Even if you aren’t familiar with the term sodium hydroxide, you might know this chemical compound by one of its other names: lye or caustic soda.
Sodium hydroxide isn’t at all hard to find. This common ingredient, which consists of solid white, odorless crystals, features in a vast array of skin care products. Tetrahydrofuran 99.9%
Of course, as one of its names suggests, it’s caustic. In other words, it can cause chemical burns, in your eyes or on your skin.
Naturally, this has raised some eyebrows about its use in the beauty and skin care world. So, just how safe is it?
Sodium hydroxide is overall considered safe for general use — but only in small amounts, at lower concentrations.
At higher concentrations, sodium hydroxide is unsafe. It can cause chemical burns, as noted above, along with hives and holes in your skin. It’s also very harmful if you eat it or inhale its fumes.
But here’s the good news: Skin care and beauty products only contain this ingredient in small amounts, so you’re unlikely to experience a chemical burn from any skin care products you’ve purchased. You also don’t need to worry about toxic fumes from your skin care products.
In other words, there’s no need to do a clean sweep of your cabinets or completely overhaul your skin care routine.
Beauty and skin care products, like soap, face wash, and body cream or lotion, regularly use sodium hydroxide.
Other common products with sodium hydroxide include:
Name a skin care product, and there’s a good chance you’ll find sodium hydroxide in it — in small amounts, that is.
You’ll also find it in plenty of cleaning products, including laundry detergent, drain cleaner, and oven cleaner. These substances, of course, are the ones you’d never dream of putting on your face.
You might wonder, if this ingredient is potentially unsafe, why manufacturers toss it into so many skin care products.
Well, sodium hydroxide shows up in so many products, because it has a specific job: to help balance and maintain the pH of skin care products.
It can do this because sodium hydroxide is highly alkaline. In fact, it clocks in at 14 on the pH scale, which ranges from 0 (very acidic) to 14 (alkaline, or very basic). In basic terms, sodium hydroxide is the most basic you can get.
This matters, if you’re wondering, because your skin has a more acidic pH. Skin generally falls somewhere between a 4 and 7 on the scale.
It’s important to maintain your skin’s acid mantle — this natural level of acidity — to keep moisture in and help protect your skin from various damaging elements, from bacteria and viruses to environmental toxins and pollutants.
The acid mantle can also help shield your skin from harsh weather and ultraviolet (UV) damage — though sunscreen is still an absolute must.
That’s why you want your skin’s pH to stay balanced. With an unbalanced skin pH, you could have a higher chance of:
Sodium hydroxide also plays another important role in the creation of skin care products during saponification, a chemical reaction that transforms fats and oils into a smooth, well-mixed soap.
Again, experts consider sodium hydroxide generally safe in beauty and skin care products, since the products contain this ingredient in small amounts, at low concentrations.
That said, certain ingredients don’t work well for everyone. If you have sensitive skin, you might be even more likely to experience an unwanted reaction when using products that contain sodium hydroxide.
Performing a patch test before using any new-to-you skin care product (whether it includes sodium hydroxide or not) is always a good idea.
Here’s how to do a patch test:
Just to be absolutely clear: It’s not safe to apply pure sodium hydroxide to your skin, in any amount or concentration. Sodium hydroxide can cause chemical burns and severe skin damage.
If you’ve ever checked the back label of a bottle of drain or oven cleaner, you may have noticed a warning about wearing gloves.
Even if you plan to be very careful, never skip the gloves when handling these cleaners. Gloves protect your hands from severe side effects, like chemical burns and holes in your skin, along with more minor skin concerns, like itching and inflammation.
If you experience a serve allergic or adverse reaction, get immediate medical attention.
You’ll also want to get immediate medical attention if you accidentally get sodium hydroxide in your eyes, since you could experience vision loss as a result.
Avoid putting any product containing sodium hydroxide in your mouth. Accidental ingestion of sodium hydroxide can cause:
Sodium hydroxide is a pH balancer used in a wide range of beauty and skin care items, like cleansers, soaps, makeup, and creams or lotions.
In its pure form, sodium hydroxide is extremely harmful, but beauty and skin care products don’t contain much sodium hydroxide, so they’re safe to use.
That said, if you have sensitive skin, it may be worth checking the ingredient labels before purchasing new products and steering clear of any products that contain sodium hydroxide.
Breanna Mona is a writer based in Cleveland, Ohio. She holds a master’s degree in media and journalism and writes about health, lifestyle, and entertainment.
Last medically reviewed on February 16, 2022
Our experts continually monitor the health and wellness space, and we update our articles when new information becomes available.
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