4 Not-So-Natural Ingredients Hiding in Skincare Products

By Raja Sivamani, MD, and Ashley Dumont

The Rise and Regulation of Natural Skincare Products

As consumers become more and more aware of harmful ingredients in their skincare products, many are turning to “healthier” and “safer” options that include labels such as “natural” and “organic.”1 The term “organic” used in skincare products is not defined by the FDA, and the term “natural” has no legal definition.1,2 Without clear definitions and guidelines, consumers are increasingly swayed by savvy marketing techniques and may think that natural products do not have side effects. While natural products have seen an impressive growth and our knowledge of the science of ingredients has expanded, your patients should be aware that “natural” products may still have hidden ingredients that are not so “natural” and may cause irritation. Below, are four not-so-natural ingredients hiding in natural skincare products.


Preservatives that are used to increase the shelf life of skincare products and inhibit microbial growth are often used in products that are marketed as “natural,” “organic,” “gentle,” and “hypoallergenic.”3-6 The use of preservatives in skincare products has been linked to allergic contact dermatitis.8,9 The following are 4 common preservatives found in natural skincare products.3,7,8

  • Methylisothiazolinone
  • Phenoxyethanol
  • Sodium benzoate
  • Potassium sorbate

The following products may contain preservatives:3

  • Facial/ body wipes
  • Soaps
  • Moisturizers
  • Sunscreens
  • Bubble baths
  • Shaving products
  • Antiperspirants
  • Shampoos/ conditioners


Fragrances are used in skincare products to enhance their scent.10 The term “fragrance” on a label is an unregulated, catch-all term that includes thousands of synthetic fragrances that are not required to be on the product label.10,11 Products that are labeled as “unscented” may still contain fragrances to hide the scent of other ingredients used in the product.10 Products that are labeled “fragrance-free” may contain fragrances that are used for a different intention (such as a preservative) and may be allowed in as an ingredient.

Common synthetic fragrances that may be found in natural skincare products:12-14

  • Phenoxyethanol
  • Benzyl salicylate
  • Isothiazolinone
  • Benzyl alcohol
  • Synthetic nitro musks

Common plant-derived fragrances that may be found in natural skincare products:15

  • Geraninol
  • Citronellol
  • Citral
  • Farnesol
  • Comuarin
  • Eugenol
  • Cinnamyl alcohol
  • Isoeugenol
  • Cinnamal
  • Limonene

Topical exposure to fragrances can lead to contact dermatitis.16 Even plant-derived fragrances used topically can contribute to allergic contact dermatitis and photosensitivity.17 In a study looking at sensitizing fragrances, limonene was the most commonly reported fragrance allergen in causing allergic contact dermatitis.18

The following products may contain fragrances:10,19

  • Perfume/ cologne
  • Shampoo/ conditioner
  • Shaving products
  • Facial cleansers
  • Soaps
  • Moisturizers
  • Antiperspirants
  • Sunscreens
  • Facial/body wipes
  • Cosmetics

Coloring dyes

Coloring dyes are used in hair dyes, coloring shampoos, and eyelash dyes to alter one’s natural hair color. Coloring dyes are also used in henna inks to create temporary tattoos on the skin.20,21 Those most exposed to harmful coloring dyes are typically hair stylists, beauticians, and henna artists.20

Common coloring dyes:20,22

  • Paraphenylenediamine
  • Eosin
  • Rose Bengal
  • Methelyne blue
  • Anthraquinone

Coloring dyes can become more irritating when exposed to the sun and cause toxic and allergic effects.20 Exposure to coloring dyes can cause allergic contact dermatitis, and if used on the eyelashes can cause irritating reactions and potentially damage the cornea.21

The following products may contain coloring dyes:20,21

  • Hair dyes
  • Coloring shampoos/ conditioners
  • Henna ink
  • Eyelash dyes
  • Color cosmetics

Propylene glycol

Propylene glycol is a synthetic, organic compound that is used in foods, skincare products, medications, and plastics.23 In natural skincare products, propylene glycol is often listed under the term “fragrance” and is used as a humectant, preservative, and to increase absorption and promote the spread of the product into and onto the skin.23,24

Propylene glycol was named the American Contact Dermatitis Society’s Allergen of the Year for 2018.23 In 2007, propylene glycol was considered to be the sixth most common skin allergen.24 Systemic reactions, along with contact and irritant reactions, have been documented with patch tests of propylene glycol.23-26 Even 2% of propylene glycol administered to the skin can cause contact dermatitis.27 The topical use of propylene glycol has been shown to increase the penetration of other topical medications, such as cortisone, that can lead to an increase systemic level of cortisol, which can be dangerous, especially in children.28,29

The following products may contain propylene glycol:30

  • Moisturizers
  • Antiperspirants
  • Personal lubricants

Summary and Practical Tips

The growth in research and the use of “natural products” is exciting. As a healthcare practitioner, it is important to teach your patients that “natural” does not automatically mean safer and it is still important to read ingredient labels. More importantly, any new product has the potential to cause an allergy and should be tested in a small area prior to use. A good area to test the product is on the inside of the arm so that if the skin reacts, it will be in a hidden location.

There are several resources to help the general public learn more about ingredients including the Environmental Working Group and the Cosmetic Ingredient Guide from the European Commission.

About the Authors

Raja Sivamani, MD, is a board-certified dermatologist and Ayurvedic practitioner who serves as the lead scientific advisor and editor for Dermveda and LearnSkin. He is an associate professor of clinical dermatology at the University of California, Davis and serves as the director of clinical research and the Clinical Trials Unit. He is also an adjunct assistant professor in the Department of Biological Sciences at the California State University, Sacramento. Sivamani has published over 100 peer-reviewed research manuscripts, 10 textbook chapters, and a textbook titled Cosmeceuticals and Active Cosmetics, 3rd Edition. 

Ashley Dumont is a third-year naturopathic medical student at National University of Natural Medicine. She graduated from the University of New England in 2016 with a Bachelors of Science in Medical Biology and a minor in Sociology. With a deep-rooted passion for dermatology, she believes in taking an evidence-based, holistic approach to skin health including mindfulness, a diet rich in whole foods, movement, proper digestion, and prevention. Ashley recognizes the importance of overall health, and its impact in developing radiant and healthy skin.


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