Many of the recipes in this book go on our skin, so it is probably a good idea to learn a little about how the skin is structured and its basic functions. Having a better understanding of what makes up the different layers of our skin will provide tremendous insight as we select ingredients for our recipes, especially when we are considering specific skin types and conditions.
Our skin, also known as the integumentary system, weighs between seven and eight pounds. If it were stretched out, it would measure approximately sixteen to twenty-two square feet. Its complex and dynamic functions are essential to our overall health and wellness.1
The skin has seven basic functions:
1. It protects
a. our internal organ tissue from the environment by providing a kind of cushion layer against sudden impacts, abrasion, and bumps,
b. our bodies from dangerous UV light,
c. our bodies from rapid evaporation of water,2 and
d. our bodies from environmental pathogens.
2. It regulates our temperature.
3. It performs sensory functions via nerve cells, so we can feel temperature, pressure, and pain. There has even been some recent research showing how our skin can recognize scent, through the presence of olfactory nerve cells.3
4. It synthesizes vitamin D.
5. It excretes sweat and gases.
6. It absorbs.
7. It temporarily stores fats, sugars, vitamins, and salts.4
When we are formulating our skincare recipes, we generally want to keep all these functions in mind and specifically want to think about how and what the skin absorbs and how each of the ingredients we choose can offer support to our skin’s protective barrier and overall appearance.
Our skin absorbs components of whatever products we rub, massage, lather, and spray on it and then deposits what it absorbs directly into our bloodstream. There are two absorption paths that we focus on in our recipes: (1) hair follicles and (2) the lipid matrix, which can be described as the complex fatty mortar that fills the spaces in between the skin’s cells. Both of these routes eventually connect with capillaries, veins, and arteries that then carry the molecules of what was absorbed all over the body.
Most skin conditions stem from a weakened or damaged lipid matrix, resulting in dry skin, acne, sensitive skin, and aging skin. When the complex cocktail of fatty acids and other substances like sterols, esters, and vitamins that compose our lipid matrix gets thrown off balance and starts to deteriorate, pathogens and microbes can enter our bodies more easily and make us ill.
Another vitally important role of our lipid matrix is to prevent our body from losing water. The official term for this is transepidermal water loss (TWL). Proper water levels in our body and our skin are also essential to maintaining our overall health.
The first few layers of our skin are made up of what’s called “dead” cells, meaning they contain no water and have been completely transformed into proteins. They make up our “horny” layer and add a certain level of protection against the environment. These cells are stacked in a way that resembles a stone wall, without the mortar. The lipid matrix isn’t present here because these cells need to slough off to make room for the new cells that are busy generating in the bottom layers of the skin. It’s these upper layers that we want to focus on when we are making exfoliants and masks; we want to push along the process of sloughing off dead cells in order to make room for the new ones.
Sandwiched between this horny outermost layer of our skin and the layer where the cells are actually generated through mitosis (cell division) is an area of the epidermis (our skin) where the lipid matrix is rich and active. And it is this layer that we want our beautiful farm-fresh ingredients to make contact with.
Feeding the lipid matrix is really at the core of each of our recipes. We look at each ingredient, consider its unique chemical composition, and try to match it up with what we know makes up the lipid matrix, like fatty acids, vitamins, sterols, and esters. Supporting and nourishing our lipid matrix will greatly improve the overall health and appearance of our skin.
The area below our epidermis, where the lipid matrix resides, is called the dermis. And this is important for us to know because it is where collagen (the protein fibers that help give our skin shape) and elasticin (the protein fibers that support our skin elasticity) are actually synthesized and where we find our blood vessels. Our goal, then, is to try to direct our ingredients to penetrate down to this layer and ultimately make contact with our bloodstream and support and nourish the production of collagen and elasticin.
Certain skin types and conditions can often be traced directly to imbalances in our lipid matrix and in our skin microbiome. The skin microbiome is the protective film that covers the horny layer of our skin and is made up of a unique blend of our sebum (the oily substance secreted by our sebaceous glands, which are attached to our hair follicles), our sweat, and millions of microorganisms, or microbiota (bacteria), that live on the surface of our skin.
Let’s look at a few different skin types and consider the function of the lipid matrix and skin microbiome and the selection of particular ingredients.
Dry, Aging, and Mature Skin
Feed the lipid matrix with oils rich in essential fatty acids (EFAs), sterols, esters, and vitamins. As we age, our lipid matrix deteriorates and loses the essential components that help prevent water loss and infections. Oils made from hemp seed or avocado can provide the fatty acids and the nutrients crucial to keeping the lipid matrix fluid and balanced, thus slowing down the formation of fine lines and wrinkles and inhibiting flaking and inflammation.
Sensitive and Reactive Skin
Avoid stripping the skin microbiome with harsh cleansers, and opt instead for oil cleansers and gentle masks. Choose oils rich in gamma-linolenic acids, like borage and evening primrose, which reduce inflammation and soothe irritation by strengthening and plumping up the lipid matrix to keep out allergens and bolster the strength of cellular membranes.
Oily Skin
It may seem counterintuitive, but one of the best ways to balance an overproduction of sebum (the oils our sebaceous glands excrete) is by actually using oil. A good choice would be either jojoba or argan. Overcleansing, even with a soap as gentle as castile soap, may strip too much of the microbiota and trigger an excess of secretion from the sebaceous glands. Honey washes and gentle white clay masks can draw in moisture without stripping natural oils, while neutralizing bacteria that may cause infections (blemishes).
Our ingredient charts (beginning on page 68) provide a wealth of information and detail on many ingredients and break down their essential fatty constituents and nutrients. The charts will help you formulate recipes for specific skin types and conditions and draw on an array of different fatty acids, nutrients, and other vital components that can heal and support the health of your skin.