No Lyes, Please: is Sodium Hydroxide Safe in Skin Care?

Curated by Claudia Shannon / Research Scientist / ishonest

Here’s the scoop on why sodium hydroxide shouldn’t actually burn your face off when used in skin care products.

What is sodium hydroxide?

Sodium hydroxide (aka lye or caustic soda) is a solid white compound that absorbs water from the air. It’s alkaline AF with a pH of 14, which helps it balance the pH of skin care products when used in teeny tiny amounts. (Psst: think of alkaline, aka basic, as the opposite of acidic).

ishonest No.233 - Pigmentation & Blemishes

No.233 - Pigmentation & Blemishes

It’s also the key ingredient in helping fats and oils become one in soaps and cleansers. It’s also used in facial and body care products.

Sodium hydroxide’s basic properties also make it a solid addition to cleaning products like oven cleaners, drain cleaners, detergents, paper, and aluminum.

So, is sodium hydroxide safe for skin?

Concentrated amounts of sodium hydroxide are extremely caustic, which means it’s corrosive and can cause chemical burns to the skin and eyes. It’s also very dangerous if consumed or if you breathe in its fumes.

Real talk. This makes sodium hydroxide sound pretty darn scary. But when added to skin care products, sodium hydroxide is used in low doses that are generally completely used up in the reaction process. So, the harsh vibes are gone by the time a product touches your skin.

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P.S. Sodium hydroxide is generally recognized as safe as a food ingredient by the FDA. But take note, this is mostly for produce washes, not actual foods.

How does sodium hydroxide work in skin care products?

Sodium hydroxide can saponify oils. That means it helps the oils and fats lather and foam into a soap. Without it, your soap would be a big mess of various oils and fats that aren’t unified into one product.

It’s also used in small amounts to establish and maintain the pH of a product. Skin tends to be on the acidic side and usually ranges between 4 and 7. Maintaining this acidity (aka the “acid mantle”) provides a layer of protection against environmental factors like allergens, pollutants, and bacteria. If your skin care’s pH is out of its typical range, you can disrupt your skin’s acidic protection, which might increase your risk of premature aging too.

In the beauty world, you’ll mostly find sodium hydroxide in:

  • makeup
  • hair dye
  • nail polish
  • face wash
  • body cream
  • nail polish remover

Sodium hydroxide side effects on skin

ishonest No.231 - Pigmentation & Blemishes

No.231 - Pigmentation & Blemishes

You should NEVER put pure sodium hydroxide on your skin. It can cause skin symptoms like mild to severe chemical burns, or holes in the skin and underlying tissues. Even concentrated amounts used in oven and drain cleaners can damage your skin, so get those gloves on.

Products that contain or are made with sodium hydroxide might cause:

  • hives
  • itching
  • redness or discoloration
  • irritation
  • flaking skin
  • increased sensitivity

Using skin care with small concentrations of sodium hydroxide is usually WAY safer. But you may still need to be careful, especially if you have sensitive skin.


Sodium hydroxide is an alkaline compound that’s used to balance pH and saponify fats and oils. You’ll find it in lots of skin care products like soaps, makeup, cleansers, and lotions.

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In high concentrations, it’s very caustic and will burn your skin. But it’s used in small amounts in skin care products that tend to get totally used up in the reaction process. So, a lot of it doesn’t actually make it to the final product.

Pure sodium hydroxide can be 10/10 dangerous. If ingested, it can trigger lung inflammation, throat swelling, intense abdominal pain, severe change in blood pH, and difficulty breathing. It can also lead to vision loss if it gets in your eyes.

P.S. Always talk with a dermatologist before making any major changes to your skin care routine. This is extra important if you have a condition like eczema, psoriasis, cystic acne, or rosacea.

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