The most common hair spray ingredients are polyvinylpyrrolidone, polydimethylsiloxane, gum arabic, alcohols, hydrocarbons, and gum tragacanth. Hair spray was invented in the 1940s as a way to keep hair from moving around during the day. The same types of polymers in hair spray are found in wood glues, but they are water soluble for easy rinsing. Hair sprays are typically packaged in cans or bottles with a pressurized aerosol component.
Hair sprays are mostly made from synthetic ingredients such as vinyl acetate and acrylates. Two popular polymers, polyvinylpyrrolidone and polydimethylsiloxane, are responsible for hair spray's stickiness and long-lasting hold. Sprays that advertise as "all-day hold" tend to have more polydimethylsiloxane. Sometimes hair sprays contain pytocalcious chemicals, which deposit minerals at the hairs' roots to stiffen them up.
Other common hair spray ingredients include gums in alcohol solutions. Gum arabic, which comes from the hardened sap of African acacia trees, helps keep hair stiff for hours at a time. This ingredient is also used in paints, glues, inks, textiles, and cosmetics. It is usually harvested in the Middle East and sold to companies for a variety of purposes. For example, some Middle Eastern people use gum arabic to make sweet desserts.
Hair spray ingredients used to include chlorofluorocarbons, which propel the ingredients into a fine mist. CFCs, however, cause the ozone layer to deplete, so they are now banned in commercial sprays. Modern hair sprays use hydrocarbons and alcohol to create the mist effect.
Aminomethyl propanol is another ingredient used to control the pH of the hair spray solution. It keeps everything mixed together without separating too much, but usually one still needs to shake the can of hair spray to make sure everything is mixed together evenly. Another role of this ingredient is to make the hair spray resistant to humidity.
Sodium benzoate is a common preservative found in most commercial hair sprays. It also keeps the ingredients from rusting inside the can or getting infected with bacteria or viruses. Some hair sprays are advertised as moisturizing, and these usually contain Vitamin E or panthenol, which makes the hair shafts silky. Sodium PCA and butylene glycol are other common moisturizing ingredients. Additionally, Butylene glycol is the ingredient added to help hair spray retain its fragrances, which are frequently added to mask the smell of the synthetic ingredients.
Natural hair sprays typically include fewer ingredients and fewer chemicals. To totally control the ingredients in one's hair spray, there are recipes for making it at home. These generally involve simmering oranges and lemons in water to create a sticky liquid that can be sprayed on the hair.