Skin hyperpigmentation – whether it is caused by postinflammatory hyperpigmentation from acne or trauma to the skin, melasma, autoimmune disorders, or disorders of pigmentation – is a condition where treatment is commonly sought after in dermatology offices. Topical products used to fade hyperpigmented areas of the skin have long been used around the world, and because of safety concerns, regulations aimed at reducing potential harm or adverse effects caused by certain ingredients in these products are increasing in different countries.
For example, while extremely effective at treating most forms of hyperpigmentation, hydroquinone has been definitively linked to ochronosis, kojic acid has been linked to contact dermatitis in humans, and acid peels and retinoids are associated with irritant dermatitis, disruption of the skin barrier, and photosensitivity. In animal studies, licorice root extract has been linked to endocrine and other organ system irregularities.
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Kojic acid was banned in Japan in 2003, and subsequently in South Korea and Switzerland because of concerns over animal studies indicating that its fungal metabolite might be carcinogenic (. Hydroquinone is classified as a drug and has been banned for use in cosmetic products in Japan, the European Union, Australia, and several African nations since at least 2006 because of concerns over adrenal gland dysregulation and high levels of mercury in hydroquinone products in those countries. In Africa specifically, South Africa banned all but 2% hydroquinone in 1983, the Ivory Coast banned all skin whitening creams in 2015, and in 2016, Ghana initiated a ban on certain skin products containing hydroquinone.
The United States followed suit in February 2020 with the Food and Drug Administration introducing a ban on all OTC hydroquinone-containing products because of concerns over carcinogenicity in animal studies (which has not been shown in human studies to date). The “Coronavirus Aid, Relief, and Economic Security” (CARES) Act signed in March 2020 then made the changes effective by halting the sale of OTC hydroquinone products in the United States as of September 2020.
Mercury concerns
Despite these bans, hydroquinone continues to be sold in cosmetics and OTC products around the world and online. And despite being banned or limited in these products, in particular. Mercury has been used in cosmetic products as a skin lightening agent (on its own) and as a preservative.
Dr. Naissan O. Wesley
Mercury has been shown to be carcinogenic, neurotoxic, as well as cytotoxic to the renal and endocrine systems, causes reproductive toxicity, and may be bioaccumulative in wildlife and humans. There is particular concern regarding the risks of exposure in pregnant women and babies because of potential harm to the developing brain and nervous system. Initial signs and symptoms of mercury poisoning include irritability, shyness, tremors, changes in vision or hearing, memory problems, depression, numbness and tingling in the hands, feet, or around the mouth.
Organizations such as the Zero Mercury Working Group (ZMWG) – an international coalition of public interest environmental and health nongovernmental organizations from more than 55 countries, focused on eliminating the use, release, and exposure to mercury – have been working to help ensure safety and mercury levels are below the threshold deemed allowable in hydroquinone-containing products.