What are moisturizers?
Moisturizers or moisturizing creams are special cosmetic products indicated to prevent and or treat dry skin although not all products are as effective as claimed. Some moisturizers are formulated to intend to treat certain skin conditions.
What ingredients are commonly used in moisturizers?
Humectants such as urea, glycerin, alpha hydroxy acids, lactic acid and emollients such as butyl stearate, glycerin, lanolin, mineral oil and petrolatum are commonly used although some others such as vitamins, minerals or plant extracts may also be used. Humectants are used to absorb water from the air and keeps the moisture to the skin preventing loss of moisture. Emollients water-based or oil-based are used to smooth and lubricate rough skin. The oil-based leaves some residue on the skin while the water-based does not.
Other nonfunctional ingredients that may probably be used include fragrances and preservatives, which sometimes can cause skin reactions.
How does the FDA regulate moisturizers?
FDA regards skin moisturizers as cosmetics just like other products such as perfumes, lipsticks, fingernail polishes, eye and facial makeup preparations, shampoos, permanent waves, hair colors, toothpastes, and deodorants. But moisturizers can also be drugs when they are intended to treat medical conditions. Marketing of moisturizers intended to be used as cosmetic products does not have to get approved by the FDA unless the products are indicated for medical treatment. Because of this, there is no guarantee that moisturizers without FDA approval are safe or effective as claimed.
How to choose a moisturizer?
It depends upon the skin type, age, and skin conditions. For normal skin (why do people with normal skin use moisturizers?), people can use the water-based type. People with dry skin may use oil-based moisturizers that contain urea or propylene glycol. Oil skin is prone to acne and breakouts and they better be treated with an oil-free, water based moisturizer without comedogenic ingredients. For sensitive skin that is susceptible to skin irritations, use moisturizers that do not contain allergens or such fragrances or dyes.
Are moisturizers safe?
Unlike drugs, cosmetic moisturizers do not have to go through trials to demonstrate their efficacy and safety. So there is some uncertainty.
Do moisturizers increase risk of skin cancer?
The possibility that use of certain moisturizers may increase skin cancer risk was discovered by Allan Conney and colleagues at Rutgers University. They found hairless mice whose skin was damaged by UV radiation were at higher risk of skin cancer known as squamous cell carcinoma. The finding suggests that certain moisturizers could do more harm than good to the skin damaged by UV radiation.
However, The carcinogenicity may not be applicable to humans. But more research is needed to prove or disprove the possibility because humans are not mice. Furthermore, the mice used in the study are the type that is susceptible to skin cancer due to their genetics.
The study was reported as follows:
Cancer
researchers at Rutgers University reported a study
Thursday in the Aug. 14, 2008 issue
of the Journal of Investigative Dermatology suggesting that some
moisturizing creams or moisturizers may increase the odds of getting a type of
skin cancer known as squamous cell carcinoma.
This type of skin cancer is more common, but less risky than
melanoma.
Squamous cell carcinoma on the
skin grows slowly, but can spread fast.
For the study, Dr. Allan Conney and colleagues first exposed
hairless mice, a model animal that is prone to getting skin cancer, to UVB
radiation twice a week for 20 weeks, which resulted in mice with a high risk of
skin tumors over the next several months.
They found topical applications of 100 mg of four
moisturizers once a day five days a week for 17 weeks to the high risk mouse'
skin boosted the rate of tumor formation and the growth rate of tumors.
Treatment of high-risk mice with Dermabase, Dermovan,
Eucerin, or Vanicream for 17 weeks increased the total number of histologically
characterized tumors by 69%, 95%, 24%, and 58%, respectively.
Conney told Reuters that his discovery was incidental.
His team planned to test caffeine's
preventative effect against skin cancer using moisturizers as a carrier. But it
happened that they found the moisturizers are tumorigenic in the mice.
The researchers did not know the mechanism behind the
increased risk of skin cancer, but suspected that two ingredients mineral oil
and sodium laurel sulphate are the culprits. They tested a cream without these
ingredients and found it did not increase risk of skin cancer in the mice.
Rutgers and Johnson & Johnson have jointly patented a so
called custom blend moisturizer without these chemicals, Reuters reported.
Squamous cell carcinoma can be caused by exposure to a
series of carcinogens including x-ray, arsenic, chemical carcinogens, and
ultraviolet radiation among others.
