Propylene Glycol (PG): Propylene Glycol serves as a humectant - a substance that helps to retain moisture content. It is also a wetting agent and solvent, so it is used by many cosmetic manufacturers to facilitate the process of dissolving and combining ingredients. Propylene Glycol is widely used in skin cream, and many other personal care products. Propylene Glycol is also one of the key ingredients in embalming fluid, anti-freeze, brake fluid, hydraulic fluid, de-icer, paints and floor wax. The Material Safety Data Sheet (MSDS) for Propylene Glycol clearly states: "Implicated in contact dermatitis, kidney damage and liver abnormalities; Can inhibit skin cell growth in human tests, and can damage cell membranes causing rashes, dry skin and surface damage." The MSDS also cautions: Acute Effects: "May be harmful by inhalation, ingestion or skin absorption. May cause eye irritation, skin irritation. Exposure can cause Gastrointestinal disturbances, Nausea, Headache, Vomiting and Central Nervous System depression." Propylene Glycol is toxic, and it will actually retards your skin's ability to maintain normal cellular regeneration.
In 1992, the FDA proposed a ban on Propylene Glycol in louse-killing products because it has not been shown to be safe and effective for its stated claims, yet, Propylene Glycol is allowed to be used in cosmetics in concentrations up to 50%. Animals who were experimentally exposed (not by us) to Propylene Glycol suffered all of the above symptoms, including mild to profound central nervous system depression as well as heart arrhythmia, respiratory failure, narcosis (profound stupor), growth depression, decreased blood pressure, and even death. The recommended method of storage for undiluted propylene glycol is in an explosion-proof refrigerator.
Butylene Glycol: Used in cosmetics to resist humidity, to retain scents and as a preservative. Has a similar toxicity as ethylene glycol, which when ingested may cause depression, vomiting, drowsiness, coma, respiratory failure, convulsions, renal damage, kidney failure and death.
Urea: A component of urine, though synthetic versions are used in cosmetics. In small amounts urea has good water-binding and exfoliating properties for skin; in larger concentrations it can cause inflammation.
Parabens: (Butylparaben, Methylparaben, Propylparaben) These are perhaps the most commonly used preservatives in the United States. They are considered relatively safe and non-toxic, however, methylparaben can cause allergic reactions, and propylparaben can cause contact dermatitis.
Triethanolamine: A chemical used in cosmetics to adjust the pH, and also used as an emulsifier. May cause allergic reactions, including eye problems, dryness of skin, and could be toxic if absorbed into the body over a long period of time. In Italy, at the University of Bologna, it was discovered that this chemical ingredient was the most frequent sensitizer among the common emulsifiers used in cosmetics. Also used as a chemical coating to preserve fresh fruit. Concentration should not exceed 5% when used in products that come in contact with the skin.
Bearberry Extract and Licorice Extract: Contains arbutin. Arbutin can inhibit melanin production, though this has only been shown in vitro and in pure form, not in a cosmetic formulation. The fractional amounts of bearberry extract used in cosmetics and the small amount of arbutin the extract contains mean this is unlikely to affect skin or melanin. Arbutin - Hydroquinone derivative isolated from the leaves of the bearberry shrub, cranberry, blueberry, and most types of pears. Because of arbutin's hydroquinone content, it can have melanin-inhibiting properties. Although the research describing arbutin's effectiveness is persuasive (even if almost all of the research has been done on animals or in vitro), concentration protocols have not been established. That means we just don't know how much arbutin it takes to have an effect in lightening the skin. Moreover, most cosmetics companies don't use arbutin in their products because there are Shiseido-owned patents controlling its use in skin-care products for skin lightening. To get around this problem, many cosmetics companies use plant extracts that contain arbutin, such as bearberry. There is limited research, mostly animal studies or in vitro, showing that the plant extracts that contain arbutin have any impact on skin. Whether or not these extracts are effective in the small amounts present in cosmetics has not been established.
Peppermint Oil: Both the oil and the extract can have anti-microbial properties but they can also have an irritating, sensitizing effect on skin. Ingredients such as menthol, peppermint, camphor, and mint are considered counter-irritants. Counter-irritants are used to induce local inflammation for the purpose of relieving inflammation in deeper or adjacent tissues. In other words, they substitute one kind of inflammation for another, which is never good for skin. Irritation or inflammation, no matter what causes it or how it happens, impairs the skin's immune and healing response. And although your skin may not show it, or doesn't react in an irritated fashion, if you apply irritants to your skin the damage is still taking place and is ongoing, so it adds up over time.
Hydrolized Wheat Starch: Mostly used in food. May be contaminated with impurities linked to cancer or other significant health problems. Insufficient toxicity data to know if its use in cosmetics is safe.
DMDM Hydantoin: A formaldehyde-releasing preservative. A common type of preservative found in cosmetics; however, there is no higher level of skin reaction to formaldehyde-releasing preservatives than to other preservatives. There is concern that when formaldehyde-releasing preservatives are present in a formulation with amines, such as triethanolamine (TEA), diethanolamine (DEA), or monoethanolamine (MEA), that nitrosamines can then be formed, because nitrosamines are carcinogenic substances that can potentially penetrate skin. Whether or not that poses a health risk of any kind has not been established.
Ethylenediamine Tetraacetic Acid (EDTA): Widely used by cosmetic manufacturers as a sequestering preservative. It may be irritating to the skin and mucous membranes and can cause allergies such as asthma and skin rashes.
Imperata Cylindrica Root Extract: There is no research to support the claims that this extract has any benefit for skin.
Siegesbeckia Orientals Extract: Chinese herb (also known as St. Paul’s wort); there is no research showing that it has any benefit for skin.