Exfoliation Basics

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From scrubs to enzymes & chemical peels, there are many options for exfoliation.

It can be confusing to understand the benefits of various ingredients and what type of exfoliating products to use. For example, did you know that a high quality, alpha or beta-hydroxy acid lotion is gentler on the skin and more effective than a scrub? Did you realize that exfoliation, if done correctly, gradually restores skin health and thickness?

Claims that exfoliation can thin your skin stem from a misunderstanding of skin physiology. Our epidermis naturally exfoliates; if not, we would have skin like alligators! Cell renewal slows as we age, and helping it along only thins the skin by a few cell layers, literally a microscopic amount, while the deeper skin benefits and can actually thicken. Since misconceptions usually arise from a misunderstanding of the basics, let’s start there.

The Epidermis: a cell making factory

The epidermis is the outer layer of the skin and houses 5 thin layers within it, each with a different function in the cell renewal process. Due to more frequent interaction with environmental elements than any other organ, the skin requires a system of continual repair and renewal. Skin cells are shed at the topmost layer, the stratum corneum, making way for new cells gradually rising from the bottom of the epidermis upward. The epidermis is constantly manufacturing new cells and shedding old ones off the surface (at a rate of about 40,000 a day).

This process slows with aging. In youth, cells turn over weekly and in our 20s monthly; then in our 30s the process slows down. Cell turnover in the 40s/50s may be every 6-8 weeks or slower, depending on the condition of the skin, amount of sun damage, hormonal factors in women, and genetics. The result is that skin can appear dull, lined, flaky, or congested. Problems like adult acne, milia or sensitivities can develop. As cell turnover continues to slow through the 60s and beyond, dry skin is often a chronic issue.

The lipid barrier & the acid mantle

It’s all about balance. You do need a certain amount of dead skin cells (corneocytes) as a barrier, along with lipids and natural acids present in sweat for protection, the main function of the stratum corneum. A healthy acidity (5-5.5pH) protects from bacterial infection and lipids prevent water loss in the skin. Corneocytes and lipids work together to protect us from the elements.

It is excess dead skin that is the problem. Adult acne often results from overly stimulated oil glands due to hormonal fluctuations combined with excess dead skin blocking oxygen and sebum flow in the pores.  Alternately, for those with dry skin, too many dead skin cells can slow cellular functions like lipid replacement and turnover rate, leading to chronic dryness. The skin’s natural ability to moisturize itself diminishes even more, and at the surface, moisturizers don’t penetrate as well, creating a double-whammy that leads to chronic dryness. If your skin has depleted lipids, it loses water to the air more rapidly than normal and becomes more sensitive, often with diffuse redness, and is prone to irritation and allergic reaction.

Scrubs: “NOTHING SO STRONG AS GENTLENESS” 

Skin scrubs only on the most surface dead skin cells. Some scrub mediums have microscopic edges that can irritate and cause redness. To quote St. Francis, there’s “nothing so strong as gentleness.” If you like scrubs, look for those with jojoba or clay beads, which are rounded, or buffing powders made of coconut milk or rice. (Jojoba, clay, rice and milk powders break down, which is better for both your skin and the environment). For tough, severely dry, or sun-damaged skin, a gentle scrub can be beneficial as a prep, to remove excess surface dead skin, so that next-step ingredients can work better. An exfoliating powder is a great way to boost the efficacy of an enzyme mask. Most scrubs should be used no more than three times a week, while buffing powders are gentle enough to be used daily and some double as a cleanser.

Enzymes

Enzyme peels are the perfect alternative for sensitive skin types, as long as you aren’t allergic to the fruit, plant, or animal from which they are derived. Enzymes are dormant until stimulated by heat, such as steam or hot towels, but some are formulated to awaken from normal body heat and activated by massage. So if you’re using an enzyme at home, massage it in, and boost it by taking a hot bath. In a professional facial treatment, enzymes are typically activated by steam and are left on the skin for about 10 minutes. The fresher the enzyme product, the better it will work to break down dead skin so it can more easily be shed. Like alpha and beta hydroxy acids, enzymes do not affect healthy tissue. Although their actions are more superficial than acids, enzymes from papaya, pineapple, and pumpkin are natural sources of vitamins A, C and other antioxidants.

AHAs & BHAs

Alpha and beta hydroxy acids in low percentages have been shown to effectively and gently speed cell turnover to restore healthy skin functions. The benefits are seen within days. This is because both AHAs and BHAs dissolve the bonds between dead skin cells, to allow for even shedding over the course of 24 to 72 hours after application.  Reduced dead skin means better absorption of moisture and active ingredients. Because these acids penetrate into the dead skin layer, they are more effective than scrubs, but they can cause sensitivity and are not recommended for rosacea-prone skin. 

AHAs and BHAs, at strengths used in cosmetic products and superficial peels, target only dead or damaged cells and do not harm healthy skin cells in the deeper epidermal layers. Both have also been heavily studied in the treatment of post inflammatory hyper-pigmentation (brown or red spots that remain after acne or a wound has healed). These acids target damaged cells, which are the cause of uneven skin tone.

Common alpha-hydroxy acids in skincare are glycolic, lactic, mandelic, malic, and tartaric. All are derived from plant or milk sources and are water-soluble. Glycolic acid is the most popular AHA, because it penetrates the stratum corneum more easily than other acids due to its small molecular size. Glycolic increases moisture-binding abilities, and lactic assists healthy lipid production, improving the skin’s barrier. Although AHAs do not penetrate to the dermis, glycolic has been shown to trigger a collagen response deep in the skin, to improve skin structure. The result is smoother, healthier skin.

Salicylic acid, the primary BHA, is oil-soluble. This means that salicylic can penetrate the follicle where oil glands reside and exfoliate any dead skin accumulation inside the pores, unclogging and clearing the skin. It is often used in peels and is a common ingredient in acne systems, along with ingredients like benzoyl peroxide and retinoids.  Salicylic is derived from willow and has anti-inflammatory properties. It allows topical antibiotics and other ingredients absorb into the pores and work more effectively.

Dosages & Use

For salicylic acid, start with 1% and increase to 2% if needed. For glycolic, 4 to 10% is best. When applying AHA or BHA products, always avoid sensitive areas near the eyes, nose, and mouth, unless it is specifically formulated for the eye area.

If used in the proper dosage, AHAs and BHAs do not thin the skin. Keep in mind, these acids are only working in the stratum corneum layer of the epidermis, which is less than 7% of total skin thickness. The general effect of these products is healthier, stronger skin, as a result of normalized lipid production and collagen stimulation.

AHAs can have antioxidant effects, but must be used in combination with a broad spectrum sunscreen. Both alpha and beta hydroxy acids can cause some sun sensitivity. I recommend using a sunscreen with at least 7% mineral block (zinc oxide or a combination of zinc and titanium), and remember to reapply when you’re out for an extended time. Keep in mind, recent studies show that 85% of premature aging is due to UV damage. Before trying a new AHA product, always patch test any product if you have a history of contact dermatitis and allergies, and follow package directions for application.

~Ivy Nowosad, LE

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