This is the best resource to learn all about skincare ingredients! It is written by skin care ingredient expert Dr. Leslie Baumann MD. This cosmeceutical dictionary contains information about skincare ingredients from my best selling skin care book and dermatology textbooks and my monthly skin care ingredient review column in Dermatology News called “Cosmeceutical Critique.” I have been writing about skin care ingredients for over 25 years.

The ingredient information in this skin care ingredient dictionary is based on evidence - based research.  If you do not know exactly what that mans- please click this link and learn how to tell if a research study is good.

This ingredient glossary is constantly being updated to stay as current as possible.

You can find categories of skin care ingredients based on their skin benefits and a list of skin care ingredients by INCI name. 

Click on the ingredient to find more detailed information and to find skin care products that contain that ingredient.  All benefits and risks of the skin care ingredients can be found in the individual skin care ingredient blogs.

You can learn more about clean ingredients and the clean beauty standards here.

There are several ways to become an expert on skin care ingredients:

1. Read my bestselling skin care books
2. Visit our skin care ingredient library
3. Click on the categories below 
4. See the list of skincare ingredients and click for detailed information about each ingredient.
5. Go to our You Tube channel where I interview cosmetic chemists.

The easiest and best way to learn about skin care products is to divide ingredients into categories based skin benefits.

Many antiaging ingredients target the causes of skin aging like cellular senescence.

Anti-aging ingredients work by:

• Stimulating the production of important skin components, such as collagen and hyaluronic acid.
• Helping cells communicate better with each other. 
• Stimulating Autophagy
• Protecting Skin from pollution
• Neutralizing free radicals

The most commonly used antiaging ingredients include ascorbic acid, retinoids, defensins, hyaluronic acid, heparan sulfate, peptides and growth factors.

Click on the ingredient name or category to learn more about antiaging cosmeceutical ingredients in skincare products.

Exosomes are the most exciting and newest cutting edge ingredients to treat wrinkles. Click the link to learn more about the different types of exosomes.  You can also learn more by watching our YouTube video about a new platelet derived exosome product.

There are many types of growth factor skin care ingredients.  The benefits and side effects depend upon which type of growth factor and if they come from humans or plants. Clink the link to learn more and get a list of growth factors in skin care.

There are many types of antiaging peptides. Peptides are made up of amino acids. Click here for a list and to see which are best.

All retinoids are antiaging.  How strong they are depends upon their strength. They target many different antiaging pathways and have many research studies to show they are the best antiaging ingredients in skin care.

Antioxidants neutralize harmful free radicals. They can be used to prevent aging, calm inflammation, and prevent uneven skin pigmentation. Antioxidants are naturally found in many plants. Examples include Vitamin C, Vitamin E, resveratrol, green tea and silymarin. Click here  to learn more about cosmeceutical antioxidant ingredients in skincare products.

See the section of anti-redness and anti-inflammatory ingredients under the antiaging category above or click here.

There are many different standards of clean ingredients. Our dermatologists reviewed ingredients and set our own clean beauty standard. Learn details here.

The skin’s natural exfoliation process is called desquamation. When natural desquamation is not enough, exfoliants can be used to increase exfoliation. There are two types of exfoliants: chemical and mechanical. Chemical exfoliants use a low pH or enzymes to dissolve and loosen proteins attachments between skin cells. Mechanical exfoliants use friction to rub dead skin cells off of the surface of the skin.

Chemical exfoliants such as glycolic and lactic acids have a low pH and work by loosening the “glue” attachments between skin cells. This allows dead skin cells to flake off of the skin’s surface in a process called exfoliation.

There are many ways that an ingredient can contribute to moisturizing the skin. The most common mechanisms for hydrating the skin include:

• Barrier repair ingredients - When the skin barrier becomes damaged, it has trouble holding onto water and keeping allergens and irritants out. Barrier repair moisturizers contain ceramides, fatty acids, cholesterol, or beta-sitosterol to strengthen and repair this barrier. 
• Fatty Acids - Ingredients like linoleic acid, linolenic acid, oleic acid, stearic acid, palmitic acid, lauric acid, and others have various moisturizing anti-inflammatory, and barrier repairing properties.
• Humectants - Humectants are ingredients that draw moisture towards themselves, resulting in increased moisture on applied areas. We have a full list of humectants here.
• Occlusives - Occlusive ingredients create a thick layer on the skin that water cannot get through. Thick, saturated oils and other creamy substances are the most common occlusives. Check out our detailed list of occlusive ingredients here!
• Oils - Oils are ingredients composed of various lipids and polyphenols based on which plants they come from. We have a full list of the most common oils in skin care here!

Most ingredients that act as fragrances are in the category of essential oils. For the most part, essential oils are very thin and watery oils that have to combined with thicker substances for good delivery in skin care. Some fragrant ingredients like rose oil do have some mild benefits in skin care. 

Skin lighteners, brighteners, and whiteners are a group of skincare ingredients that even skin tone. They may be called skin brighteners. They work by one or more of the following: block production of melanin, block transfer of melanosomes from the melanocyte to the keratinocyte, or increasing exfoliation.

Proteinase-activated receptor 2 (PAR-2) is located in the connection between keratinocytes and melanocytes. It functions as a doorway to allow melanin laden melanosomes to enter into the keratinocyte after being produced by melanocytes. PAR-2 blockers prevent melanin from entering keratinocytes. Examples include niacinamide and proteins found in soy.

• Aminobenzoic acid (PABA): Once common in sunscreens but now rarely used due to the potential for skin irritation and the risk of clothes staining.
• Avobenzone
• Cinoxate
• Dioxybenzone
• Ensulizole (Phenylbenzimidazole Sulfonic Acid)
• Homosalate
• Meradimate (Menthyl Anthranilate)
• Octinoxate (Octyl Methoxycinnamate)
• Octisalate (Octyl Salicylate)
• Octocrylene
• Oxybenzone
• Padimate O
• Sulisobenzone
• Trolamine Salicylate

• Zinc Oxide: Offers broad-spectrum protection, shielding the skin from both UVA and UVB rays. Zinc oxide is often favored for sensitive skin and can be found in many "baby" sunscreen formulations.

• Titanium Dioxide: While it also provides broad-spectrum protection, titanium dioxide is particularly strong in guarding against UVB rays.

Both of these ingredients work by sitting on the surface of the skin and reflecting away the UV rays, rather than absorbing them like chemical sunscreens. As such, they're often referred to as "physical blockers" or "inorganic sunscreens." Because of their mode of action and the fact that they don't penetrate the skin deeply, mineral sunscreens are generally considered safer for sensitive skin and have fewer concerns related to systemic absorption or potential hormonal disruption.

1. Baumann, L. Cosmeceuticals and Cosmetic Ingredients (McGraw Hill 2015)
2. Baumann's Cosmetic Dermatology (McGraw Hill 2022)
3. https://www.mdedge.com/dermatology/cosmeceutical-critique
4. Baumann, L. (2006). The skin type solution: a revolutionary guide to your best skin ever. Bantam.
5. Baumann, L. (2019). Cosmeceuticals and skin care in dermatology. U: Kang S, Amagai M, Bruckner AL, Enk AH, Margolis DJ, McMicheael AJ i sur., ur. Fitzpatrick’s dermatology, 9, 3803-19.
6. Baumann, L., Rodriguez, D., Taylor, S. C., & Wu, J. (2006). Natural considerations for skin of color. Cutis, 78(6 Suppl), 2-19.
7. Baumann, L. S. (2007). Less‐known botanical cosmeceuticals. Dermatologic therapy, 20(5), 330-342.
8. Baumann, L. (2018). How to use oral and topical cosmeceuticals to prevent and treat skin aging. Facial Plastic Surgery Clinics, 26(4), 407-413.
9. Grunebaum, L. D., & Baumann, L. S. (2014). Nonprescription topical treatments for skin rejuvenation. Facial plastic surgery, 30(01), 003-011.
10. Monteiro, E. D. O., & Baumann, L. S. (2006). The science of cosmeceuticals. Expert Review of Dermatology, 1(3), 379-389.
11. Baumann, L. (2016). Cosmeceuticals in skin of color. , 35, 4, 35(4), 233-237.
12. Baumann L. Ch 14. Scientific Approach to Cosmeceuticals in Warren, R. J. (2021). The Art of Aesthetic Surgery: Principles and Techniques.