by John Moody | Affiliate links

When I was a kid, I was always intrigued by the boxes and bottles under grandma’s kitchen sink. One of those boxes that was prominently emblazoned with a Mr. Yuck sticker was “20 Mule Team Borax.” What a strange name, I thought as a kid (and still kind of do as an adult).

Just because Grandma used borax and she lived to be 95, does this mean it is safe? Is it a good choice for those trying to live in a responsible manner with regard to the environment? Or, is it like castile soap – green or not so green depending on what you buy.

Let’s find out!

What is Borax?

Borax has been known and used by humankind for centuries. It was first obtained from saline lakes in Kashmir and Tibet and refined in Europe.

While most people call it borax, its technical name is sodium borate. Basically, it is a salt of the element boron. Once processed, the solid form is a white crystal powder that dissolves easily in water.

Where does it come from? Under your feet, as it turns out!

Borax is mined from boron deposits found in many diverse places around the world – California, Turkey, Chile, Bolivia, Tibet, Romania. There is hardly a part of the world without it, although California produces about 50% of the world’s supply of commercial boron compounds. (1)

Chemical Names

Borax itself has many chemical formulas and names, including:

  • Anhydrous borax or sodium tetraborate (Na2B4O7)
  • Borax pentahydrate (Na2B4O7·5H2O)
  • Borax decahydrate (Na2B4O7·10H2O)

The difference between them is simply the water content! (2)


Most people are familiar with borax for its use in laundry or other cleaning purposes around their homes. Yet, it has many important applications across numerous industries.

Everything from the manufacturing of glass, to ceramics, even metallurgy uses it!

Since it is antiseptic, it is a popular ingredient in products used to whiten, disinfect, or deal with mold and mildew, like in baths and showers.

The compound also helps remove stains and cut grease. Hence, it is a key ingredient in many homemade laundry detergents.

Besides stain removal, it is a fairly good deodorizer to boot.

Practically speaking, borax has a wide range of uses and benefits around the home as well as in industry. (3,4)

Note that the WHO concluded that the use of borax and boric acid as food additives were unsafe back in the 1960s, however. (5)

Borax vs Boric Acid?

Let’s take a moment to ensure we are on the same page.

Borax, which is usually sodium tetraborate or sodium borate, is not boric acid!

These are very different, albeit closely related, chemicals.

Boric acid is far more dangerous and toxic than borax, especially when used as a pesticide.

Unfortunately, many of the studies on the safety of borax don’t clearly specify which was used and much of the data is lumped together or both were studied at the same time.

Hence, be careful when drawing conclusions unless you are quite sure which substance was actually studied. (6)

Is Borax Safe?

Borax is a known eye, skin, and lung irritant. If this makes you want to run for the hills, hold on. So are ground cinnamon and many other spices, vinegars, essential oils, and a host of other everyday substances including dust.

In fact, borax has the same Material Safety Data Sheet (MSDS) rating as things like baking soda, salt and similar commonly used compounds. (7)

Why does borax irritate the skin, lungs, and eyes? On top of the form, it is the pH. Borax is quite alkaline. If you remember your high school chemistry, pH runs anywhere from 0-14, with water being around 7, or neutral.

Anything much below 5.5 (acidic) or above 8.5 (alkaline or basic) will generally irritate the skin, eyes, and lungs. Borax comes in at 9.3! Baking soda comes in at 8.4, which is why some people are and some aren’t sensitive to it – it is right on the line pH-wise and some people tolerate it better than others.