Boric acid is a mild antiseptic as well as a mild acid that inhibits the growth of microorganisms on the external surfaces of the body. It is commonly used in contact lens solutions, eye disinfectants, vaginal remedies, baby powder, anti-aging preparations and similar external applications.

Boric acid and other borates are increasingly being used in over-the-counter nutritional supplements as a source of boron. It is thought that boron has a potential therapeutic value in promoting bone and joint health as well as having a limiting effect on arthritis symptoms. It is important to note that the health effects of boric acid and boron-based
supplements are based on very new studies and/or are based solely on the claims of the manufacturers’ of the supplements. It should not be implied that boric acid should be directly ingested as a supplement or for any other reason.

Boric acid inhibits the release of combustible gases from burning cellulosic materials, such as cotton, wood, and paper-based products. Boric acid also releases chemically bonded water to further reduce combustion. A carbon char is formed that further inhibits combustion. Futons, mattresses, upholstered furniture, insulation, and gypsum board are common consumer items that use boric acid as a flame retardant. Plastics, textiles, specialty coatings, and other industrial products also contain boric acid to strengthen their ability to withstand exposure to flames.

Heat resistant, borosilicate, and other specialty glasses rely on boric acid and other similar borates to increase the
chemical and temperature resistance of the glass. Halogen light bulbs, ovenware, microwavable glassware, laboratory glassware, and many everyday glass items are enhanced by the addition of boric acid. Boric acid also aids in the fiberization process of fiberglass, which is used in fiberglass insulation as well as in textile fiberglass (a fabric-like material commonly used in skis, circuit boards, and other similar applications).

The primary industrial use of boric acid is in the manufacture of monofilament fiberglass usually referred to as textile fiberglass. Textile fiberglass is used to reinforce plastics in applications that range from boats, to industrial piping to computer circuit boards.[18]

In the jewelry industry, boric acid is often used in combination with denatured alcohol to reduce surface oxidation and firescale from forming on metals during annealing and soldering operations.

Boric acid also used in the production of the glass in LCD flat panel displays.

In electroplating, boric acid is used as part of some proprietary formulas. One such known formula calls for about a 1 to 10 ratio of H3BO3 to NiSO4, a very small portion of sodium lauryl sulfate and a small portion of H2SO4.

It is also used in the manufacturing of ramming mass, a fine silica-containing powder used for producing induction furnace linings and ceramics.

Boric acid is one of the most commonly used substances that can neutralize active hydrofluoric acid (HF). It works by forcing the free F- anions into complex salts. This process defeats the extreme toxicity of hydrofluoric acid, particularly its ability to sequester ionic calcium from blood serum which can lead to cardiac arrest (amongst other things); such an event can occur from just minor skin contact with HF.