Scientific skin care skin moisturizing article
Human body water accounts for about 70% of body weight, and human aging is a process of losing water. The water content of the cuticle of the skin is about 10-20%, and when the moisture is less than 10%, the skin will become brittle, easy to crack, and it will dry, desquam and fine lines. Moisturizing is to lock in the moisture in the stratum corneum, maintain the water content of the stratum corneum, and maintain the supple state of the skin's appearance.
Human reservoir - dermis
The moisture content of the dermis is as high as 60-70%, the water content of the epidermis layer is 20-30%, and the water content of the reaching the stratum corneum is 10-20%. The moisture content of the skin from the dermis to the stratum corneum gradually decreases.
The dermal matrix contains mucopolysaccharides such as hyaluronic acid and chondroitin sulfate that bind to water to prevent water loss.
How human skin is naturally moisturized
Physiological function of the stratum corneum
The moisturizing of the stratum corneum plays an important role in the appearance and physiology of the skin, relying on a variety of factors, such as the humidity of the external environment, the structure of the stratum corneum, the composition of lipids or proteins, barrier function, the concentration of regulatory substances or natural moisturizing factors.
Sebaceous film
The sebaceous membrane is mainly composed of interkernocyte lipids, sebum and sweat secreted by sebaceous glands.
Transcutaneous moisture loss is determined by the lipid properties between keratinocytes and is accompanied by changes in humidity and temperature outside, with healthy skin losing less than 500 g of moisture per day.
Natural Moisturizing Factor (NMF)
Natural Moistruring Factor (NMF)
It is a general term for substances that exist in the stratum corneum that can bind to water. Accounting for 20-30% of the dry weight of cells, the water content in the stratum corneum can be maintained by adjusting the stored water, including amino acids, pyrrolidone carboxylic acid (P.C.A), lactate, urea, uric acid and other low molecular weight substances.
Aquaporin (AQP)
Aquaporin 3 (AQP3) is a major aquaporin expressed in the skin and has the function of a small molecule substance that crosses membranes. Moisture, glycerin, and triglycerides in the sebaceous glands can be brought into the epidermis from the circulation, thereby ensuring the moisture of the epidermis and playing an important role in the barrier repair and moisturization of the epidermis.
The cause of dry skin
Poor skincare habits
For example, the daily use of moisturizers, or the number of masks applied too many times and too long increases the permeability of the skin, but the moisturizing products are not used in time to lock in moisture, destroying the barrier of the stratum corneum.
Bad habits
If the washing force is too large, the time is too long or the use of powerful clean oil control acne products, bathing with alkaline soap, often using hot baths with too high temperatures, including showers, etc., it is easy to destroy the normal lipids on the surface of the skin and aggravate the dryness of the skin. wait.
environmental factors
Such as cold, dry, frequent use of air conditioning, windy weather, etc., can aggravate the dry skin.
Disease or medication cause
Patients with certain conditions, such as hypothyroidism and uremia, are prone to dry skin; taking certain special medications, such as taking lithium preparations or retinoids, can cause dry and scaly skin.
Mental stress
Excessive mental stress affects the skin's self-repair and aggravates the dryness of the skin.
age
Age factors can not be ignored, the skin gradually ages with age, the repair function is impaired, the repair speed is slow, and the synthesis of natural moisturizing factors in the skin is also greatly reduced, resulting in a decrease in the skin's water retention ability, so it is easier to dry.
heredity
Some people are born with dry skin, so they are born with dry skin.
How to hydrate and moisturize
Hydration – a prelude to moisturizing
Lotions, sprays and masks can hydrate the skin, directly replenish the moisture required by skin cells, not only moisturize the surface of the skin, but also increase the water content of the stratum corneum, increase permeability, and better absorb subsequent nutrients.
Choose a moisturizer
Moisturizers contain three active ingredients: moisture absorbents, blocking agents and emollients.
Moisture absorbers can promote moisture from the dermis into the epidermis, and can also absorb moisture from the external environment, such as glycerin, urea, propylene glycol, etc.;
Blocking agents form oil films on the surface of the skin to prevent moisture from evaporating, such as petroleum jelly, mineral oil, silicone, etc.;
The ingredients in the emollient can fill the intercellular fissures in the keratinocytes, leaving the skin soft and smooth, containing a group of alcohols and esters.
"Bionic" moisturizer
Biomimetic moisturizers such as natural moisturizing factor (NMF), ceramides, hyaluronic acid, etc. can replenish the intercellular lipids of the stratum corneum, repair the skin barrier, and enhance the moisturizing ability.
How to moisturize scientifically?
Don't over-cleanse your skin, but choose a moisturizing cleanser that suits you, such as skin type, age, season and environment.
Refreshing moisturizer/gel with less oil in the T-zone of oily or combination skin in summer, moisturizer with less oil, moisturizer with more oil on the cheeks of winter, dry or combination skin; Particularly dry areas such as calves can optionally use highly moisturizing cream or ointment; Babies and the elderly have dry skin and a weak skin barrier, so moisturizers rich in oil and natural ingredients should be used.
Reasonable moisturizing is to maintain the proper moisture content of the stratum corneum, maintain the integrity of the epidermis layer and the barrier function of the skin, lock in moisture, and prevent moisture loss too quickly.
Daily need to drink more water, eat more vegetables and fruits, in a dry environment using humidifiers and other means to moisturize.