Preservatives are a necessary ingredient because it prevents the growth of microorganisms such as bacteria and fungi. Therefore, preservatives are used for the safety of the user as well as to increase the shelf life of the product. Some examples of preservatives are parabens, benzyl alcohol, salicylic acid, formalidehyde and tetra sodium EDTA (ethylenediaminetetra-acetic acid).
Preservatives work by disrupting the cell walls of microbes (lysing the membrane kills the microbe since the intracellular fluid seeps out). However, the way they do this differs between the preservative used. For example, natural preservatives like honey and sugar bind to water molecules. This makes the water inaccessible to microbes, which need it to grow and multiply.
Another way preservatives prevent the growth of microbes is by controlling the pH. Microbes’ ideal pH is between 5-7.5. Therefore, adding salicylic acid to a mixture keeps the pH below acidic making microbes unable to exist.
Parabens, the most common preservative, work at a broad spectrum of pHs and against several microorganisms. The function of these molecules are not well understood but scientists believe that these molecules easily permeate the cell membrane of microbes and are able to disrupt the lipid bilayer and ultimately kills the cells by leaking its contents.
A cosmetic product that is labeled preservative-free or paraben-free may be seen as more attractive since it is debated whether or not these preservative material have a negative health effect. However, you must keep in mind that these products may develop microbes quicker and thus keep an eye out for signs that bacteria is forming. If you see black/green dots in the formula (bacteria and fungi colonies) or if the product smells different than its initial scent, dispose of the product since it is most likely microbe-infected.
Emulsifiers are materials that keep two substances that would naturally separate bound together. A common emulsion in creams, moisturizers, and lotions is water and oil. Naturally, water and oil separate due to differences in polarity. Water is a super polar substance. The oxygen in H2O has a high electronegativity meaning that the atom attracts bonding pairs of electrons. Therefore, the oxygen pulls on the electrons of the two hydrogen atoms creating a negative charged end (from the oxygen) and a positive charged end (from the hydrogen atoms). On the other end, oil is typically made up of long strands of hydrocarbons. Carbon atoms are much weaker in electronegativity when compared to oxygen, which ultimately makes the oil a non-polar substance. With the principle of “like dissolves like”, the water and oil do not interact but rather separate completely.
So, here are where emulsifiers come in. Emulsifiers have hydrophilic heads (water-loving) and lypophilic tails (oil-loving). The heads bond with water molecules while the tails bond with oil molecules, thus joining the two molecules together.
Common emulsifiers include Borax with Beeswax, Beeswax, BTMS 25%, Carbomer, Cetaryl Alcohol, Emulsifying Wax-NF, Lecithin, PEG-20 Stearate, Propylene Glycol, Silky Emulsifying Wax, Stearyl Alcohol NF, and Polysorbate 80. Below is Polysorbate 80 which shows the two distinct parts of the molecule. The hydrophilic head is characterized by the large number of oxygen atoms (to bond with H2O) while the lypohilic tail is comprised of nonpolar hydrocarbons (to bond with oil).
Water is used in almost all cosmetic products as a solvent: dissolves other ingredients and makes emulsions (a Main 8 that will be explained in another post). Therefore it is found in lotions, shampoo and conditioners, skin care products, creams, makeup, etc. It is usually listed as the first ingredient on the label due to its high concentration but it is not usually listed as water. Instead, it is called aqua or distilled/purified water because the water that scientists use is completely microbe, toxin and pollutant free.
However, studies have found that only 10% concentration of water on the outermost layer of skin is all that is needed to keep the skin soft. In fact, externally, water dries out the skin by evaporating with the natural oils that skin produces thus drying out the skin. Therefore, the water that is in these cosmetic products is not the moisturizing agent but rather acts solely as a solvent and a component to the formation of emulsions.
Reading the label of cosmetic products is daunting … but it shouldn’t be.
This is where I come in to help explain the different mechanisms and composition of the ingredients. Yes, most of the words look like they come out of books written in another language but do not let this discourage you from exercising your right to know what is being smeared, massaged, and brushed onto your skin. Given that the average woman uses 9-15 different products daily and that each product roughly contains 15-50 ingredients (that’s over 500 chemicals being absorbed by your skin), knowing the different types of products and their compositions is incredibly important in making smart decisions on what you are purchasing.
Obviously, picking up a product, reading the label, and knowing exactly the structure, function and purpose of each chemical listed is ideal. However, this is certainly infeasible given numerous factors. Therefore, this blog will be focused on giving a general look into common cosmetic products and a deep understanding of the core ingredients that make up most products.
You should feel power over the label, not the other way around so join me on my exploration of cosmetic products under the microscope.