners etc. Not to harmful cause you RINCE your hair of it after a few minutes. When you use it on your face. It is left on. How toxic is it as yesterday my face was burning. And i was under the impresion that it was natural. The product is called neruim international. Made in usa

  10. Claudia Payne says

    Just found the first ingredient in Garnier Fructis miraculous oil is cyclotetrasiloxane … I might give the body shop coconut oil a go instead since it’s free of silicone and other nasties

  11. Natalie says

    As cause to wonder, I was curious what was in Kerastase Elixir old team oil . I work at a Kerastase salon and am exposed to these ingredients all day long everyday. I recently became very aware and I’m very excited to help educate my clients and steer them toward a more natural Direction where they’re not be polluting their beautiful bodies or our beautiful Earth. Thanks for doing your research this was an awesome article!

    • Annmarie Skin Care says

      Hi there,

      We wouldn’t suggest using it on your lips because it is on your skin and easier to for the chemical to get into your body by eating it.

  12. Bob says

    I have New Malibu Hemp Coconut Body Moisturizer, it contains Both the cyclotetrasioxane and cyclopentasioxane,, I’ve been experiencing dizzy spells Not sure it has anything to do with it But. I’m not using this again..

  13. theresa says

    Perfect Formula Daily Moisture for nails. First ingredient jojoba seed oil then cyclotetrasiloxane. Shouldn’t OIL be enough on its own? “Conditions nails to prevent brittleness”.
    Hormone disruptors may also be contributing to obesity epidemic.

    • Ashley Rodriguez says

      That last point is so prevalent. I wouldn’t be at all surprised if that were the case. I’m sure there have been studies. I’d like to check on that now.

  14. Clem says

    Cyclopentasiloxane is the second ingredient listed in Clinique’s Moisture Surge Intense Skin fortifying hydrator!!!!!

  15. Laura D Ramirez says

    I have recently purchased a polishing serum for my hair, to apply on my mid shaft to ends after every wash. I looked at the ingredients, and the first one happened to be cyclotetrasiloxane… So, I was curious about it and looked it up. After reading these informative paragraphs, I’m not sure if I should be convinced or concerned…

  16. Dyana says

    So Garnier Frutis Sleek and Shine Moroccan Sleek Oil Treatment has D5 as their first ingredient. It’s not conditioner so I didn’t rinse it out. I’m not recommending anyone to use this because it gives a false texture.

  17. Kathleen says

    A new product for crept skin has
    Cyclopentasiloxane in it. It I used everyday
    On the skin not a good thing
    People beware of hydra firm it has many other toxins in it also!
    Just getting started!

  18. Lola says

    Cyclopentasiloxane is the FIRST ingredient to the Renpure Argan Oil Treatment Micro Mist Spray from Target. The shampoo seems okay however. Renpure boasts being “pure”, even adding it to the name, had four potentially hazardous chemicals listed at the very beginning. Only the last ingredient was argan oil and fragrance. And it’s “proudly made in the USA”? Come on guys. Get your acts together

  19. Karen says

    My hair dresser and I have been using UNA Pure Gloss Polisher for years and she promotes this line in her Dominican Salon. Now that my daughter and I have decided to go “natural” I’m looking at the labels on everything. Low and behold this UNA Polisher’s first two ingredients are D4 & D5 – so disappointing. I had planned to start switching to natural oils like Jamaican Castor Oil, Avocado Oil. JoJoBa oil, Coconut Oil, and Olive Oil, but wanted to finish out the UNA polisher. Now i have to let it go; and it’s quite expensive. Glad I found this article!

  20. Julie says

    First ingredient in Dove deoderant that my 13 year old daughter uses. Anyone have a suggestion for a natural safe depderant that works?

    • Bridget says

      Try USDA Organic lemon juice. I cannot use baking soda because it causes huge rash. I heard about lemon juice n tried. Amazing. After time it lasts longer than chemical laden deodorants. Amazing!

  21. tobe halton says

    just came home with some”dermatologist formulated – antioxidant facial serum – for all skin types” from Trader Joe’s; the main ingredient (cyclopentasiloxane) was unfamiliar to me, but almost all of the others were the natural skin supplements and anti-oxidants i was looking for, so i bought it, planning to research cyclopentasiloxane when i got home. thank you very very much for your web site which has steered me away from this stuff!
    back to Trader Joe’s i go…
    best, tobe

  22. Karen widucj says

    I use Arbonne products on my face and hair, but they don’t make styling products because it’s near impossible to make them without using something artificial and ultimately unhealthy which is there goal (only use ingredients that are good for you). Remember that skin is your largest organ, weighing about 8 pounds in covering 18 square feet of your body. Within 15 seconds anything you put on your skin is absorbed into your bloodstream, so be careful what you put on it.

    • Robin says

      Cyclopentasiloxane is the second ingredient in the Arbonne Intensive Renewal Serum. Are you still using these products? If so, do you think this is a concern? I am in the beginning stages of research for new facial creams and cleansers.

  23. Snowy says

    I recently bought Agadir Argan Oil to give to friends and families and found these chemicals as first listings and decided to look them up. Oh I am so sad. i was thinking that I was getting mostly argan oil and do not want to pollute the water ways or adversely effect the aquatic animals. Does anyone know of an alternative product for argan oil hair treatment

    • Osca says

      Interesting, very interesting. ..I just bought One and Only Argan Oil..trying to save some dead president’s. ..Have bought the all natural brands before, but very costly.
      Now that I have investigated the ingredients in the off brand….its going back ASAP!!

  24. Fikiswa says

    Thank you for this, just bought Hydratinghair repair cream from Beauty Treats from the pharmacy andithas all these things, syclopentasiloxane, dimethicone,cyclotetrasiloxane,polyacrylamide ect. I will be returning it back tomorrow

  25. Alison says

    I fell for the marketing packaging again. 🙁 It said “Penetrating Oil for Dry and Coarse hair: Renewing Argan Oil of Morocco” (from Beauty Pure and Simple). It came out goopy like silicone so I checked, and yup, it’s a recipe of D4 and D5 with Argan oil added just before perfume and colorings.

  26. Isiris says

    For about a week I’ve been using Organix weightless coconut oil mist & it works beautifully but I just noticed it has cyclotetrasiloxane & cyclotetrasiloxane as the first 2 ingredients! What a shame. I was just told about Tropical Traditions products that don’t have nasty chemicals. Gonna try those.

  27. Teresa says

    I wish I had looked up the ingredients for the renewing Argan oil. I stopped using anything with silicone on my hair for over a year and I bought it because I heard great things about it. Silicone is just fake shine that adds residue to your hair. When you’re all about avoiding washing your hair this is a pain. I co wash and use coconut oil on my hair and nothing else and it’s been great but getting coconut oil on a bottle spray pump is rough so I bought this. I thought this would be great way to avoid wetting my curly super long hair.

  28. Helaine says

    I was given two tubes of Marc Anthony Strictly Curls and at first thought how lucky I was to receive them. Then I read the ingredients and realized that the product poses both health and environmental hazards. My tendency is to not waste anything and I considered giving it away. Do I dislike anyone enough to gift them poison? Never. I disposed of it at a local hazardous waste drive.

  29. Aubrey says

    Paul Mitchell skinny serum has this as well as cyclopentasiloxane, cyclotrisiloxane, and other garbage ingredients. My hormones have been awful for the past year. I won’t be using this ever again and I will be calling the company.

  30. BatiYah says

    IC’s Fantasia Hair Polisher Carrot Hair Growth Serum has D4 (Cyclotetrasiloxane) as the first ingredient. Bummer. It seems to work well. I’m not sure which ingredient/s help hair to grow faster, but no chances here. Good thing i haven’t used it for long. I’ll stick with Green Smoothies to strengthen my hair inside and out. Peace and Love.

  31. lisa Bradfield says

    MARY KAY eye makeup remover works so well I was curious to see what was in it. 2nd ingredient is cyclotetrasiloxane-.

    • Martina Elegant says

      That may be the reason why MK has the content info only on the boxes. I just bought argan oil of Morocco but cannot return it. Why don’t have they the real stuff?

  32. Suz L says

    Bought a product for hair at ULTA today- “Not Your Mother’s ” brand “lock luster oil treatment”. When I applied it to my dry hair it created so much static electricity ! Not the smoothing effect I was looking for. When I looked on the label on back it says it is “flammable until dry “! It has D4, D5 and c-12-15 Alkyl BenZoate as the first 3 ingredients. Now that I know about it, I will not be buying these products again?
    Also, made in the USA! Why are we putting flammable and extremely concerning toxins in any product for our bodies! We should be more responsible as producers of goods in this Country.
    I will be more discerning on my next ULTA shopping trip!

  33. Christa Shipman says

    I have been using Herbal Essences shampoo and conditioner and having no problem.
    Two days ago I started using a cheaper Suave conditioner and I got an itchy rash on my head. My mom noticed that the Suave conditioner has cyclopentasiloxane, and thought that might be the problem. I am glad I read this article: definitely won’t use that shampoo again!

  34. sunny says

    Ahhh I just used organix argan oil of marocco!!!
    Wish I had read up on this earlier. 🙁
    I’m careful with whats in my food but never gave other products much thought.
    Thank you for the info.

  35. Julie says

    The first 2 ingredients listed for the Organix Renewing Argan Oil of Morocco Weightless Healing Dry Oil product are Cyclotetrasiloxane and cyclopentasiloxane. Glad I found this article. As I just bought the product, I will be returning it.

  36. monica says

    so im ordering a wig- it contains d4 or d5 which ever i choose . is it safe for me to use? if its bad for the environment i can always wash it out side n give it a fresh rinse with filtered water using a bowl . idk = please tell me if its safe

    • admin says

      Knowledge is power Lisa, good for you for taking action when you found your products are dangerous. Thank you so much for sharing, make it a wonder-filled day

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