Toxic Timeout Ingredient Focus: Sodium Hydroxide

WHAT IS IT? Also known as caustic soda or lye, sodium hydroxide is a highly caustic, toxic and reactive inorganic base. It’s a powerful alkali used in industry for cleaning drains and pipe lines and is also used in oven cleaners. It is used a pH adjuster and denaturant commonly found in toothpastes, skin care such as moisturizers and facial cleansers, bath products, fragrances, foot powders, hair dyes and colors, makeup, nail products, personal cleanliness products, shampoos, shaving products, depilatories, skin care products and suntan products!

HEALTH RISK: In large doses, sodium hydroxide can cause chemical burns, permanent injury and scarring. It is classed as a poison to humans and animals. Cumulative or prolonged contact with skin can cause serious irritation, has a destructive effect upon tissue and skin cells and is known to aggravate pre-existing skin disorders. Make sure it’s not in any of your skincare!

WHAT TO DO: Watch labels for all three possibly-listed names: caustic soda, lye or sodium hydroxide. When possible stick to simple products with as few ingredients as possible!

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  1. it is my understanding that inorder to create soap, sodium hydroxide / lye / caustic soda was a necessary ingredient, but that it basically disappears once the soaping process is complete and so is not a concern specifically with soap. and sodium hydroxide has to be included in the ingredients list because it was used in the process. this is just what i have read / been told in the past…any insight would be much appreciated!

    danielle | 11.06.2012 | Reply
  2. Where are the alternatives listed?

    Danielle | 12.13.2012 | Reply
    • Hi Danielle, check out the link to ‘oven cleaners’ for a diy at-home idea for avoiding toxic oven cleaners! Thanks for your comment!

      The Chalkboard | 12.13.2012 | Reply
  3. Seriously? I wouldn’t want sand it my eyes, but that doesn’t mean it’s toxic. Anything not handled properly is toxic — even water.

    People eat food made with sodium hydroxide (e.g. pretzel, lukefish, century egg, etc.)

    Because it’s in the ingredients list doesn’t mean it’s in the product. This is where chemistry comes into play. How would you make soap without it? You couldn’t. Lye + Fat = Soap + Glycerin. No lye, no soap.

    Becky | 09.23.2013 | Reply
  4. It is not possible to make a natural bar of soap from start to finish without sodium hydroxide. You can if you wish make melt and pour but that is not a proper hand made bar of natural soap. So if you can give me a recipe for making a natural soap bar from start to finish without using sodium hydroxide please do.

    cynthia | 09.27.2013 | Reply
  5. I agree with Cynthia. You can’t make soap without lye. If you put lye on your skin of course it will burn. Once you mix it with various oils a chemical reaction takes place that creates soap. Kind of like mixing hydrogen and oxygen (umm, H2O, water). Separately they are different, together makes a product we cannot live without.

    Rose | 02.25.2014 | Reply
  6. Sodium hydroxide isn’t necessarily bad, it depends on how it’s used. When it is used to make soap, it chemically reacts with the fats until the fats are fully saponified. If there isn’t ebough fat, there will some left over sodium hydroxide in the soap, which may cause skin burns. But it is possible to make soap without it. Not without lye, but without sodium hydroxide. Potassium hydroxide is another type of lye, and it is easily obtained from hardwood ashes and water. That is the original all natural method for soap, and potassium hydroxide actually creates a soap that’s superior to the sodium hydroxide version. It lathers better, rinses cleaner, and seems gentler on the skin.
    On another note, literally everything is toxic, it’s all about quantity. Yes, we need oxygen, but if you were to breathe in straight oxygen for too long, you’d die. Arsenic is a known poison, but there are trace amounts in your body at all times, because it is a naturally occurring substance (found in certain fruit seeds/pits, among other places), it only becomes detrimental at high levels that exceed your bodies threshold for eliminating it. Ammonia is toxic, but your body creates it when it digests and tears apart certain amino acids from the proteins in our food.
    If you really want to know what chemical to be on the lookout for, Google dihydrous monoxide(DHMO) It’s literally everywhere. It’s in our lakes and streams, in our food, in our air, it comes out of our taps, it’s in our milk, shampoo, and cleaning products. It has been found in 100% of cancerous tumors, in it’s gaseous form it’s known to cause severe burns, aspiration or inhalation can be deadly.
    Dihydrous monoxide is water. Plain old H2O. But if you tell people the skewed facts without telling them that DHMO is just pure water, people invariably freak out, panic, and start calling on lawmakers to outlaw it. Several lawmakers have even fallen for the prank, and started the legal process to banning the substance, before they were informed. A DJ, on the radio, once told his listeners that there was DHMO in the water supply, coming out of their faucets right now. There was an absolute panic!
    I agree that we need to be safe and smart about what we put on and in our bodies, but that means making smart and informed decisions. Blindly believing people who claim something is unsafe is just as bad as blindly believing the big business assurances of safety. Do real research into the chemistry behind this stuff.

    Crystal | 03.27.2015 | Reply
  7. so what’s the alternative?

  8. My wife and I own a company that makes and sells natural, organic skin care products. Lye soap is what started us off. I challenge the writers of this blog on their “expert” knowledge. Glycerin in its raw form and bar soaps are both made using lye. SLS,SLC, SLES are made using coconut oil and sulfuric acid. (these three have their own issues and not necessarily deemed “good”) and Castile liquid soaps are made using Potassium Hydroxide…unless you are talking about rubbing your body with slices of orange or lemon or using soap nuts – I would love to know the alternatives that are talked about but not listed here.

    Kelly Taylor-Faye | 08.11.2016 | Reply
  9. I am a soap maker and all true soap is made with lye (sodium hydroxide or potassium hydroxide). Even glycerin soap & melt & pour soap bases are made with lye. When lye (sodium/potassium hydroxide) is mixed with oils or fats, a transformation takes place (called saponification) & the finished product is SOAP….no lye is present anymore… Please educate yourself about the topic you are writing about before publishing disinformation on the web.

    Jennifer Herrington | 04.20.2018 | Reply
  10. In my “full in Nature experiences” I only use wood ashes and water to wash literally anything, from skin, to clothes and pots…passing dry ashes on surfaces before and then rinsing with water. So great the result! Just with no parfume…not even smell of smocked actually…it’s not in a bar, but, what other form could ashes take in order to be used “as soup”(if I’m not doing something wrong..hehe….)

    Letizia Guarise | 04.23.2021 | Reply

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