Women in Cosmetology – Doctor Leslie Baumann

Dermatologist, Researcher and Author

CEO, Skin Type Solutions Franchise Systems Founder

Division of Cosmetic Dermatology, University of Miami, Florida

With a vibrant energy, a tireless drive and passion for skincare science, Doctor Leslie Baumann tells us about the concept of “skincare ingredients layering” and the importance of using the right regimen of products


About your career and the people who inspired you: When I was growing up, I was (and still am) an avid reader.  I was always fascinated with reading biographies, particularly biographies about business CEOs such as Estee Lauder, Elizabeth Arden, Helena Rubinstein, Charles Revson and Mary Kay. For decades I have followed the various skincare companies and skincare trends.  I knew very early on that I wanted to become a doctor, but it never occurred to me that these two interests would merge. At the end of my Dermatology Residency at The University of Miami in 1996,the chairman William Eaglstein was smart enough to recognize that my passion for skincare would be an asset to help develop the first academic research center in the USA dedicated to the research of skincare technologies and cosmetic procedures.  I agreed to develop a Cosmetic Dermatology Division within the Department of Dermatology in exchange for being named the Director of the Division of Cosmetic dermatology. I remember that moment like it was yesterday when Dr. Eaglstein agreed and said, “You realize that you are really just the Director of yourself.” When I left the University of Miami in 2009, I had built the division to have a budget of $3.5 million a year and had 30 employees. My research team performed the research trails on almost all the cosmetic injectable products including Botox for many indications, Dysport, Juvederm, Restylane Silk, Voluma and Sculptra in addition to many topical cosmeceutical and prescription medication trials such as TriLuma, Rhofade and Tazorac.  My passion for skincare science and the history of the personal care product industry combined with smart mentors, attention to detail and the strong belief that I can make a difference in the skin health of many people by teaching them what skincare technologies to use have shaped my career and led me to advance research in the field of Cosmetic Dermatology.



What is the concept of skincare product “layering”? The order in which you apply skincare ingredients onto the skin is critical. The fascinating chemical reactions between ingredients is not being given enough attention. Ingredients interact with each other and change each other. They are sensitive to the environment they are in:  the temperature, the pH, humidity and the microbiome all play a role in the activity of skincare products placed on the skin. The chemistry of ingredients and how they interact is very well understood by personal care product formulators.  They are like chefs who use the chemistry of the ingredients and how they react with each other to affect the flavor of the food they cook.  The best skincare product formulators understand this concept and they put a lot of thought into the order that they put the ingredients in the formula, the temperature, and how fast they stir the formula. For example, ceramides are often placed in moisturizers along with fatty acids and cholesterol because these are well known barrier repair ingredients. The ratio of ceramides, fatty acids and cholesterol must be 1:1:1 for the product to be effective at repairing the barrier 1. Using a different ratio has been shown to disrupt the barrier.  In addition to putting the proper ratio of ceramides in the formulation, the order of when they are added to the mix matters. Ceramides are a waxy substance that needs heat to liquify and form the proper mixture with the other ingredients.  However, heat can inactivate ingredients like Vitamin C and Vitamin E.  This is the art of skincare formulation.  The same chemistry considerations should be considered when designing a skincare regimen. If a low pH skincare product (like a glycolic acid cleanser) is used on the skin, this is going to affect what is going to happen with the next product that is placed on the skin. This is one of many chemistry reactions that should be considered when designing the order of skincare product application when designing a skincare regimen.

Do Consumer care about this idea of Skincare Layering? Consumers care a lot about this. At least once a month I get a question on my Skin Type Solutions Facebook Page about skincare product layering. For example, I am often asked: “Can I layer this vitamin C on top of my green tea product…or when should I apply my sunscreen— before or after my moisturizer? The savvy consumer asks about the “troublesome” ingredients– the ones that do not “play well in the sandbox” with the other ingredients such as benzoyl peroxide, retinoids, hydroxyacids, hydroquinone, Vitamin C and peptides. These are all ingredients that are somewhat difficult to formulate because they readily react with another ingredients. Their combined use should be carefully orchestrated through the recommendation of the right regimen of products.

What about the role of Cleansers in skincare layering?  Cleansers matter more than most people realize. The cleanser plays an important because it affects the pH of the skin, loosens attachments between cells, desquamates layers from the stratum corneum, and affects the penetration of the next product that is placed on the skin. The choice of a cleanser is critical for efficacious skincare regimens. Cleansers should be chosen based on the patient’s Baumann Skin Type® 2 and by what products will follow them in the regimen.

What happens if you do not layer the products properly? Improper layering of skincare products will decrease efficacy and increase the risk of side effects. Acne skincare regimens are a good example. When a patient is on retinoic acid, benzoyl peroxide and/ or salicylic acid for acne, these formulas dry out and irritate the skin. Very often, patients end up not tolerating their acne medication and patient compliance is a big problem in the treatment of acne.

Does layering skincare products affect patient compliance?

Compliance with any skincare regimen is a huge problem for dermatologists.  Studies have shown that 95 % of people under-dose and 1 out of every 3 prescriptions 3 is not even filled. If patients buy the acne medication, they often have side effects that cause them to stop using the medications, or they under dose. Prescribing the proper cleanser and moisturizer to accompany the acne medications will decrease side effects and increase compliance. Getting your patients to use products the right way is critical. Educating them so they know what to use, how often to use, how much to use and when to stop medications will help increase compliance.  Many studies show that the best way to increase compliance is to give the patient written instructions. They should be given a written regimen with Step 1, Step 2, Step 3 etc. so they understand when to apply each product.

Are there any scientific evidence behind the importance of “layering ingredients?

Dr Sheldon Pinnell did a lot of great studies on Vitamin C and showed that at pH of 2-2.5 increases the absorption of Vitamin C 4. This means that if you wash your skin with something like a glycolic acid cleanser (usually a pH of 2.5-3.5) it will lower the pH of your skin and help promote absorption of Vitamin C. On the contrary, If you wash your skin with an alkaline soap (often a pH of 9 or more), you are going to raise the pH of your skin. Even a Vitamin C serum that is a pH of 2.0 will have less absorption when placed on skin of a higher pH. Other ingredients that affect penetration include oleic acid, hyaluronic acid, stearic and other lipids.

Would it be better to use products all from one brand to know that the products layer well together? In many cases the companies do not research the products as a complete regimen, but rather as an independent product.  For this reason, we often do not know if the product will be efficacious when combined with other products.  I believe that dermatologists should choose the best “hero” products form the various brands and layer them in the proper way to increase efficacy.  I prefer products from various brands because each company has a core competency.  For my patients I like to choose the best technologies form each brand and combine them.  Not one brand can have the best of every type of product.  Combining these in an efficacious layering pattern will give the patient the best of all the brands. I combine products from various brands and match them to the patient’s Baumann Skin Type.  I then test the outcomes of these combinations independently from the brands.  I have found that I have better patient compliance and improved outcomes using this technique. Because it is a lot to think about, I developed software that does this automatically for me.  That way I know that my staff can provide the same correct skin care regimen advice as I can.

How can patient know that they are applying their skincare products in the right order?

There is no way patients can know how to best layer products on their skin.  In fact, unless a dermatologist is as passionate about skincare as I am, they also may not be able to properly design regimens.  For this reason, I started a company called Skin type Solutions franchise systems which allows doctors to sue the software that I developed.  They choose hero products from 40+ brands. They can even do private label though one of the companies if they prefer. The key is that the product must meet certain criteria so that when they are layered with other products they increase efficacy and decrease side effects. It has taken me about a decade to research and patent this but now over 100 doctors in the USA are using my Skin Type Solutions Software to diagnose the patient’s Baumann Skin type and prescribe a matching skincare regimen. It has made my clinic so much more efficient and my patients love learning what their Baumann Skin Type and getting a corresponding skin care regimen with clearly marked steps.  I now have a mobile app that patients can use to get their regimen steps and instructions.

How could Industry further advance this concept of “Skincare Layering”? At first, I would like to see the expert personal care product formulators help educate Dermatologists more about the issues they face making the skincare products. There are so many poorly made products out there and it is hard to know who the best skincare formulators are. Another way industry can help is by testing skincare products against various skin types. The efficacy of products varies by what the skin type for the patient is. Skincare companies could also help buy giving us guidance about what types of products should be used before and after their product to increase efficacy.



The most recent exciting innovations in Skincare: The 2 things that have recently caught my interest are Heparan Sulfate and Defensin. Heparan Sulfate 5 is exciting because it does things very differently than current anti-aging ingredients. It is a glycosaminoglycan, a sugar that we naturally have in our skin and it is known to protect growth factors, surround them and carry them to the receptors on the skin cells.  This helps old cells hear the growth factor signals better. Whether the signal is a Vitamin C, a Retinoid or a Growth Factor signal, the Heparan Sulfate can enhance keratinocyte response. The second one is Defensin 6. It is a peptide that is stabilized in a liposome so that it does not interfere with other ingredients. (Peptides are well known to be troublesome ingredients.) The liposome encapsulated defensin goes down the hair follicle and activates the LCR6+ stem cells that are involved in reepithelization after wounding.  Stem cells in cosmeceuticals are not efficacious for many reasons.  Defensin turns on native stem cells to repopulate the epidermis with younger cells.

How important is Skin Health for you and how would you define it?  Skin Health is the absence of the 4 main barriers to healthy skin which are: 1.  Dehydration 2. Inflammation 3. Disordered pigmentation and 4. Inactive fibroblast and keratinocytes. The definition of skin health is the same across all skin ethnicities.  A validated questionnaire determines which of these barrier to skin health are present and assigns a Baumann Skin type. The 3-5 minute questionnaire has been validated in many ethnicities, ages, both genders and many geographic locations 7,8.  Skin Type Solutions Franchise Systems (STSFranchise.com) allows dermatologists in the US to license the use of the Skin Type Solutions Skin Typing System to generate efficacious skin care regimens designed to improve skin health.

What does the future of skincare look like?

Along the years, I have noticed that my patients seem to be getting most of their skincare information off of the internet. The problem is that the new evidence-based science in Skincare is complicated to a non-dermatologist to understand.  Our 14+ years of science training allows us to understand the subtleties of these advances that the average layperson cannot understand. I believe that patients need guidance to navigate these marketing claims and I encourage dermatologists to discuss skincare regimens with their patients and give them written clear instructions. In addition, dermatologists need to reach out help educate consumers on what is true about skincare.  For example, I saw recent statistics 9  that the average American woman spends $8 a day on her face – and none of these products is a sunscreen! We can work together to change this.



  1. Mao-Qiang, Man, et al. “Optimization of Physiological Lipid Mixtures for Barrier Repair” J Invest Dermatol5 (1996): 1096-1101.
  2. Baumann, Leslie S. “The Baumann Skin Typing System” in Farage MA, et al. Textbook of Aging Skin. Springer-Verlag Berlin Heidelberg (2017): 1579-1594.
  3. Storm, A., Andersen, S. E., Benfeldt, E., & Serup, J. (2008). One in 3 prescriptions are never redeemed: primary nonadherence in an outpatient clinic. Journal of the american academy of dermatology59(1), 27-33.
  4. Pinnell Sr, Yang H, Omar M, Monteiro-Riviere N, DeBuys HV, Walker LC, Wang Y, Levenine M. Topical L-ascorbic acid percutaneous absorption studies. Dermatol Surg. 2001 Feb; 27(2):137-42
  5. Taub et al. Multi-center, Double-blind, vehicle-controlled clinical trial of an alpha and beta defensin-containing anti-aging skin care regimen with clinical, histopathologic, immunohistochemincal, photographic, and ultrasound evaluation. JDD in press
  6. Leslie Baumann. Heparan Sulfate. Cosmeceutical critique. Dermatology News January 2017
  7. Baumann, Leslie. “Validation of a Questionnaire to Diagnose the Baumann Skin Type in All Ethnicities and in Various Geographic Locations” Journal of Cosmetics, Dermatological Sciences and Applications 6 (2016): 34-40.
  8. Baumann, Leslie S., et al. “A Validated Questionnaire for Quantifying Skin Oiliness” Journal of Cosmetics, Dermatological Sciences and Applications 4 (2014): 78-84.
  9. https://www.huffingtonpost.com/entry/how-much-is-your-face-worth-american-women-average_us_58befa65e4b06660f479e594