Your skin is the largest organ in your body. It’s a big deal. People spend billions of dollars each year on moisturizers, lotions, and potions to keep the skin soft and moist…but it hasn’t always been this way! Skin moisturizers are a relatively new invention in human history. Not so long ago, people didn’t know how to keep their skin moist, and they even thought it was normal for skin to be dry and flaky.
How did we get here? How did people figure out that moisturizing the skin keeps it healthy? And if we hadn’t figured out what dry skin is, how can we figure out what dry skin needs?
The answer is that modern cosmetic science has discovered some pretty fancy stuff about what happens at the surface of the skin: our outermost layer of cells, called the stratum corneum. And here’s a secret: moisturizer works because of basic biology. The stratum corneum is held together by a special molecule…and guess what? You can put more of that molecule on with moisturizer!
As you may have guessed from the name, this molecule is called “ceramide.” It’s a lipid that forms a barrier across cell membranes to keep water inside the cell.
Moisturizer is big business. Companies spend millions of dollars each year convincing consumers to buy expensive products on the premise that they will make skin look better, feel better and slow the aging process. Many of these products contain scientifically-proven ingredients that do exactly what they promise. Others are nothing more than oil in water, or water in oil.
But what is moisturizer? How does it work? And why is it so effective at improving appearance and health of skin?
The answer to all of these questions lies in understanding the content of skin, its structure and function, and how it changes as we age (and also with environmental factors like sun exposure).
If you have dry skin, chances are you’ve used a moisturizer. But why do we need a moisturizer? What causes dry skin in the first place? This article explores the science of what moisturizers are, and how they work (or don’t work) to help your skin.
Dry Skin Explained
Dry skin can be caused by many things, including:
* lower levels of oil in the skin’s surface layers
* lower levels of skin cells
* using harsh cleansers, soaps and detergents that strip oil from the skin’s surface
* environmental factors such as wind or dry air
* conditions such as eczema or psoriasis that reduce the skin’s ability to retain moisture
When your skin is healthy, it has a protective layer (known as the acid mantle) made up of natural oils (sebum) and sweat. This layer helps keep moisture in, and protects your body from bacteria, dirt and other foreign substances. When this layer is disrupted through over-cleansing or exposure to harsh environmental factors, dryness can result. Dryness will cause your top layer of cells to become flaky and peel away. If left untreated, dryness can lead to more serious
Ever wonder why your skin gets dry, or how moisturizers work? We’ll give you the 411 on dry skin and share some tips to help keep your skin moist, supple, and healthy.
Dry Skin: What Is It And What Causes It?
Your skin is a waterproof, flexible protective covering for your body. Its main components are protein, fat, and water. Dry skin occurs when the fats and oils that keep moisture in and irritants out become depleted. At its worst, dry skin can become itchy, red, flaky, or cracked. In milder cases it may just feel tight or look dull.
The outer layer of your skin is made up of dead cells that are constantly being shed (this process is known as desquamation). When the weather gets cold or dry (or both) the water in these dead cells evaporates more quickly than it can be replaced by new cells rising up from below. The result is a loss of flexibility and elasticity in the outer layer of your skin. This condition is known as xerosis cutis. Dry skin can also be caused by excessive washing with harsh soaps or detergents.
In order to understand how moisturizers work, it is first necessary to understand a little bit about dry skin. The outer layer of your skin is called the stratum corneum. It consists of dead cells that are filled with keratin, a tough protein. This layer protects your body from the environment. The cells in this layer are constantly being shed and replaced by new cells from below.
The stratum corneum does not contain blood vessels or nerves, so it depends on the layers below for nourishment and hydration. If your skin is too dry, the dead keratinized cells can crack and break, leading to irritated or itchy skin and sometimes infection. Even normal skin has some cracks between these cells which allow water to escape from your body. When your skin is moist, these cracks are sealed shut.
Chronic dry skin is most often due to environmental conditions such as low humidity (as in winter) and very hot water (bath or shower). Soap can strip natural oils out of the top layers of your skin leaving it dry and cracked. Overzealous use of scrubs can also irritate the stratum corneum leading to dryness. Dry skin can also be caused by certain medical conditions such as eczema and psoriasis as
The skin is a complex organ with many functions. In addition to providing protection and synthesizing vitamins, the skin performs an important role in regulating water balance. While there are many different types of dry skin conditions, all share the ability of the skin to prevent water loss from the body.
Dry skin occurs when the outermost layer of the skin (the epidermis) loses water or is unable to retain water due to changes in its structure. Treating dry skin requires understanding what causes it and then using appropriate moisturizers in a regular fashion.
The Epidermis and Stratum Corneum
The epidermis is composed of multiple layers of cells that constantly regenerate. The outermost layer of the epidermis is called the stratum corneum (literally “horny layer” in Latin). This layer contains dead cells that are constantly shed from the epidermis as new cells are formed by cell division in deeper layers of the epidermis. These dead cells are flattened, somewhat hard and full of proteins called keratin (Figure 1). This keratin forms an effective barrier to water loss from the body through evaporation from beneath this layer of cells.
This horny layer is further protected by natural oils produced by sebaceous glands located at hair
Your skin is your body’s largest organ, weighing in at about nine pounds on average. It covers an area of about 20 square feet, and it is only 0.1 inch thick. Your skin is made up of three layers: the dermis, epidermis and hypodermis.
The dermis is the thickest layer of your skin, where you find blood vessels, hair follicles, sweat glands and nerve endings. The epidermis is where you will find melanin (the pigment that gives our skin its color). The hypodermis is where your fat cells are stored.
Even though it’s just one-tenth of an inch thick, your skin contains almost every type of cell found in the human body: epithelial cells (found in the outer layer of tissue), connective tissue cells that are important for wound healing, lymphocytes (white blood cells that fight infection), macrophages (cells that fight infections) and mast cells (involved in allergic reactions).
Your skin keeps you safe from the outside world by holding moisture inside your body and keeping germs out. It also protects you from UV rays and regulates your temperature. But your skin can’t keep working forever without some help: Anything from sun exposure to a