Neutrogena Healthy Skin Liquid Makeup is advertised as an "exclusive blend of antioxidants and SPF 20." Like many cosmetics, most of its ingredients read like a foreign language. The first ingredient is easy: water. But unless you're a chemist, most of the remaining 40 ingredients are incomprehensible. Even though some ingredients serve more than one function, placing them into general categories according to their purpose is a great way to understand the ingredients.

Product Quality

Ingredients that ensure product quality fall into many different categories: binding, thickening, stabilizing, anticaking, absorbing, emulsifying, emulsion stabilizing and viscosity controlling (thickness). These chemicals ensure that different ingredients in the makeup stick together, create thickness and increase shelf life. Chemicals classified as opacifying ingredients reduce the transparency or translucency of the makeup.

The list of ingredients in this category is long: Talc (absorbent, anticaking, pacifying, bulking, skin protecting), polyglyceryl-4 diisostearate/polyhydroxystearate/sebacate (emulsifying, emulsion stabilizing, surfactant), magnesium sulfate (thickening, viscosity controlling), HDI/trimethylol hexyllactone crosspolymer (anticaking), boron nitride (absorbent, opacifying), alumina (anticaking, bulking, opacifying, viscosity controlling), polyhydroxystearic acid (emulsifying), silica (anticaking, absorbent, opacifying, viscosity controlling), quaternium-90 bentonite (viscosity controlling), propylene carbonate (viscosity controlling), silica silylate (anticaking, bulking, emulsion stabilizing, viscosity controlling, emollient, skin conditioning), dimethicone/vinyl dimethicone crosspolymer (viscosity controlling), aluminum starch octenylsuccinate (absorbent, anticaking, viscosity controlling), magnesium carbonate (absorbent, binding, opacifying, bulking), disodium EDTA (viscosity controlling, stabilizing) and iron oxide (opacifying).

Preservatives

Preservatives are used to prevent contamination from bacteria, which is crucial even though preservatives may irritate the skin. Neutrogena Healthy Skin Liquid Makeup uses three preservatives: sorbic acid, phenosyethanol and methylisothiazolinone. Sorbic acid can be obtained from mountain ash berries or developed synthetically. It has a low risk of causing skin irritation. Phenosyethanol is also less irritating to skin because it doesn't release formaldehyde, says cosmeticscop.com. Methylisothiazolinone is a powerful preservative known to carry a high risk of irritating the skin.

Skin Conditioning

Chemicals that maintain the skin's condition are classified as emollients and humectants. Emollients soften and smooth the skin by preventing water loss; humectants attract and hold moisture. The emollient ingredients include cyclopentasiloxane, ethylhexyl palmitate, cyclohexasiloxane, C12-15 alkyl benzoate (also antimicrobial), cetyl dimethicone, stearoxymethicone/dimethicone copolymer (also viscosity controlling), dimethicone, and cyclomethicone and caprylyl glycol, which are both also humectants. The humectants are butylene glycol and glycerin.

Treatment

Titanium dioxide, which is listed as the active ingredient, blocks harmful sunlight. Benzotriazolyl dodecyl p-cresol protects the makeup from the effects of UV light. The antioxidant ingredients are pentaerythrityl tetra-di-t-butylhydroxyhydrocinnamate and tocopherol (vitamin E). Soymilk powder also provides antioxidant benefits and helps condition the skin. Chrysanthemum parthenium extract, also known as Feverfew, is a skin conditioner included as a treatment due to its anti-inflammatory properties that may reduce skin redness.

Application

Makeup must spread smoothly and evenly over the skin. Those qualities are categorized as film-forming and surfactant. The film-forming ingredient acrylate copolymer also helps makeup adhere to skin. Cetyl PEG/PPG-10/1 dimethicone is a surfactant that's also an emulsifying and skin conditioner. PPG-12/SMDI copolymer is an emollient that's also a surfactant and categorized as film-forming.