Quick Guide To Cosmetic Formulation Ingredient Categorization & Selection

There are thousands of different cosmetic products on the market, all with differing combinations of ingredients. In the United States alone there are approximately 15,000 unique chemical ingredients approved for use in the manufacture of personal care products. Therefore researching ingredients is one of the most important skills for a cosmetic formulator.

While the formula of each product differs slightly, most cosmetics contain a combination of at least some of the following core ingredients: water, emulsifier, preservative, thickener, emollient, colour, fragrance and pH stabilisers. Let us go through some of the core ingredients in detail..

Free radicals: Ions or molecules that have an unpaired electron which causes them to be highly chemically reactive towards other substances, including our skin cells. They attach and bind themselves to other molecules which changes the chemical structure and results in damage or destruction of the original molecule.

Sebum: A complex oily mixture of glycerides, fatty acids, wax, squalene and cholesterol that’s produced by the sebaceous glands. Except on our palms and soles, these glands are found all over our body with the highest concentration found on our back, forehead and chin. Sebum is vital to skin health. It provides a layer of protection from bacteria and fungi as well as reducing water loss from the inside but also providing a waterproof shield from the outside. We need just the right amount of sebum for optimal protection, however, too much can lead to clogged pores and eventually acne.

Antioxidant: A molecule that inhibits, or stops, the oxidation of other molecules. They occur naturally in plants, animals and plant based foods like vegetables, tea, wine and chocolate. Our own bodies also naturally produce a complex system of antioxidants to combat oxidation or the chemical reactions that create free radicals.

Humectant: A substance that attracts water molecules (usually from the deeper layers, like the dermis), to the epidermis or upper layer of the skin. By doing so, it prevents dryness and maintains the skin’s suppleness. One of the most well-known humectants is glycerin which naturally occurs in all lipids (i.e. fats), including our own skin. Note that a lot of humectants have emollient properties, while not all emollients have humectant properties. A combination of the two make for the best moisturizers.

Emollients: Waxy lubricating agents that contain a mixture of compounds used to soften, smooth and hydrate the skin. They also contain occlusive properties, meaning they provide a layer of protection which helps prevent water loss. There are a variety of emollient ingredients including plant oils, mineral oils, shea butter, cocoa butter, triglycerides, stearates and fatty acids like lanolin.

Polyphenols: Naturally occurring phytochemicals or micronutrients that are found abundantly in fruit, vegetables, red wine, tea, plant oils to name but a few. They influence and contribute to the bitterness, astringency, color, flavor, odor and oxidative stability of the food or liquid. Phytochemicals are important because they have potent antioxidant properties which helps protect cells from free radicals. They also have a range of other positive biological effects like inhibiting angiogenesis, reducing inflammation and promoting normal blood pressure and blood sugar levels.

4 Major Types Of Polyphenols:
- Phelonic acid (blueberries, coffee, kiwifruits, plums, cherries and apples)
- Stilbenes (red wine and peanuts)
- Flavonoids (fruits, vegetables, legumes, red wine and green tea)
- Lignans (flax, legumes, cereals, grains, fruits and algae)

Emulsifier: Emulsifiers refers to any ingredient that helps to keep unlike substances (such as oil and water) from separating. Many cosmetic products are based on emulsions, small droplets of oil dispersed in water or small droplets of water dispersed in oil.

Preservatives: They are very important ingredients. They are added to cosmetics to extend their shelf life and prevent the growth of microorganisms such as bacteria and fungi, which can spoil the product and possibly harm the user. Preservatives used in cosmetics can be natural or synthetic (man-made), and perform differently depending on the formulation of the product.

Thickeners: Thickening agents work to give products an appealing consistency. There are four different chemical families of thickeners:

1. Lipid thickeners are usually solid at room temperature but can be liquefied and added to cosmetic emulsions.
2. Natural thickeners come, as the name suggests, from nature. They are polymers that absorb water, causing them to swell up and increase the viscosity of a product.
3. Mineral thickeners are also natural, and as with the naturally derived thickeners mentioned above, they absorb water and oils to increase viscosity, but give a different result to the final emulsion than the gums.
4. Synthetic thickeners are often used in lotion and cream products. The most common synthetic thickener is carbomer, an acrylic acid polymer that is water-swellable and can be used to form clear gels.

Chelating Agents: Molecules with a specific 3D structure that are able to complex with metal ions. Chelating agents can help stabilize cosmetics and prevent their deterioration by catching (sequestering) metal ions.

Surfactants: Most widely used ingredients in cosmetics and cosmeticeutical products. They have a unique chemical structure, including both a hydrophilic and a hydrophobic portion, which enables them to be dissolved both in water and in oil. Surfactants lower the surface tension between two liquids or between a liquid and a solid, making them suitable for many applications. Their contribution to the formulation is, stability, and applicability of personal care and cosmetic products.

Pigments/Colouring agents: Colouring agents are central components of some cosmetic products.

Colorants are soluble (in water or in oil) synthetic organic colouring agents. They are used to colour cosmetic products such as skin care or toiletries, among others.
Pigments are insoluble colouring agents, which when used, remain in the form of crystals or particles. They are further divided into mineral and organic pigments and selected as per the intended applications.

Before we conclude, we need to understand that when it comes to ingredients selection for the cosmetic formulations, it totally depends on the cosmetic formulator's skills and his/her product ideas. Once you start to research cosmetic ingredients, you need to feel, smell and see the ingredient to get to know it properly.