What does “skin renewal” mean?
Nothing and everything: it depends on the context and who is talking. What do you need to do to renew your skin? Nothing. Your skin renews itself all the time.
So what does the skin care industry mean by skin renewal?
Generally, they mean that you should peel your dead skin cells off. But those dead skin cells, which make up the stratum corneum, are what make your skin impermeable to water using chemicals like ceramides.
If we want to be more specific in defining what renewal means, we first need to understand what is going on in the anatomy of the skin.
The skin is made of two “sections”: the epidermis and the dermis. The subcutaneous fat, which underlies the dermis, also affects the way the skin looks and the shape of the face.
Figure. Skin structure showing epidermis, dermis and hypodermis. Notice the blood vessels and nerve fibers that connect the skin with the rest of the body.
The stratum basale is primarily made up of basal keratinocyte stem cells, which are the stem cells of the epidermis. They divide to form the keratinocytes of the stratum spinosum, which migrate to the surface. Other types of cells found within the stratum basale are melanocytes (pigment-producing cells), Langerhans cells (immune cells), and Merkel cells (touch receptors).
The keratinocytes change in shape, structure and biochemistry as they are being pushed outwards by new cells produced by the basal layer. Keratinocytes mature and die in a very special way, in a progression that will form an almost impermeable layer of dead cells. Many chemical reactions happen in this gradual process, and one of them is the formation of ceramides from fatty acids present in the keratinocytes. One lesson here is that if we want ceramides in our epidermis we should feed our skin plenty of unsaturated fatty acids.
Melanocytes are cells located in the epidermis, but they have more in common with the brain (they originate from the same embryonic tissue) than with the epidermis itself. Their function is to protect the skin from UV light. The melanocytes by themselves will not be sufficient to protect your skin from the sun. To delay skin aging and prevent skin cancer you will need to supply further UV blocking.
Your job is to facilitate the job of the epidermis by covering the epidermis with a cream, lotion or gel that retains water. You should also make sure that the cracks in the epidermis, visible and otherwise, are taken care of. Do we need to supply ceramides to the skin as well? Not really. If our skin has the required nutrition, including unsaturated fatty acids, it will be manufacturing and modifying a variety of ceramides that skin care products can’t hope to match. However, if for some reason you have not been doing a great job of supplying nutrients to your skin, you may need to supplement the skin barrier with a ceramide substitute like petrolatum or lanolin.
Section of the epidermis showing the five layers. You can see individual, nucleated cells in the two bottom layers and how the cells lose structure as they mature to form the more superficial layers of the epidermis. Structural changes are accompanied by changes in chemical composition. Skin cells change shape and structure as they transit the different layers of the epidermis. Cornified cells are dead cells, but together they make the stratum corneum that prevents water loss and the entry of microbes.
Just as the epidermis is formed mostly by cells (alive or dead), the dermis is a matrix made of mostly proteins and polysaccharides, with scattered cells (fibroblasts) that synthesize these macromolecules. Many of the changes we see as skin ages reflect changes originating in the dermis, so it is a good idea to look after the dermis too. You may think that the epidermis, in charge of protecting the underlying tissues, would not let anything go through. But the epidermis is far from impermeable. When intact and healthy it will protect from water loss, but this does not mean that chemicals cannot penetrate. The skin of a 50 year old is no longer intact and will allow water to escape and many more chemicals get through.
So, you want smooth skin?
A peel may improve the way your skin looks and feels by removing the upper layers of the epidermis. These are dead cells, but they are the ones that are providing you with a barrier against water loss. A peel also allows damaging UV light into the deeper layers of your skin. Sometimes the end result of a peel is scarring, hyperpigmentation or hypopigmentation.
Exfoliators remove the top layer of dead skin cells to make the skin feel smooth. There are three ways of exfoliating your skin: physical scrubs (which involve a gritty texture that can come from sugar, salt, crushed nuts, crystals used in micro-exfoliation, etc.), chemical peels, and enzymatic peels. You need to be cautious with exfoliation because you can cause permanent damage to your skin. Mistreatment can lead to scars and/or hyperpigmentation.
Skin Actives has products that use these three exfoliation methodologies without resorting to brutal treatments. The skin doesn’t need to be treated like an old wall in need of resurfacing by sandblasting. The skin is not an inanimate object but a living organ, and our goal at Skin Actives is to preserve your skin’s health.
Our Alpha Beta Exfoliator is a mild form of chemical peel that is safe to use on the face, décolleté and hands weekly without problems. When used as directed, it will provide an invisible peel, and you will have satisfyingly smooth skin without down time or visible peeling.
Pumpkin Enzyme Peel is great for more sensitive skin types. This is a natural, gentle enzyme peel that leaves the skin cleansed and silky smooth. You will see no peeling, but your skin will feel smooth and look great.
Skin: dermis and epidermis. How far does a peel go?
A peel is a controlled chemical burn of your skin that can go from superficial (top layers of the epidermis) to deep (halfway through the dermis). If you go any deeper, you will end up in the emergency room.
Chemicals peels are usually made of weak alpha hydroxy acids (ie: lactic or glycolic) dissolved in water. These acid solutions (often called “chemical peels”) will break down the proteins in the most external layers of the skin when used appropriately and with caution. If used without great caution they will burn the skin. As the solution denatures the proteins in the upper layers, it penetrates further and further, eventually reaching the inner layers of the epidermis and even the dermis. The acidity of the peel and the time until neutralization occur are factors in how far the peel will penetrate. Other chemicals that are used in the peels may act in different ways, but their action usually involves denaturing proteins and killing cells. Please remember: an acid peel is a controlled chemical burn. It must be controlled carefully.
Lactic or glycolic?
Does it matter which acid you use? Not much. What matters is how acidic the peel is. The desired pH can be obtained with many different acids, all of them suitable for use on the skin. The pH depends on the concentration of the acid, in molecules per unit volume, and the pK of the acid (how likely it is to release its protons). This can be slightly confusing to non-chemists because the molecular weight of glycolic acid is lower, so you get more molecules per unit of weight.
Don’t play with fire (or acids)
Glycolic 70% will burn your skin. I am confident working with it because I have decades of experience in a laboratory and the necessary tools to deal with strong acids. It is concerning that solutions claiming to be 70% glycolic acid are readily available for purchase online.
Why would people risk “burning, dermatitis or rash, swelling, pigmentary changes, blisters or welts, chemical burns” by buying and using such a solution? And why would an honest seller risk breaking the law?
Dermatologists are allowed to use peels with a pH as low as 0.6, and may even add dangerous chemicals like phenol in order to kill cells deep within the skin. These doctors have very high insurance premiums because peels can go terribly wrong. They also have an office where medical emergencies can be managed appropriately.
Your skin renews itself, so why push for more?
There is no need to push for skin renewal, unless you have very good reason, like acne.
Pores can get clogged with sebum, keratin, and dead cells. This results in an environment lacking in oxygen and favorable to the growth of the acne bacterium, Propionibacterium acnes. These products of bacterial metabolism cause the inflamed pimples known commonly as acne. This is a real problem and one that adequate skin care can help to prevent and correct. A comedo may be closed by skin (whitehead) or open to the air (blackhead). Being open to the air causes oxidization, which turns the lipids in the top of the ‘plug’ black or brown.
What can you do? Use a retinoid that will normalize keratinization and maintain epidermal integrity, like vitamin A. It will help to keep the skin healthy by switching on genes and differentiating keratinocytes (immature skin cells) into mature epidermal cells. There are many retinoids that are available, at Skin Actives we use retinyl acetate because it doesn’t cause unnecessary irritation.
What do people expect from a peel?
A good peel may cause no visible peeling or a light fluffy peeling. People tempted to “help” the process along by peeling the skin away may find that the skin revealed is raw and painful. People expect the skin to peel like a fruit. If their skin just gets red that is not enough.
People go to Ebay hoping to find a strong enough peel (70% glycolic acid, anyone?) that will peel their skin and show beautiful baby smooth and clear skin below. This is not how things happen.
To satisfy unrealistic expectations, a formulator may mix a mild acid with a chemical that will dry as a film so that you have something to peel off. The rest is a fantasy of a snake-like miracle peel in which an old, ugly skin peels off and a new, luminous glowing skin is being revealed, a sort of Cinderella story. Skin does not peel like this. The skin is not a film to be removed, but a structure made of cell layers.
-Dr. Hannah Sivak
**Note: We have recently removed the TCA peel for sale on our website due to concerns about potential chemical burns. It will still be available to licensed professionals. Please call 480-813-5633 or email Care@skinactives.com for more details.**