The sale of moisturizers is huge. To understand them better it is important to know more about it. Enclosed the collected information. Moisturizers are not only used on the face but can be used all over the body. Most of the test are done to the facial skin. With the application, when it is for personal use, of a product it is best to test on different parts of the body and if possible on the most sensitive.
|The Natural Moisturizing Factor (NMF), a natural mixture of amino acids, lactates, urea and electrolytes, which help the stratum corneum retain water is known. Many moisturizers contain some combination of humectants, emollients, and other ingredients. Most moisturizers are water-based as they are easier to apply and tend to not leave a visible residue after application.
The moisturizing treatment involves a 4-step process:
•Repairing the skin barrier
•Increasing water content
•Restoring the lipid barriers’ ability to attract, hold and redistribute water
Ingredients of moisturizers are approximate:
Many skin care products contain salicylic acid. Studies have shown that salicylic acid is less irritating than skin care products containing alpha-hydroxy acids but has similar results in improving skin texture and color. But there is also a warning on allergic reactions to the product.
Skin care products containing hydroquinone are often called bleaching creams or lightening agents. These skin care products are used to lighten hyperpigmentation, such as age spots and dark spots related to pregnancy or hormone therapy (also called melasma). If a person is allergic to hydroquinones, it is possible to use products containing kojic acid or niacinamide (vitamin B3) instead. Pregnant women cannot use hydroquinone.
Kojic acid is a more recent remedy for treating pigment problems and age spots, it has a similar effect to hydroquinone. Kojic acid is made from a fungus.
Retinol is made from vitamin A, and it’s in many non-prescription skin care products. Retinol’s stronger counterpart is tretinoin, which is the active ingredient in Retin-A and Renova, available by prescription only. Retinol may improve mottled pigmentation, fine lines and wrinkles, skin texture, and skin tone and color. Pregnant women or nursing mothers cannot use retinol.
Vitamin C helps to minimize fine lines, scars, and wrinkles. It’s the only antioxidant that is proven to boost production of collagen, which is a key part of the skin’s structure. Vitamin C in its most commonly found forms is highly unstable when exposed to oxygen, making it useless. Choose one in a tube or a pump. Many vitamin C preparations do not penetrate the skin enough to make a difference.
Skin care products containing hyaluronic acid are often used with vitamin C products to assist in effective penetration. This molecule can hold 1,000 times its own weight in water, making it the ultimate hydrator. It also helps draw active ingredients deeper into the skin and may be called a cyclic acid. Hyaluronic acid occurs naturally in young skin, other tissues, and joint fluid. Hyaluronic acid is known to cushion and lubricate. Aging decreases the amount of hyaluronic acid gradually. Diet and smoking can also affect the body’s level over time. It is most frequently used to treat wrinkled skin although it doesn’t replace anything the body has naturally lost.
Sodium hyaluronate: Closely related to hyaluronic acid, this water-binding ingredient works to moisturize the skin. Like hyaluronic acid, it can hold more than 1,000 times its own weight in water.
Copper peptide seems to promote the production of collagen and elastin in the skin. It also acts as an antioxidant and promotes the production of glycosaminoglycans. Copper peptides have been shown to remove damaged collagen and elastin from the skin and scar tissue. The actual effects are different per person.
Alpha-lipoic acid diminishes fine lines, gives skin a healthy glow, and boosts levels of other antioxidants, such as vitamin C. Alpha-lipoic acid can enter all parts of a skin cell and can provide more protection than other antioxidants against so-called free radicals that can damage skin.
The brain makes DMAE. DMAE in skin care products shows minimal effects at best when applied on the skin for the reduction of fine lines and wrinkles
Glycerin: In addition to providing hydration, glycerin forms a barrier on the skin’s surface. This property allows it to glide on smoothly, but it can clog pores in high concentrations.
Shea butter: Widely used as a moisturizing ingredient, shea butter is believed to have anti-inflammatory properties.
Vitamin E: In addition to its antioxidant properties, nourishing vitamin E is a good moisturizer because it’s oil-soluble.
Traditionally, moisturization was believed to inhibit transepidermal water loss (TEWL) by occlusion. The water originates in the deeper epidermal layers and moves upward to hydrate cells in the stratum corneum, eventually being lost to evaporation. Occlusive moisturization, then, prevents the dehydration of the stratum corneum.
Much more is now known about the epidermis, and in particular, the stratum corneum. The “bricks and mortar” model suggests that its role is as an active membrane. Loss of intercellular lipids, i.e., the ceramides, cholesterol and fatty acids that form the bilayers, damages the water-barrier function. The stratum corneum then calls into action repair mechanisms. Dry skin is noted when the moisture content is less than 10%, and there is a loss of continuity of the stratum corneum.
Occlusives are substances that physically block TEWL in the stratum corneum. Petrolatum in a minimum concentration of 5% is the most effective occlusive followed by lanolin, mineral oil, and silicones such as dimethicone. Petrolatum is widely used as a classic moisturizer. Lanolin, a complex structure of esters, diesters, and hydroxy esters of high molecular weight, lanolin alcohols, and lanolin acids, is also widely used and quite effective.
Humectants attract water when applied to the skin and theoretically improve hydration of the stratum corneum. However, the water that is drawn to the skin is trans-epidermal water, not atmospheric water. Continued evaporation from the skin can actually exacerbate dryness. Humectants include glycerin, sorbitol, urea, alpha hydroxy acids (i.e., lactic acid) and other sugars. NMF is made up of a mix of low molecular weight soluble hygroscopic substances including lactic acid, pyrrolidone-carboxylic acid, and amino acids. This naturally mixing compound is thought to be a major player, keeping the horny layer hydrated and flexible.
Manufacturers’ attempts to include the above humectants into moisturizers do not always produce a beneficial effect. High concentrations of propylene glycol and urea can be irritating. Pure mixtures of amino acids are useless as moisturizers. Pure solutions of glycerin are ineffective and propylene glycol by itself is irritating. In addition to their humectant properties, urea and lactic acid are keratolytic. Urea is a humectant in lower concentrations (10%), but in higher concentrations (20-30%) it is mildly keratolytic by disrupting hydrogen bonds or epidermal proteins. Alpha hydroxy acids, such as lactic acid or glycolic acid, appear to increase the cohesion of the stratum corneum cells, thereby reducing roughness and scaling.
|Class Action||Mechanism of Ingredients||Example||Indication||Indication Side Effects|
|I. Occlusive||Physically block TWEL||Petrolatum
Prevention of Irritant
|Messy, Cosmetically Unacceptable, Folliculitis, (Mineral Oil) Comedogenic Contact Dermatitis,(Lanolin)|
|II. Humectants||Attract water to stratum corneum
Alpha hydroxy acids
|Irritation (Urea, Lactic Acid)|
|III. Emollients||Smooth Skin by filling spaces between skin flakes, with droplets of oil||Cholesterol
|Decrease skin roughness||Not always effective|
|IV. Protein Rejuvenators||Claim rejuvenate skin by replenishing essential proteins in skin||Collagen
|Skin Rejuvenation?||Unlikely to work
Protein too large to cross epidermis
Emollients are used to soften and smooth the scales of the skin, which help reduce rough, flaky skin. They are also occlusive agents: substances that provide a layer of protection that helps prevent moisture (water) loss from the skin.
Mechanisms of action
Emollients smooth skin by filling spaces between skin flakes with droplets of oil, and are not usually occlusive unless applied heavily. When combined with an emulsifier, they may help hold oil and water in the stratum corneum. Vitamin E is a common additive, which appears to have no effect, except as an emollient. Likewise, other vitamins, e.g., A and D, are also added with questionable effect. Examples of emollients include mineral oil, lanolin, fatty acids, cholesterol, squalene, and structural lipids.
Long chain saturated fatty acids and fatty alcohols are commonly used in topical pharmaceuticals and cosmetic formulations. They exert their benefits through effects on the skin barrier and on permeability. Examples include stearic, linoleic, linolenic, oleic, and lauric, which can be found in palm oil, coconut oil, and wool fat. Fatty acids and fatty alcohols can change the properties of intracellular lipids or the stratum corneum. Medium chain saturated hydrocarbons or longer chain unsaturated hydrocarbons are the most effective. Essential fatty acids (i.e., linoleic and alpha-linoleic acids) influence skin physiology and pathology via their effects on skin barrier functions, eicosanoid production, membrane fluidity, and cell signaling.
Structural lipids, i.e., intracellular lipids comprising multilamellar, which are located between stratum cornea cells, are felt to play a considerable role in the water-holding potential of the stratum corneum. Ceramide is a major component of the inner cellular lipids and plays a major role in generating multi lamellae architecture. Several pseudo ceramides have been synthesized (the natural form is still too expensive) and clinically shown to be effective in preventing and improving dry skin.
Moisturizers containing collagen and other proteins, i.e., keratin and elastin, claim to rejuvenate the skin by replenishing its essential proteins. This is unlikely to occur since these protein molecules are too large to penetrate the dermis. Protein additives may provide temporary relief of dry skin by filling irregularities in the stratum corneum. Like emollients, when they dry they shrink slightly, leaving a protein film that appears to smooth the skin and stretch out some of the fine wrinkles.
Indications for emollients include dry skin, i.e., xerosis or as a result of metabolic conditions, such as renal insufficiency and diabetes; atopic dermatitis; ichthyosis vulgaris; irritant contact dermatitis and prevention; nummular dermatitis; psoriasis; skin protection, i.e., frequent hand washing; and dermatoheliosis.
Differences between male and female skin
The skin on a man compared to a woman is significantly different. The ability to grow a hair fast, for instance, a mustache or beard, is a very obvious distinction. In structural difference, other samples are skin thickness, collagen density, loss of collagen as we age, texture and hydration.
Skin varies with location (climate/environment), age and gender of the individual. Androgens (i.e. testosterone), causes an increase in skin thickness this accounts for the fact that a man’s skin is about 25 percent thicker than of a woman. A man’s skin thins gradually with age, while the thickness of a woman’s skin remains constant until about the age of fifty. After menopause, her skin thins significantly, which continues while aging.
Collagen and elastin Density
Men have a higher collagen and elastin density than women; this is the ratio of collagen to the thickness of the skin. Researchers believe that the higher collagen density accounts for why women appear to age faster than men of the same age. When considering intrinsic (genetically-programmed) aging of the skin, it is suggested that women are about 10-15 years older than men of the same age. Men are most affected by sagging skin combined with puffy eyes and dark circles that make them look tired.
Loss of Collagen
Men and women lose around one percent of their collagen per year after 30. For women, this goes significantly faster in the first five years after menopause then slows down to a loss of two percent per year.
The male skin texture rougher, and the Stratum Corneum is thicker. There is a difference in the composition of sebum and its production. After puberty, sebum production is greater in males than in females, which is attributed to androgen secretions and accounts for why males have longer lasting acne. The cells in a man’s sebaceous glands have more positive receptors for androgens, which explains why they produce more sebum. Men have more active sebaceous glands, and therefore more pores, than women. Both their sebaceous glands and their pores are larger than those of women. Sebum production is double that of women, male skin is oilier and shinier than female skin. As a result, its pH is lower than that of female skin and is prone to impurities and acne.
Puberty stimulates the appearance of facial hair in men and sweat secretions. Males have more Lactic Acid in their sweat, which accounts for a lower pH (.05 lower) when compared to female sweat. Men sweat at least twice as much as women and are more prone to sweating, which is stimulated by an increase in body temperature. However, male skin appears to be better hydrated than women’s. Perhaps the excess sweating and production of Lactic Acid, a known natural humectant for the skin.