Every Skin Type Can Benefit from Exfoliating with an AHA or BHA Product
Perhaps no other part of a daily skin care regime can have the most immediate impact as gently exfoliating skin. Though there are a few different ways to exfoliate skin by far the most effective and well researched are alpha hydroxy acids (abbreviated to AHAs) and beta hydroxy acid (abbreviated to BHA). The benefits of using a well-formulated AHA or BHA can be apparent almost immediately, or at the very least, within a few days of use. Best of all, skin will continue to improve over time with ongoing use.
What Happens to Skin When You Exfoliate?
Most of my readers know about the importance of routine exfoliation, especially as far as using a well-formulated AHA or BHA product is concerned. The benefits are apparent within days of use, and skin continues to improve with ongoing use. But what's actually occurring when we apply an exfoliant? Well, it depends on what method of exfoliation you use! Generally speaking, the concept is that the top dead layer of normal skin (called the stratum corneum) sheds on a regular basis (thousands and thousands of skin cells every few minutes). This shedding process is due to the physiology of skin (how skin cells function and grow). New skin cells are produced in the lower layers of skin (the stratum basal layer); they then move to the surface, changing shape as they go, eventually dying and forming the outer, protective layer of skin. These dead skin cells on the surface are eventually shed as other cells from the lower layers travel to the surface and push them off, creating new "dead" layers of skin each time.
When we are young, skin cells are regenerated and turn over very quickly, about once a week for children. As we age, the rate of skin cell renewal changes ranging from about every three weeks through our teens and 20s, and then it slows as we age with the rate varying depending on the shape of skin (primarily meaning skin that hasn't been sun damaged or lost estrogen). Sun damage and stages of menopause reduces the ability of skin cells to reproduce in a healthy normal manner. Other than being smart about sun protection, considering various options of hormone replacement therapy, using skin care products laden with antioxidants and cell-communicating ingredients, or using a prescription retinoid such as tretinoin there isn't much else that can help improve cell production.
Separate from the regeneration of skin cells in the lower layers of skin, the shedding process on the surface of skin can also become inefficient, causing a build up of skin on the surface. Sun damage, loss of estrogen, dry skin, oily skin, and disorders such as psoriasis or rosacea can all effect how "smoothly" this natural exfoliation process takes place. When normal or healthy exfoliation doesn't happen, skin can become rough, scaly, thickened, discolored, and look more lined. Different forms of exfoliation help to remove the built up outer layer of skin to uncover a more normal, younger-looking layer hiding beneath. The most effective skin-care options for helping skin with this essential function are a well-formulated (meaning pH-correct) alpha hydroxy acid (AHA-the ingredient on the label would be glycolic acid, lactic acid, or gluconoalactone) or beta hydroxy acid (BHA-salicylic acid is the only BHA ingredient).Although salicylic acid is the only BHA option, there are a variety of AHAs. The five major types of AHAs that show up in skin-care products are glycolic, lactic, malic, citric, and tartaric acids. Of these, the most commonly used and most effective AHAs are glycolic and lactic acids. Both of these have the ability to penetrate the skin, plus they have the most accumulated research on their functionality and benefit for skin.
AHAs and BHA are available from several cosmetic brands, including my line. Using such products on a routine basis (which for some may mean once or twice daily, others every other day, or just twice per week) will make a remarkable difference in your skin's appearance, not to mention its healthy functioning.
What happens when we help the outer layer of skin function more normally? Your face can truly look younger! The best analogy I can think of is to compare it to the heels of your feet. Before you get a pedicure the built-up dead layer of skin on your heels looks dry, rough, discolored, scaly, and lines are pronounced. Once that layer is removed, and it can be removed fairly aggressively without damaging anything, your heels look much better. Moreover, once you apply moisturizer, which can now absorb better because it hasn't been blocked by the proliferation of overproduced skin cells, viola-you have "younger"-looking feet. I'm not suggesting we should be that aggressive from the neck up or on most parts of your body, but the same benefit of exfoliating the feet holds true for the face, you just have to be gentler than you are with your heels.
Enhancing skin's exfoliation process and smoothing its texture aren't the only benefits of using an AHA or BHA product. Not only do they make skin feel and look smoother, a good deal of impressive research has shown they provide protection from UV damage (provided you're routinely using a well-formulated sunscreen), sun-induced tumor development, noticeable improvement in skin structure, significant barrier repair function, and collagen stimulation (Sources: Molecular Carcinogenesis, July 2001, pages 152-160; Cancer Letters, December 2002, pages 125-135; Experimental Dermatology, January 2005, pages 34-40; Experimental Dermatology, April 2003, Supplemental, pages 57-63 and Dermatologic Surgery, May 2001, page 429.) All of these enhancements and the skin is neither compromised nor hindered in any way-now that's exciting (Source: Archives of Dermatologic Research, June 1997, pages 404-409)!
Those struggling with acne need to know that exfoliation of facial skin can also unclog pores by keeping dead skin cells from blocking the pore opening so sebum (oil) can flow more normally, which helps reduce blemishes and blackheads and it also allows antibacterial agents penetrate to where the bacteria causing acne is hiding.
(Sources for the above information: Archives of Dermatologic Research, April 2008, pages Supplemental S31-S38; Journal of Cosmetic Dermatology, March 2007, pages 59-65; Skin Pharmacology and Physiology, May 2006, pages 283-289; Food and Chemical Toxicology, November 1999, pages 1105-1111; Journal of the American Academy of Dermatology, September 1996, pages 388-391; Journal of Cosmetic Science, March-April 2006, pages 203-204; and European Journal of Dermatology, March-April 2002, pages 154-156)
AHAs vs. BHAThe primary difference between AHAs and BHA is that AHAs are water-soluble, while BHA is lipid-(oil) soluble. This unique property of BHA allows it to penetrate the oil in the pores and exfoliate accumulated skin cells inside the oil gland that can clog pores. BHA is best used where blackheads and blemishes are the issue, and AHAs are best for sun-damaged, thickened, dry skin where breakouts are not a problem (Source: Global Cosmetic Industry, November 2000, pages 56-57).
What glycolic, lactic, and salicylic acids all do is "unglue" the outer layer of dead skin cells, allowing healthier cells to come to the surface. You can expect almost immediate benefits from regular use of an AHA or BHA product which includes improved skin texture and color, unclogged pores, and moisturizers being better absorbed by the skin. Both AHAs and BHA affect the top layers of skin, and they help to improve the appearance of sun-damaged, dry, and/or thickened skin. Sun damage in particular causes the top layer of skin to become thicker, creating a dull, rough appearance on the surface of skin (Sources: Free Radical Biology and Medicine, May 17, 2008; International Journal Cosmetic Science, February 2005, pages 17-34; Archives of Dermatologic Research, June 1997, pages 404-409; Dermatologic Surgery, May 1998, pages 573-577).
What About Scrubs vs. AHAs and BHA?
Hands-down, using a well-formulated AHA or BHA product is preferred to routine use of a topical scrub. Because AHAs and BHA work through chemical processes, they can penetrate the skin and produce better results than cosmetic scrubs, which work only on the exposed surface of the skin. And, there is no risk that AHAs and BHA will cause you to lose too much skin. Technically, there is a drop-off rate, meaning the AHA and BHA will exfoliate just the dead or damaged surface skin and leave the healthy skin alone. This is the main reason why you will see a drop-off in performance when using an AHA or BHA product. The dramatic results in the beginning of usage (when the thickened, discolored layers of skin are being removed) seem much more impressive than the results from continued use. This is to be expected, and it is important to note that continued use of an AHA or BHA product is required in order to maintain skin's smooth, even-toned, healthy appearance.
How Do You Choose Which Exfoliant Is Best for You?As a rule, AHAs are best for normal to dry, sun-damaged skin because they only exfoliate on the very surface of skin rather than inside the pore. AHAs have research showing they improve collagen production and increase skin's moisture-binding ability. My 8% Alpha Hydroxy Acid Gel is a great option for all skin types and can be worn under a moisturizer without feeling heavy or layered with product.
BHA also exfoliates on the surface of skin but has extra properties that make it better for normal to oily or combination skin and especially blemish- prone skin. Salicylic acid can exfoliate inside the pore and it has anti-inflammatory and mild antibacterial benefits as well.
First-time users of a BHA product can begin with a 1% concentration of salicylic acid; those with oily to very oily skin and stubborn blackheads or blemishes should begin with a 2% concentration. Every Paula's Choice BHA product is formulated with additional soothing agents. Once you know the concentration you want to try, the only thing left to decide is whether you want a gel, liquid (2% strength only), or lotion texture.
Generally if you have normal to oily skin with moderate breakouts my gel is a great place to start. If you have very oily skin with moderate to severe breakouts the liquid is a must to try. If you have normal to combination skin the lotions are a wonderful option. Bottom line: which one to choose depends on personal preference more than any other factor and experimenting to see what works best for you.
How Do You Use AHAs or BHA?
You can apply an AHA or BHA product once or twice a day. Also, depending on your skin's sensitivity you can apply either of these around the eye area, making sure to keep them off the eyelid and away from the eye itself. Apply the AHA or BHA product after the face is cleansed and after your toner has dried (if you are using one). Once the AHA or BHA has been absorbed, you can apply any other product, such as additional moisturizer, serum, eye cream, sunscreen, and/or foundation. Whether or not you use a moisturizer with an AHA or BHA product totally depends on what type of skin you have, how it reacts to the AHA or BHA product, and what kind of base the AHA or BHA you're using comes in. Some AHAs and BHA come in moisturizing bases so an extra product isn't required. Important Note: The skin needs only one good exfoliant, and that's it. Overexfoliating will further irritate the skin, and the long-term effects of that are unknown.
Some people experience a tingling or slight stinging sensation when they use AHA or BHA products with appropriate concentrations and pH. Some people have had minor to severe flaking and redness. Minor, short term reactions can occur given the nature of AHAs and BHA. However, long-term irritation, redness, flaking, or patches of dermatitis are not healthy for the skin, and if any of these symptoms occur, you should reduce the frequency of application or consider a gentler (less concentrated) product. Observe your skin. If it gets very dry and flaky, use an additional moisturizer for a period of time until the skin calms down and gets used to the new level of exfoliation. If it gets red and irritated, use the product less frequently, though still regularly (perhaps once a day, or two or three times a week). If it still gets very dry and irritated, consider stopping altogether. Severe irritation is not the goal or the desired result.
What About Cleansers with AHAs or BHA Ingredients?
I never recommend cleansers that contain AHAs or BHA, for several reasons. First, if they are in a water-soluble cleanser, you run the risk of possible contact with the eyes, which can cause irritation. Second, AHAs and BHA work on the skin or the pores when they have been absorbed. When they are in a cleanser, they get rinsed down the drain before they can work. Some companies shockingly recommend leaving the cleanser on the face for several minutes so the AHAs or BHA can be absorbed into the skin, but that means the detergent cleansing agents would be left on the skin for longer than necessary, and that absolutely can cause unwanted irritation. Cleansing the face gently is imperative for everyone to have healthy skin. (Source: Skin Research and Technology, February 2005, pages 53-60 and Dermatology, March 1997, pages 258-262)
pH Sensitive AHA and BHA
AHAs work best at concentrations of 5% to 10% with a pH of 3 to 4, and their effectiveness diminishes as you go above a pH of 4.5. BHA works best at concentrations of between 1% and 2%, and at an optimal pH of 3, diminishing in effectiveness as you go past a pH of 4. Both AHAs and BHA lose their effectiveness as a product's pH goes up or the concentration of the ingredient goes down. (Source: Dermatologic Surgery, February 2005, pages 149-154 and Cosmetic Dermatology, October 2001, pages 15-18).
If the cosmetics industry isn't forthcoming about the necessary percentages and pH for a BHA or AHA product (and most companies aren't), how can you tell if it provides decent or effective exfoliation? Consumers can't, not unless they are shopping with pH measuring paper in hand, which is exactly how I rate exfoliants when I review products for my book, on Beautypedia.com, or for my Beauty Bulletins. As a general rule, it is best if the AHA ingredient is either second or third on the ingredient list, making it likely that the product contains a 5% or higher concentration of AHAs. For salicylic acid, because only a 2% to 0.5% concentration is required, it is fine if this ingredient is located toward the middle or end of the ingredient list.
It is interesting to note that at any pH, AHAs provide the added benefit of helping to keep water in the skin at the same time that exfoliation is taking place. This is due to the way they affect skin cells adding increased protection. AHAs can also increase the production of ceramides in the skin, which help keep it moist and healthy (Source: Dry Skin and Moisturizers Chemistry and Function, edited by Marie Loden and Howard Maibach, 2000, page 237).
While BHA penetrates deeper into the pore than AHAs, it can be less irritating than AHAs. This is due to BHA's relation to aspirin. Aspirin (acetylsalicylic acid) has anti-inflammatory properties and BHA, salicylic acid, is derived from aspirin and on the skin, retains some of its same anti-inflammatory benefits.
AHA Impostors
There are AHA sound-alikes, including sugarcane extract, mixed fruit acids, fruit extracts, milk extract, and citrus extract. You may think you've purchased a more natural AHA product when you see these less technical names, but that isn't the case. Although glycolic acid is derived from sugarcane, and lactic acid from milk, that doesn't mean sugarcane extract or milk extract are the same as glycolic or lactic acid, yet they do share these acid's water-binding properties, in much the same way as salicylic acid share's the anti-inflammatory properties of its relation, aspirin.
Unless you see glycolic, lactic, malic, tartaric, or citric acid on the ingredient list, it's all too vague and meaningless, making it impossible to determine what you are really buying. My advice is to be very suspicious of any product that claims an association with AHAs but contains a variety of sound-alike ingredients.
BHA Impostors
Products boasting that they contain a natural source of salicylic acid (BHA) usually add willow bark. Willow bark contains salicin, a substance that when taken orally is converted by the digestion process to salicylic acid. That means the process of converting willow bark to salicylic acid requires the presence of enzymes to turn the salicin into salicylic acid. The likelihood that willow bark in the tiny amount used in cosmetics can mimic the effectiveness of salicylic acid on skin is in all likelihood impossible. However, willow bark may indeed have some anti-inflammatory benefits for skin because, in this form, it appears to retain more of its aspirin-like composition.
What About Higher Concentrations of AHAs?
Removing the outer layer of skin can be taken too far, and many cosmetic dermatologists and researchers worry that the increased irritation and exfoliation caused by higher concentrations (above 10%) of AHAs may be too much for skin and the FDA agrees with this assessment. (Source:
www.fda.gov). Without more evidence showing a benefit from higher concentrations, I feel that you can achieve great results without any unwanted side effects when you stick with AHA products containing no more than 10% AHAs or BHA products with no more than 2% salicylic acid. Further, the positive results women and men perceive with higher concentrations of AHAs may come from the swelling and edema they cause. That may diminish the appearance of wrinkles and make the skin feel smoother, but it is most likely not best for the long-term health of the skin due to the increased amount of constant irritation.
Can You Exfoliate Too Often?
What about exfoliating too often? Does it hinder or harm cell production? Some of you have asked me about something known as the Hayflick Limit. The Hayflick response is a phenomenon that explains how many times skin cells will be reproduced. There seems to be a preset genetic determination of the number of times a skin cell will be regenerated. This turnover limit is only about what happens in the lower layer of skin where skin cells are produced (the basal layer). What happens on the surface in regard to exfoliation doesn't affect the number of times new skin cells are created. Exfoliation is strictly about the dead surface layer of skin and that doesn't get anywhere near the lower layers where new skin cells are being reproduced. Removing top layers of skin doesn't cause new skin cells to be formed; the two functions are not related. So you don't need to worry about damaging new skin cells by using topical exfoliants. You do want to be careful to avoid exfoliants that are too strong or too abrasive because of the irritation and inflammation such products cause; this can harm skin more than help it, but that still doesn't affect cell regeneration or speed up the Hayflick Limit.
You may have heard or read that some cosmetic companies are proclaiming people should stop exfoliating skin. The reasoning is that by doing so you hold on to your epidermal (surface) cells longer, which creates a more youthful look. My response to any company recommending this course of action is that they don't know what they are talking about. There is no reason to preserve our epidermal cells (the outer layers of skin), they die and shed normally! Routine exfoliation just helps them do it in a healthier, more normal manner. What they are confusing is the notion of wanting to preserve the basal layer of skin where skin cells are regenerated, but that is a genetic trigger and not something related in any way to how the surface of skin functions. If there is research showing that exfoliation changes cell regeneration I have never seen it, but I have seen lots of research showing that exfoliation is incredibly beneficial for skin. There is even research showing glycolic acid can reduce skin cancer occurrences, which is astounding.
For the health and appearance of your skin exfoliation is a key component. It is necessary for most skin types and is as basic as a gentle cleanser, sunscreen, and the need for skin to get topically applied antioxidants and cell communicating ingredients!
(Other sources for the information above: International Journal of Cosmetic Science, June 2008, pages 175-182; Journal of Cosmetic Dermatology, September 2006, pages 246-253; Phytotherapy Research, November 2006, pages 921-934; Aesthetic and Plastic Surgery, May-June 2006, pages 356-362; Journal of Dermatology, January 2006, pages:16-22; Cosmetic Science, September-October 2002, pages 269-282; Molecular Carcinogenesis, July 2001, pages:152-160; and British Journal of Dermatology, February 2001, pages 267-273.)
Polyhydroxy Acids
The search for an effective form of AHA or an extra ingredient that can enhance performance and reduce irritation has been a popular topic of discussion among cosmetics formulators. Gluconolactone is a type of polyhydroxy acid that NeoStrata (the company that developed and patented this ingredient) believes serves both ends: It is supposed to be just as effective as AHAs but also less irritating.
Gluconolactone (PHA) is similar to AHAs. The significant difference between the two is that gluconolactone has a larger molecular structure, which limits its penetration into the skin, resulting in a reduction of irritating side effects in some skin types. So is gluconolactone better for your skin than AHAs? Research indicates that AHA and PHA perform identically with AHA having a slight edge for improving the appearance of skin and PHA having less risk of irritation (Source: Cutis, February 2003, (2 Supplemental), pages14-17).
Retinoids (Retinol, Retin-A, Differin, and Tazorac)
Let me make it perfectly clear that retinoids are not exfoliants, though many people think that's what they do. Retinoids are a general term referring to a vast range of ingredients derived from vitamin A (retinol is the technical name for vitamin A). Retinol is a cosmetic ingredient while other retinoids such as tretinoin or adapalene are prescription-only topical ingredients. Prescription-only, topically applied retinoids are significant for skin because they can positively affect the way cells are formed deep in the dermis.
If you have sun-damaged, dry, wrinkled, or acne-prone skin, you should become familiar with the names Retin-A, Renova, Differin, Avita, and Tazorac, which all contain different forms of retinoids. The active ingredient in Retin-A, Avita, and Renova is tretinoin, Differin uses adapalene, and Tazorac uses tazorotene. In fact, both Renova and Tazorac have been approved by the FDA for the treatment of wrinkles (Sources: Dermatologic Surgery, June 2004, pages 864-866; Archives of Dermatology, November 2002, pages 1486-1493; Clinical and Experimental Dermatology, October 2001, pages 613-618; and www.fda.gov ).
Exfoliants such as AHAs and BHA primarily affect the top layers of skin improving its appearance, integrity, and protection potential. They also help improve the function of the pore. In contrast, retinoids affect the lower layers of skin (dermis), where new skin cells are produced. Retinoids actually communicate with a skin cell as it is being formed, telling it to develop normally instead of developing as a sun-damaged or genetically malformed skin cell.
Why the confusion about the effect retinoids can have on the skin? Primarily it's due to the fact that products containing retinoids can cause irritation and inflammation, resulting in the skin becoming flaky and dry. This flaking and dryness is not exfoliation, nor is it a desirable or advantageous result. If retinoids cause your skin to be consistently dry and flaky, it is a problem and you should probably avoid products that contain it or reduce how often you use them.
Despite the valuable effect tretinoin or adapalene can have for skin, don't expect them to "erase" wrinkles because while the improvement is impressive it is not dramatic. However, if skin cells can be produced with a healthier form and shape, the skin's surface will have a smoother appearance, skin cells will do their job of turning over in a more normal fashion, the protective outer layer of skin will remain intact, enhancing the skin's healing response, and on and on. In essence, the skin will behave and look the way it did (to some extent) before it was damaged by the sun.
Regardless of these positive effects, retinoids will be useless, and the skin will be prone to more damage, if you do not wear a sunscreen as well. Not a wrinkle cream in the world, even one approved by the FDA, can have positive results if you don't use an effective sunscreen; without that, you are just adding to damage you already have accumulated.
What retinoids, AHA, and BHA products have in common is that once you stop using them, your skin will revert to the way it was before. These products will not produce permanent change. The smooth exterior lasts only as long as you use them. But used together long-term, they are a formidable weapon in the battle against wrinkles and blemishes.
What About Sun Damage?
The FDA feels and some research has shown that there is a risk of UVB sun sensitivity (sunburn) following the use of AHAs. That makes sense, given that AHAs work to remove sun-damaged skin, and that leaves the skin somewhat more vulnerable to the effects of UV rays. The thickened, damaged layer of dead built up skin caused by years of unprotected sun exposure does offer a small amount of protection from the sun. When you remove that damaged layer with exfoliants, the skin reverts back to how it behaved when it was younger without the impact of built up sun damage. That is what makes skin look better but also creates a renewed risk of sensitivity to the sun. Of course this sensitivity is easily preventable with the diligent use of lower concentrations of AHA (10% or less) and a sunscreen. Research does show AHAs to be safe in 4% to 8% concentrations with a pH of 3 to 4 (Source: Journal of Cosmetic Science, November/December 2000, pages 343-349). As I mentioned above there is research showing that glycolic acid and salicylic acid actually protects the skin from sun damage. Nonetheless, regardless of the research about AHAs and BHA it is imperative that you wear a sunscreen every day, one with an SPF of at least 15 that includes avobenzone (trade name Parsol 1789, chemical name butyl methoxydibenzoylmethane), titanium dioxide, zinc oxide, or Mexoryl SX (ecamsule) to protect skin from UVA damage. Sun damage is a problem every day of the year regardless of any other aspect of your skin care routine.
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