Moisturizer
Encyclopedia
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
(epidermis) softer and more pliable, by increasing its hydration (water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
content) by reducing evaporation. Naturally occurring skin lipids and sterol
Sterol
Sterols, also known as steroid alcohols, are a subgroup of the steroids and an important class of organic molecules. They occur naturally in plants, animals, and fungi, with the most familiar type of animal sterol being cholesterol...
s as well as artificial or natural oils, humectant
Humectant
A humectant is a hygroscopic substance. It is often a molecule with several hydrophilic groups, most often hydroxyl groups, but amines and carboxyl groups, sometimes esterified, can be encountered as well; the affinity to form hydrogen bonds with molecules of water is crucial here.Since...
s, emollients, lubricant
Lubricant
A lubricant is a substance introduced to reduce friction between moving surfaces. It may also have the function of transporting foreign particles and of distributing heat...
s, etc. may be part of the composition of commercial skin moisturizers. They usually are available as commercial products for cosmetic
Cosmetics
Cosmetics are substances used to enhance the appearance or odor of the human body. Cosmetics include skin-care creams, lotions, powders, perfumes, lipsticks, fingernail and toe nail polish, eye and facial makeup, towelettes, permanent waves, colored contact lenses, hair colors, hair sprays and...
and therapeutic uses, but can also be made at home using common pharmacy
Pharmacy
Pharmacy is the health profession that links the health sciences with the chemical sciences and it is charged with ensuring the safe and effective use of pharmaceutical drugs...
ingredients.
By indication
Moisturizers prevent and treat dry skin, protect sensitive skin, improve skin tone and texture, and mask imperfections.Preservation of normal skin
Moisturizers can be used to prevent the skin from becoming too dry or oily, such as with light, nongreasy water-based moisturizers. Such moisturizers often contain lightweight oils, such as cetyl alcoholCetyl alcohol
Cetyl alcohol, also known as 1-hexadecanol and palmityl alcohol, is a fatty alcohol with the chemical formula CH315OH. At room temperature, cetyl alcohol takes the form of a waxy white solid or flakes....
, or silicone-derived ingredients, such as cyclomethicone.
Dry skin
For treating skin dryness, the most appropriate moisturizers are heavier, oil-based moisturizers that contain ingredients such as antioxidantAntioxidant
An antioxidant is a molecule capable of inhibiting the oxidation of other molecules. Oxidation is a chemical reaction that transfers electrons or hydrogen from a substance to an oxidizing agent. Oxidation reactions can produce free radicals. In turn, these radicals can start chain reactions. When...
s, grape seed oil
Grape seed oil
Not to be confused with Rapeseed oil.Grape seed oil is a vegetable oil pressed from the seeds of various varieties of Vitis vinifera grapes, an abundant by-product of winemaking.- Cooking :...
or dimethicone. For very dry, cracked skin, petrolatum-based products are preferable, as they are more lasting than creams and are more effective in preventing water evaporation.
Oily skin
In oily skin, moisturizers can still be useful after activities causing skin dryness, such as other skin care products and washing. For oily skin, water-based moisturizers that are specifically noncomedogenic are preferable, as there is less risk of comedoComedo
Comedo may refer to:*Blackhead *Whitehead : non inflamed pore blocked with sebum, a symptom of acne vulgaris...
formation.
Aging skin
Appropriate moisturizers to keep aging skin soft and well hydrated are oil-based ones that contain petrolatum as the base, along with antioxidantAntioxidant
An antioxidant is a molecule capable of inhibiting the oxidation of other molecules. Oxidation is a chemical reaction that transfers electrons or hydrogen from a substance to an oxidizing agent. Oxidation reactions can produce free radicals. In turn, these radicals can start chain reactions. When...
s or alpha hydroxy acids against wrinkle
Wrinkle
A wrinkle is a fold, ridge or crease in the skin. Skin wrinkles typically appear as a result of aging processes such as glycation or, temporarily, as the result of prolonged immersion in water. Wrinkling in the skin is caused by habitual facial expressions, aging, sun damage, smoking, poor...
s.
Sensitive skin
On sensitive skinSensitive skin type
Sensitive skin is a skin condition in which skin which is prone to itching and irritation experienced as a subjective sensation when using cosmetics and toiletries. When questioned, over 50% of women in the UK and US report that they have sensitive skin....
(which otherwise is susceptible to skin irritations, redness, itching or rashes), it is preferable with moisturizers that contain soothing ingredients such as chamomile
Chamomile
Chamomile or camomile is a common name for several daisy-like plants of the family Asteraceae. These plants are best known for their ability to be made into an infusion which is commonly used to help with sleep and is often served with either honey or lemon. Because chamomile can cause uterine...
or aloe
Aloe
Aloe , also Aloë, is a genus containing about 500 species of flowering succulent plants. The most common and well known of these is Aloe vera, or "true aloe"....
and that minimize potential allergen
Allergen
An allergen is any substance that can cause an allergy. In technical terms, an allergen is a non-parasitic antigen capable of stimulating a type-I hypersensitivity reaction in atopic individuals....
s such as fragrances or dye
Dye
A dye is a colored substance that has an affinity to the substrate to which it is being applied. The dye is generally applied in an aqueous solution, and requires a mordant to improve the fastness of the dye on the fiber....
s, as well as irritant
Irritation
Irritation or exacerbation, in biology and physiology, is a state of inflammation or painful reaction to allergy or cell-lining damage. A stimulus or agent which induces the state of irritation is an irritant...
s such as acids.
Eczema
In eczemaEczema
Eczema is a form of dermatitis, or inflammation of the epidermis . In England, an estimated 5.7 million or about one in every nine people have been diagnosed with the disease by a clinician at some point in their lives.The term eczema is broadly applied to a range of persistent skin conditions...
it is generally best to match thicker ointments to the driest, flakiest skin. Light emollients like aqueous cream
Aqueous cream
Aqueous Cream BP is a light, paraffin-based emulsion which is officially registered in the British Pharmacopoeia and categorised by the British National Formulary as a non-proprietary emollient preparation...
may not have any effect on severely dry skin. Some common emollients for the relief of eczema include Oilatum, Balneum, Medi Oil, Diprobase, bath oils and aqueous cream. Sebexol, Epaderm ointment, Exederm and Eucerin lotion or cream may also be helpful with itching. Lotions or creams may be applied directly to the skin after bathing to lock in moisture. Moisturizing gloves (gloves which keep emollients in contact with skin on the hands) can be worn while sleeping. Generally, twice-daily applications of emollients work best. While creams are easy to apply, they are quickly absorbed into the skin, and therefore need frequent reapplication. Ointments, with less water content, stay on the skin for longer and need fewer applications, but they can be greasy and inconvenient.
Recently, ceramide
Ceramide
Ceramides are a family of lipid molecules. A ceramide is composed of sphingosine and a fatty acid. Ceramides are found in high concentrations within the cell membrane of cells. They are one of the component lipids that make up sphingomyelin, one of the major lipids in the lipid bilayer...
s, which are the major lipid constituent of the stratum corneum
Stratum corneum
The stratum corneum is the outermost layer of the epidermis, consisting of dead cells that lack nuclei and organelles. The purpose of the stratum corneum is to form a barrier to protect underlying tissue from infection, dehydration, chemicals and mechanical stress...
, have been used in the treatment of eczema. They are often one of the ingredients of modern moisturizers. These lipids were also successfully produced synthetically in the laboratory
Laboratory
A laboratory is a facility that provides controlled conditions in which scientific research, experiments, and measurement may be performed. The title of laboratory is also used for certain other facilities where the processes or equipment used are similar to those in scientific laboratories...
.
Mechanisms of action
There are three methods used to moisturize skin:- Occlusives: These work by forming a thin film on the surface of the skin to prevent any loss of moisture.
- Humectants: These attract water from the air in order to moisturize the skin.
- Restoration of Deficient Materials: These are more complex and try to restore natural moisturizing factors on the skin such as amino-lipids.
Risks of moisturizers
Two factors have to be considered when assessing the safety of a moisturizer:- The safety of the ingredients it contains. There are on-line databases like Skin Deep where consumers can get information about individual cosmetic ingredients.
- The risk of bacterial contamination.
A recent study discovered that the application of certain moisturizers increases the incidence of skin cancer in high-risk mice. Note: these animals were subjected to UVB radiation in high doses over a long period of time prior to application of moisturizers. Four popular moisturizers were tested, providing the same result. It is not yet known if the same applies to humans. A fifth moisturizer, specially prepared without mineral oil
Mineral oil
A mineral oil is any of various colorless, odorless, light mixtures of alkanes in the C15 to C40 range from a non-vegetable source, particularly a distillate of petroleum....
and sodium lauryl sulphate, had no such effect. The researchers asked Johnson & Johnson
Johnson & Johnson
Johnson & Johnson is an American multinational pharmaceutical, medical devices and consumer packaged goods manufacturer founded in 1886. Its common stock is a component of the Dow Jones Industrial Average and the company is listed among the Fortune 500....
to produce this cream for the study, which the pharmaceutical company later patented.
Some people are sensitive or allergic to certain chemical components, which can cause irritation, rashes, and other allergic reactions.
As with most skin-care products, there is a risk of moisturizers being contaminated with bacteria that can cause disease.