The molecule that looks oh so like water but definitely isn’t, has numerous applications in the cosmetics and personal care industry. Before we get to those, let’s take deeper look at the product and its solutions.
What is hydrogen peroxide?
Hydrogen peroxide only differs from the ubiquitous H2O by the addition of one oxygen atom, but that small modification of chemical formula and of structure creates an enormous difference in the properties and functions of the two chemicals.
Hydrogen peroxide, H2O2, is usually made available to consumers in the form of an aqueous solution i.e., it is dissolved in water. The concentration of that solution matters – it matters a lot! Most home use involves hydrogen peroxide solutions that are 3% H2O2 by mass, i.e. 30 g of H2O2 in every 1000 g of solution. Other concentrations are available for more specialized use such as 6%, 10% and 30+%, the latter two being relatively uncommon for general use.
In the drug store
It’s likely that you’ve seen hydrogen peroxide in pharmacies, and that you’ve seen the distinct packaging associated with it. Hydrogen peroxide is usually sold in opaque, brown, plastic bottles, and there’s a reason for that.
In sunlight hydrogen peroxide will spontaneously decompose into water and oxygen gas according to the chemical equation below.
2H2O2(aq) = 2H2O(l) + O2(g)
Keeping hydrogen peroxide in opaque, plastic bottles achieves two things. Firstly, it stops light from reaching the solution and so prevents the decomposition into water and oxygen. This means that the hydrogen peroxide stays fresh, and that you aren’t just buying a bottle of water.
Secondly, if some decomposition does take place and oxygen gas – and therefore pressure – builds up in the bottle, then the risk of injury from a potentially exploding bottle is reduced if the vessel is made of soft plastic and not glass.
What does the label mean?
Hydrogen peroxide solutions are sometimes marketed and sold using the term “volume.” This can be confusing, but relates to the volume of oxygen gas that can be produced by the various concentrations of solution. One liter (1L) of 3% H2O2 solution will release 10 L of oxygen gas, hence the term ‘10 volume’ or V10; a 6% solution may be described as ‘20 volume’ etc.
The production of oxygen gas via the decomposition of the solution is at the heart of most applications of hydrogen peroxide, as the oxygen will act as an oxidizing agent when it interacts with organic matter.
What are oxidizing agents?
In the simplest terms an oxidizing agent is a substance that causes oxidation. Well, what do we mean by oxidation? There are several definitions of oxidation in chemistry that involve gaining oxygen, and losing either hydrogen or electrons, but for the purposes of discussing hydrogen peroxide we can simply consider it to be a reaction that causes the breakdown and destruction of various substances that the solution comes into contact with. When those substances are unpleasant bacteria or viruses, hydrogen peroxide provides a useful service in destroying them.
In medicine and first-aid
Hydrogen peroxide is commonly used in medical setting as a disinfectant for hard surfaces, and for cleaning reusable instruments. Relatively high concentrations can be used for these purposes.
When it comes to use as a minor wound cleaner, or as a gargle for curing a sore throat at home, the dilutions of the solution must be considered carefully as hydrogen peroxide can be corrosive to tissue at higher concentrations. Typically, when used in more sensitive situations such as on skin or in the mouth, hydrogen peroxide is likely to be labeled as an antiseptic rather than a disinfectant, although its role in each case is similar. 3% hydrogen peroxide solutions are the usual choice where an antiseptic is needed.
Safety and hydrogen peroxide
Hydrogen peroxide is an entirely safe product when used in the correct manner and with appropriate caution. Indeed, it comes in ‘Food Grade’ quality, but that does not mean that it should be consumed, rather it means it can be used in the context of food preparation and manufacture. In the late 1980s a number of bogus claims were made about the ability of industrial strength (30-35%) hydrogen peroxide to cure all kinds of diseases from cancer to AIDS. This misleading information led to at least one death, and several hospitalizations. At the 3% level, hydrogen peroxide can be used quite safely in the home, but as the concentration of the solutions increases its growing ability to attack organic matter (tissue) needs to be taken into account.
Cosmetics and personal care products
In the cosmetics and personal care industry hydrogen peroxide can serve several purposes. Chief among those are its roles as bleaching agent, its use as an antiseptic, and its role as a preservative. The way that the hydrogen peroxide works in each case is similar, with its oxidative powers at the core of its use.
Hydrogen peroxide solutions may be used to ‘bleach’ hair, i.e., to remove the pigment in hair to turn it ‘blonde’. The hair isn’t ‘bleached’ per se, but the hydrogen peroxide oxidizes the pigments to lighten them. 12% and above hydrogen peroxide is often used for this purpose and as such products used for lightening hair should be handled with great care.
At lower concentrations hydrogen peroxide can be used in a similar manner to lighten dark spots on skin. It is sometimes used to whiten teeth and has been proven to be effective in removing blood stains from fabric especially if those stains are relatively fresh.
Some cosmetic products such as skin toners and acne treatments will contain low concentrations of hydrogen peroxide. The concentrations must be relatively low, since H2O2 has the ability to attack tissue and to cause inflammation of the skin, so any use should be carefully regulated and conducted with caution. Hydrogen peroxide’s effectiveness in actually curing acne is unproven, but its presence is designed to prevent the growth of bacteria on the skin. This may help, but as noted above, the potential for aggravating the skin certainly exists, and it may be unwise to use the pure solution at any concentration directly as an acne treatment.
As a strong oxidizing agent, hydrogen peroxide will act as an antimicrobial agent destroying bacteria, viruses, and microorganisms in the process. This helps to prolong the shelf-life of personal care products. Hydrogen peroxide solution can also deactivate enzymes, resulting in the stabilization of personal care products, preventing their breakdown.< Back