Weekly Newsletter: Clean Beauty, Part I
Macrene Alexiades, MD PhD
Associate Clinical Professor, Yale University School of Medicine
Director and Founder, Dermatology and Laser Surgery Center of New York
CEO and Founder, MACRENE actives
Defining Clean Beauty
Consumers have become increasingly concerned about toxic exposure from skincare, environmental effects of manufacturing practices and packaging, and ethical concerns surrounding animal or human-derived ingredients. There is evidence indicating that topical agents may result in local and systemic reactions and carcinogenicity from toxic exposures, that certain ingredients are manufactured with inhumane practices, that plastic packaging may leach harmful chemicals into your skin and the environment, and that animal or human byproducts may be hidden in your skincare. As a result, there is a growing demand for greater transparency of ingredient usage and manufacturing practices and for the elimination of potentially harmful ingredients or packaging. This article defines the categories of skincare ingredients, manufacturing, and packaging that are demonstrated to be harmful to the health of humans, animals and/or the environment or that raise ethical concerns.
The definition of clean beauty de facto commands the designation of unclean ingredients or packaging components with a rationale for their exclusion. Skincare ingredients, manufacturing practices or packaging components may be classified by chemical class, adverse effects, environmental harm and ethical concerns. The banning of unclean ingredients may be due to direct or indirect toxicity, such as carcinogenicity, sensitization, such as allergic contact dermatitis, environmental effects, such as marine ecosystem disruption, or ethical concerns, such as manufacture by underage children or use of animal or human-derived byproducts.
Unclean Ingredient Classes
The first focus of this article to the classification of unclean ingredients to be eliminated from skincare. While they may and should be categorized by their chemical name or class, it is far more informative to group according to their adverse effects first on human health, though subsequent parts of this work will focus on adverse environmental effects, ethical concerns, and the use of animal and human byproducts.
I. Adverse Effects on Human Health
Cancer-causing ingredients, known as carcinogens, may interrupt normal cell function in a variety of ways. The one aspect all cancer cells have in common is uncontrolled reproduction. The unbridled cell cycle results in the proliferation of cancer cells that accumulate in tumor formation, and with additional changes to the genetic material of cancer cells, they may acquire the ability to metastasize or spread.
The mechanism of action of carcinogens varies widely from direct mutagens that enter the nucleus of the cell and alter the DNA resulting in loss of normal cell function and controls to action on the receptors of cells causing downstream effects on hormones and cellular proliferation. One example of the latter are the so-called hormone disruptors; these are ingredients that either mimic hormones by binding to hormone receptors or that indirectly result in the upregulation of hormone secretion, ultimately causing increased cancer risk (Smith et al 2015).
Smith MT, Guyton KZ, Gibbons CF, et al. Key Characteristics of Carcinogens as a Basis for Organizing Data on Mechanisms of Carcinogenesis. Environ Health Perspect. 2016;124(6):713‐721. doi:10.1289/ehp.1509912
1. Hormone disruptors
a. Synthetic phenolic antioxidants (SPAs)
Butylated Hydroxyanisole (BHA) and Butylated Hydroxytoluene (BHT)
BHA and BHT are SPA preservatives employed in skincare which have been implicated as carcinogens in skin (Sato et al 1987). BHA has been shown to increase estrogen secretion (Yang et al 2018).
Sato H, Takahashi M, Furukawa F, et al. Initiating potential of 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (AF-2), butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and 3,3',4',5,7-pentahydroxyflavone (quercetin) in two-stage mouse skin carcinogenesis. Cancer Lett. 1987;38(1-2):49‐56. doi:10.1016/0304-3835(87)90199-6
Xiaoxi Yang, Wenting Song, Na Liu, Zhendong Sun, Ruirui Liu, Qian S. Liu, Qunfang Zhou, and Guibin Jiang. Synthetic Phenolic Antioxidants Cause Perturbation in Steroidogenesis in Vitro and in Vivo. Environmental Science & Technology 2018 52 (2), 850-858 DOI: 10.1021/acs.est.7b05057
Methylparaben, Ethylparaben, Propylparaben, Isopropylparaben, Butylparaben, Isobutylparaben, and Benzylparaben
The parabens are used as preservatives in cosmetic products. The estrogenic effects of parabens have been demonstrated and the association with breast, uterine and prostate cancer reviewed by the author (Alexiades 2008; Karpuzoglue et al 2013).
Alexiades-Armenakas M. Parabens toxicity to skin and other organs. J Drugs Dermatol. 2008;7(1):77‐78.
Karpuzoglu E, Holladay SD, Gogal RM Jr. Parabens: potential impact of low-affinity estrogen receptor binding chemicals on human health. J Toxicol Environ Health B Crit Rev. 2013;16(5):321‐335. doi:10.1080/10937404.2013.809252
Phthalates are used to make plastics flexible and are well established hormone disruptors. While they may appear on product ingredient labels, they may also be hidden under the term “fragrance.” They have been demonstrated to have adverse effects on male and female reproduction, breast development and cancer, prostate cancer, neuroendocrinology, thyroid, metabolism and obesity, and cardiovascular endocrinology (Diamanti-Kandarakis et al 2009).
Diamanti-Kandarakis E, Bourguignon JP, Giudice LC, et al. Endocrine-disrupting chemicals: an Endocrine Society scientific statement. Endocr Rev. 2009;30(4):293‐342. doi:10.1210/er.2009-0002
d. Chemical Sunscreens
Benzophenones (Oxybenzone, Sulizobenzone), Cinnamates (Octinoxate, Octocrylene), Camphors
Chemical sunscreens exert hormone disrupting effects on estrogens, androgens, thyroid hormones and progesterone (Wang et al 2016). Adverse effects on neurohormones have been extensively documented (Ruszkiewicz et al 2017).
Wang J, Pan L, Wu S, et al. Recent Advances on Endocrine Disrupting Effects of UV Filters. Int J Environ Res Public Health. 2016;13(8):782. Published 2016 Aug 3. doi:10.3390/ijerph13080782
Ruszkiewicz JA, Pinkas A, Ferrer B, Peres TV, Tsatsakis A, Aschner M. Neurotoxic effect of active ingredients in sunscreen products, a contemporary review. Toxicol Rep. 2017;4:245‐259. Published 2017 May 27. doi:10.1016/j.toxrep.2017.05.006
Bisphenols were banned as ingredients in cosmetic formulations in 2006, but are used as a coating material in plastic packaging, such as plastic bottles, tubes and aerosols, where it serves as an anti-corrosive. BPs have been shown to leach into the plastic container’s contents resulting in widespread human exposure (Gao et al 2015). The estrogen-mimicking effects of BPs have been established to lead to cancer of the breast, ovary and prostate (Gao et al 2015). For this reason, plastic containers may release these carcinogenic ingredients into skincare. Many plastic manufacturers have skirted the toxicity of bisphenol A (BPA) and labeling their plastic “BPA-free” by substituting with alternate bisphenols such as bisphenol S (BPS) which are likely just as toxic (Bilbrey 2014).
Gao H, Yang BJ, Li N, et al. Bisphenol A and hormone-associated cancers: current progress and perspectives. Medicine (Baltimore). 2015;94(1):e211. doi:10.1097/MD.0000000000000211
Bilbrey J. BPA-Free Plastic Containers May Be Just as Hazardous. Scientific American, August 11, 2014. https://www.scientificamerican.com/article/bpa-free-plastic-containers-may-be-just-as-hazardous/ accessed June 12, 2020.
Triclosan is a broad-spectrum antimicrobial frequently used in personal care products that has been shown in multiple studies to disrupt hormonal systems (Weatherly et al 2017). While banned from soap products in 2016, triclosan continues to be used in hand sanitizer, toothpaste, and mouthwash.
Weatherly LM, Gosse JA. Triclosan exposure, transformation, and human health effects. J Toxicol Environ Health B Crit Rev. 2017;20(8):447‐469. doi:10.1080/10937404.2017.1399306
In order to eliminate the hormone disruptor carcinogens aforementioned and to qualify as Clean Beauty, the following first three criteria as defined in Part I must be met by the product:
not contain the carcinogenic ingredients listed above on their ingredient listing
not be packaged in plastic, but rather in glass containers
Summary of Part I
In this first part of my series on Defining Clean Beauty, I have defined the criteria for clean beauty and for unclean ingredients and practices. This first part commenced with a focus on cosmetic ingredients that are carcinogens. The first sub-category discussed are the hormone disruptors, whose mechanisms of action have been defined and the research demonstrating their link to cancers cited. In order to qualify as clean beauty, the product must not contain the carcinogenic ingredients on their ingredient list; must be fragrance-free; and must not be packaged in plastic, but rather in glass. In the absence of these three criteria, the product may not be considered clean beauty. In the next part, we will cover the next cancer-causing ingredient classes, followed by allergenic and sensitizing ingredients that cause dermatitis, and ingredients associated with other forms of toxicity.